536: apocalypse

The legend of the horsemen of the apocalypse goes back to the first century AD. It is a gripping image, which has transcended cultures. The best-known of the horsemen is Death, riding an ashen-coloured horse. This is the only one given a name in the original. One horseman, riding a black horse, brings famine, making grain unaffordable but leaving luxuries (oil and wine) unaffected. One horseman rides a fiery red horse and brings war. The remaining horseman, on a white horse, has lost it meaning over time. Originally, it represented conquest. In the early 20th century, the white-horse man was renamed: it became Pestilence, based on the fact that in the original, the horsemen brought death by ‘sword, famine, and pestilence’.

Ever since the origin of the legend, there have been times when it seemed one or more of the four horsemen were about. There have been wars. Famine could strike at any time; it needed only one bad harvest. And epidemics, of diseases not known now, would come and go; descriptions of the symptoms sound strangely unfamiliar to us.

And there was one time when all four seemed about, riding across the entire known world. It was a bad time. It was the beginning of the Dark Ages.


It had been a bad time. Sixty years after the fall of the Roman empire, Europe had fragmented into dozens of small, warring states. Still, a vestige of Roman life survived across Europe. The new rulers were not barbarians (even if one tribe gave us the name Vandals), and they kept their regions functioning. Some trade continued and in some places (but not Britain) Roman land owners and their villas continued under the new regimes. Many Roman cities survived. But war was common and cities were falling in disrepair. Life was deteriorating.

Constantinople during the Eastern Roman empire

But there was hope of better things. The Eastern Roman empire had survived the fall of Rome. It ruled the region of Greece, Turkey, Palestine and Egypt, incorporating a substantial part of the old empire. A new, dynamic emperor, Justinian, had taken the reigns, and he was set on re-establishing the old borders. Africa and Italy were being conquered, and for the first time in a century, Rome was again Roman. The Hagia Sophia was being constructed. A new future was just around the corner.

But that future never came. A decade later, Europe lay devastated, farm land fallow and cities abandoned. Instead of a renaissance, it was the onset of darkness. And it all started in the year 536.

The first inkling of the disaster came in March of that year. Michael the Syrian, a bishop writing in the twelfth century is one of our sources. He probably quoted John of Ephesos, an ecclesiastical historian of the sixth century, and describes the event as follows (quotes in this post are taken from Antti Arjava): “In the year 848 [536/37 CE] there was a sign in the sun the like of which had never been seen and reported before in the world. If we had not found it recorded in the majority of proved and credible writings and confirmed by trustworthy people, we would not have recorded it; for it is difficult to conceive. So it is said that the sun became dark and its darkness lasted for one and a half years, that is, eighteen months. Each day it shone for about four hours, and still this light was only a feeble shadow. Everyone declared that the sun would never recover its original light. The fruits did not ripen, and the wine tasted like sour grapes.

The principal historian of the age was Procopius. He came from Caesarea in Palestine, and as legal advisor accompanied general Belisarius who fought most of Justinian’s battles. (The two fell out later. Generals and reporters can be an unstable combination.) During 536 and 537 Procopius was with the armies in Africa and Italy. He wrote: “And it came about during this year that a most dread portent took place. For the sun gave forth its light without brightness, like the moon, during this whole year, and it seemed exceedingly like the sun in eclipse, for the beams it shed were not clear nor such as it is accustomed to shed. And from the time when this thing happened men were free neither from war nor pestilence nor any other thing leading to death. And it was the time when Justinian was in the tenth year of his reign [536/37].”

Several documents mention strange weather in 536 and 537. Cassiodorus, in Italy, comments after nearly a year of haze: “So we have had a winter without storms, spring without mildness, summer without heat.” Further east, things were different. In Mesopotamia, the winter of 536/537 was a bad one: “from the large and unwonted quantity of snow the birds perished.

Another, unnamed Syriac chronicler writing probably later in the sixth century, adds earthquakes and storms: “And [Pope Agapetus] came with them to Constantinople in the month of March in the year fourteen [536]; and Severus was there and Anthemius was chief priest. And the whole city was disturbed at the arrival of Agapetus; and the earth with all that is upon it quaked; and the sun began to be darkened by day and the moon by night, while ocean was tumultuous with spray, from the 24th of March in this year till the 24th ofJune in the following year fifteen [537]. And Agapetus, when he appeared before the king, had a splendid reception from him.” No one else mentions earthquakes or storms, suggesting a fair amount of exaggeration or false facts. Not every ancient record is true!


The same Syriac chronicler gives information on the extent of the haze. The text continues: “And this we have seen from the events themselves, when many wars broke out in the west and that tyranny was dissolved, while India, and the Persian realm, and whatever dry land lies toward the rising sun, were not troubled at all. And it was not even likely that those regions would be affected by the calamity because it was in Europe that the moisture in question evaporated and gathered into clouds dimming the light of the sun so that it did not come into our sight or pierce this dense substance.”

The passage suggests that Persia and India had not been affected by the haze. There is doubt how much China was affected. There is one mention from China which may indicate a haze, saying that Canopus could not be seen. This star is very low on the southern horizon in southern China (south of 38 degrees), and can only be seen during clear weather. But apart from this indirect indication, none of the Chinese documents mention a haze or powerless Sun.

This may be related to latitude. The haze was reported from locations above 35 to 40 degrees latitude. The areas that did not have the haze (Persia, India) are below approximately 35 degrees northern latitude, and this also applies to most of China. The haze may thus have been confined to higher latitudes.


Michael the Syrian mentioned that fruit did not ripen in 536. Others also mention issues with food. Italy appears to have had a bad harvest, as Ravenna had to be supplied from the other side of the Adriatic which apparently had had a better harvest. John Lydos writing in Constantinople during the 540s, says “If the sun becomes dim because the air is dense from rising moisture – as happened in the course of the recently passed fourteenth indiction [535/36] for nearly a whole year, when Belisarios held the consular office, so that the produce was destroyed because of the bad time – it predicts heavy trouble in Europe. (The reference to moisture should be discounted, as everything suggests that this was ‘dry fog’, i.e. a high altitude haze.) It mentions that produce was ‘destroyed’ – but does not state how.

Priest carrying wheat. Temple of Horus, Edfu, Egypt.

Much of the grain in the empire came from Egypt. The lack of ripening of fruit suggests that the summer had been very cool, presumably because of the haze. However, this would not have affected the grain (and in fact cooler weather could have been beneficial). Photosynthesis may have been reduced by the haze, but we don’t know whether the dense haze had covered Egypt. However, food production in Egypt is mostly dependent on the availability of water. The Nile obtains its water from the monsoon in central Africa. This monsoon can fail after volcanic eruptions: both the Eldgja and Laki events caused low water levels in the Nile. But the reason for the ‘destruction’ of produce is conjecture. A little more scientific training of the writers could have helped a lot!

The problems in Italy became much worse. Northern and Central Italy, under Ostrogoth control, had a severe famine in 538, with one report stating that 50,000 people died. It was attributed to the fact that the land had not been cultivated during the previous year. Whether this was due to the lingering haze or to the war between the Romans and Ostrogoths is not stated.

There were also problems elsewhere. Irish documents mention a ‘failure of bread’ in 536 and again in 539. The British Annales Cambriae refers to a death toll (‘mortality’) in Britain and Ireland in 537, but frustratingly doesn’t give a cause. China appears to have been severely affected. Reports mention severe drought and dust storms, but also snow, hail and frost in southern China in the summers of 536 and 537. The Nanshi (“History of the South”) mentions what follows: “famine happened in 538, and the Imperial Court decided on the 30th of the January of the year, to implement an amnesty to the tax – cut to it’s 12 southern provinces where famines were observed, especially to those who were unable to pay the tax. (translation taken from https://history.stackexchange.com/questions/51147/what-are-some-chinese-sources-testifying-the-extreme-weather-events-of-535-536-c) The drought appears to have started in 535, which if correct means it predated the haze. A worse famine ensued in northern China. One document gives the startling number of 70% to 80% mortality among the population of one area, and states that cannibalism occurred.

When studying extreme weather, it is important to check when it began. Documents tell of a severe drought in Persia in 536 (this would have been during the summer before the snowy winter). However, this drought started long before the haze. In the Levant, a very dry period began around 522, lasting several decades and which caused water shortages from Persia to Constantinople. Thus, there was environmental stress already well before the eruption. In the Roman empire, the quarter century 526-550 had the highest number of recorded famines for the entire period 100 BC to 800 AD, but these may not be all related to the 536 haze. The long-term drought may have been an important factor. Conflicts also do not help: wars and food production are an uneasy combination.

The haze acerbated the effect of the drought, but by and large the Eastern Roman empire was well organized and could survive a few poor harvests. The worst famine happened in Ostrogoth Italy, perhaps because the people there had little access to food resources elsewhere. The British isles were somewhat affected. China may also have suffered from a lack of organized food distribution. This was the time of the Northern and Southern Dynasties in perpetual civil wars. The elite had better things to do than providing food.

What happened elsewhere in the world is not well known, due to a lack of written sources. To know more, we needed to look into other, non-written records. And the results of those investigations were much worse than what had been expected. This really was an apocalypse.

Of ice and trees

A good way to study the past is by using ice cores. These are obtained from glaciers: every year a new layer of ice forms from compacted snow, and these layers can be recognized and counted as if they were tree rings. Find a deep enough glacier, and the record can go back a long time. And the icecaps of Greenland and Antarctica are very deep indeed.

Ice core from Antarctica, with a dark layer of volcanic ash

The ice is very good at providing evidence for old volcanic eruptions. In the best case, an annual layer in an ice core contains tephra particles which signify an eruption and which allows the specific volcano and year of eruption to be identified. This is rare, because tephra tends not to travel far. More commonly, the eruption is indicated by sulphate. The amount of sulphate in the ice core depends on the size and sulphur content of the eruption, and on the distance from the glacier.

Exact timing of the eruptions has proven somewhat difficult. The annual layers can be thin and difficult to recognize. Counting errors add up, and past a millennium can easily reach 5-10 years. Luckily, it can be calibrated using a second record of the past: tree rings. These are easily counted; the science of counting rings is called dendrochronology. By combining different tree-ring records, an accurate timing has been reached going back several millennia. The width of the rings indicate how grow-some the weather was in that year. In a bad year, there may also be frost damage inside the ring, if a hard frost occured during the growing season. And occasionally, the wood contains other indicators. Twice in the past 2000 years there was a spike in the amount of beryllium in the atmosphere, possibly due to massive solar flares. The beryllium layers can be identified both in the trees and in the ice, and can be used to bring the two in line with each other.

The plot below shows the ice core and tree ring record for the period around the year 536. The top panel show the Greenland ice core, and the bottom panel the Antarctica ice core. The middle panel shows the tree rings, where green indicates the relative width of the ring and orange the change in summer temperature indicated by the tree rings. The top panel shows an impressive spike in the year 536. It was indeed an eruption. But where?

Helpfully, volcanic ejecta have difficulty crossing the equator. Northern eruptions tend not to spread to the southern hemisphere and vice versa. Tropical eruptions, on the other hand, pollute both hemisphere. Therefore, comparing Greenland and Antarctic ice cores allows one to see where an eruption happened. A sulphate spike seen only in Greenland is normally from a volcanic eruption in the northern hemisphere. One present with comparable strength in both ice cores is from a tropical eruption. The spike in 536 was present only in the Greenland ice. This means that the eruption happened somewhere in the northern hemisphere, and not in the tropics.

But on closer look, both ice cores showed a second spike in AD 540. Apparently, two volcanoes were involved, a northern one in 536, and a tropical one in 540. And that was a surprise.

The European (Irish and Scandinavian) tree rings provided further information. A sharp temperature drop was apparent in 536, followed by an incomplete recovery. A second drop occurred in 540, and now the recovery was extremely slow: only by 550 were the trees back to normal. Clearly, the second eruption had had a major impact in Europe. But this had not been apparent from any of the written documents. Something was missing.

Micheal Sigl et al (2015) rank the eruptions of the past 2500 years in terms of total amount of sulphate, converted to something called ‘global forcing’. That is a number that indicates how much of the power in sunlight is intercepted by the sulphate layer. The Sun provides us with 1000 Watt per square meter (assuming that it is directly overhead). The top-ranked eruption was in the year 426 BC, from an unknown volcano: it reduced global sunlight by 35.6 Watt per square meter. On this list, the 536 event is number 18, and the 540 eruption is number 5. If they had happened simultaneously, it would have ranked as number 3, after the 426 eruption and Samalas in 1257.

(In case anyone asks: Laki is included, and it ranks as number 8.)

The local impact on Europe may be very different from the global effect listed in the table. Regarding temperature drop in Europe (last numeric column), the 536 eruption is the top dog, and the 540 eruption ranks number 4, just after Tambora.

So Europe -and the world- was hit by a double whammy, which together made for one of the worst volcanic events of the past 2500 years – for Europe, possibly the worst one. That agrees with the tree ring record in which this decade is the coldest in the northern hemisphere over the entire period.

It leaves several questions. Which volcanoes were responsible? Why is the 536 eruption clear from the documents while the 540 eruption seems to have gone unnoticed? Were there effects elsewhere in the world? The answer to the second question turned out to be sobering: the disaster was clear to see – we just hadn’t connected it to a volcanic eruption.

Volcanic suspects

Before accusing particular volcanoes, we first need to put to rest two widely reported myths. The first of these came from a book by David Keys who claimed that a large eruption had taken place at Krakatoa in 536. There are severe problems with this claim: the Java myths which he based it on give a date which is a century off, and do not clearly refer to Krakatoa; there is also no local evidence for any such eruption. In all likelihood, this never happened. (Krakatoa is also in the wrong place for a northern hemisphere eruption)

Mike Baillie, famous for his research on tree rings, for a while moved away from a volcanic cause for the 536 event. This was because originally the timeline for the ice cores did not match up with the tree ring chronology, leaving no obvious volcanic candidate. He argued that an impact with a comet could have caused the event. There are many problems with this idea, and the mismatch was eventually solved by a better ice core chronology. (If you are interested: you need a large comet to supply enough sulphur; I estimated 5 km diameter. Something that size will punch through the atmosphere, hit the ground and leave all kinds of hints – such as, where have all the dinosaurs mammals gone, and why do we suddenly have a 100-km crater in Mexico? Stratospheric sulphate would be far from the only urgent problem.) Baillie (now retired) went back to favouring a volcanic cause. The comet has gone away (they always do) – but as with Krakatoa, the story still surfaces regularly. Myths can be long-lasting.

But let’s go back to the real world. Which volcanoes were to blame?

There is strong evidence that there were two eruptions in short succession from both the ice cores and the tree rings. The first eruption shows up only in the northern hemisphere. The reports of haze all come from further north than 35 degrees. Further south, including much of China, the skies were apparently clearer. The tree rings which show the poor weather of 537 are also from high northerly latitudes, 50-70 degrees. Finally, although the haze was problematic and caused food shortages, there are no reports of unsurmountable problems for the Roman empire with its access to Egyptian grain. It all points at an eruption at mid to high latitude, badly affecting northern regions. The haze first appeared on March 24, 536, suggesting that the eruption happened (or started) around the ides of March.


But this has not been enough to identify the culprit: we remain unclear about which volcano may be to blame. Tephra found in a Greenland ice core points at North America but not at a specific volcano. In 2018, a few tephra fragments with an Icelandic signature were found in ice cores from a glacier in the Alps, but again without a specific volcano attached. A huge explosive eruption in Iceland which could cause stratospheric sulphate for over a year would leave plenty of signs all over Iceland – nothing has been found. An effusive eruption would not put sulphates high enough to reach Constantinople (Laki did not manage this) and again, there would be a huge and obvious lava field somewhere. Iceland frequently explodes, and the Alpine tephra could easily come from other, unrelated Icelandic eruptions. Therefore, a Pacific volcano appears more likely. On the map, the eye is quickly drawn to Alaska and its arc of Aleutian islands. Is one of its islands perhaps missing? The White River Ash (Mount Churchill) has an alibi: it comes from two eruptions, one around 840 and one around 60, which are not consistent with 536. Which is a pity, because the size of the eruptions would fit the occasion: the ash even reached Europe. Was it on the other side, in Kamchatka or the Kuriles? The largest caldera-forming explosion there is dated 1650-1900 BP which almost fits: Ksudach caldera V, the second largest known caldera event in Kamchatka during the Holocene. Tephra from this explosion has been found in North America. But it is estimated at ‘only’ 20 km3 of tephra and seems a bit small and a bit too early for the 536 event. Opala, nearby, had a significant eruption around 600 AD, where the eruption column reached 20 km, but the 10 km3 of tephra seems rather small to explain the events of 536. No other smoking gun has yet been found, and neither Japan, Kamchatka or North America show other significant tephra deposits around this time. The discussion is not over, but Ksudach and Opala might be worth another look.

Perhaps we should also look at the Azores. It has frequent eruptions: about one every 20 years.(The last one was 19 years ago..) The events can reach VEI6, and the islands are well placed to affect the Mediterranean. Recently it has been suggested that some of the tephra in European peat bogs that was attributed to Jan Mayen in reality comes from the Azores. But again, the smoking gun is lacking.

The caldera lake of ilopango

The second eruption affected both hemispheres, and must have been a tropical eruption. And it was a serious eruption, which deposited 10% more sulphate in the ice than Tambora managed. Tree rings narrowed worldwide and temperatures appear to have dropped significantly, with several very cold years. There are no reports of haze. El Chichon has been suggested, but although it may have had an eruption at approximately the right time, there is no evidence for anything on the scale of Tambora. And finally, in 2010, a strong candidate was identified.

Ilopango is the largest lake of El Salvador, up to 13 by 17 km across and 70 km2 in area, surrounded by cliffs up to 500 meter high. The beauty is bewitching, but this is the dangerous beauty of Cleopatra. This beauty hosted the largest explosion in El Salvador. The lake is a water-filled silicic collapse caldera. It is located in a pull-away graben, something it has in common with Toba. Just the water volume of the lake alone (12 km3) shows that this was not a minor event, and of course the actual explosion would have been much larger. The area is surrounded by a thick white ignimbrite, up to 30 meters thick, which extends into neighbouring countries. Most of the tephra went south and south-east. The eruption had been dated to 240 AD, until Dull et al, in 2010, measured a carbon-14 date of a charcoaled tree trunk buried underneath a pyroclastic flow, and improved the date to within the period 450-545 AD. Although not quite accurate enough for a secure identification, it makes Ilopango the most likely source for the 540 eruption. Dull et al claimed it as the source of the 536 eruption, but it is too far south for that.

The volume of the eruption is estimated at 84 km3 of tephra, or a high VEI6. At 15 degrees north, it fits the requirement for a tropical eruption and an eruption this size would have affected both hemispheres. Central American volcanoes have typically a high sulphur content of 1000 ppm or more. This means Ilopango can have had 40% more sulphate than Tambora, even though it was a smaller eruption.

Ilopango is a repeat offender. The oldest dated eruption occurred 1.7 million years ago. Since that time it has exploded regularly, including three events in the past 57,000 years. The largest event produced over 100 km3 of tephra. It should now be safe for quite some time (there was a minor eruption in 1880) but one may wonder about the wisdom to build the capital, San Salvador, only 10 kilometers from the caldera.

The identification of the 540 eruption with Ilopango is still being discussed. Timing, location, size, and lack of any other convincing competitor, all make it a plausible candidate. But it is still possible that another volcano pops up to explain the events of 540.

Impact of the 540 eruption

Isopach for the Ilopango tephra

Area of demographic collapse following the TBJ eruption (red line) Source: Dull et al. 2010

One may expect the largest effects from the Ilopango explosion to have been in Central America. There may have been no survivors within 50 km from the bang, based on the depth of the tephra. El Salvador was the southern limit of the Maya empire. All Maya settlements in El Salvador were destroyed. The Maya were a very long-lasting civilization who obviously knew how to survive and prosper in the rain forest environment. Over 2000 years of history, their empire showed several collapses and set-backs, including a century-long interruption from around 550, when building work ceased and some cities were abandoned. Tikal, the main Maya city of the time, was defeated and suffered significant damage. Surprisingly, Copán, much closer to the eruption, came out as victor: one may speculate that its army was bolstered by the refugees from El Salvador. The period is called the Maya Hiatus, and its start is shortly after the 540 eruption. The Maya civilization overall was less affected, and eventually there was a full recovery, although in El Salvador it took decades to centuries before a few sites became re-occupied. The Mayan had bigger set-backs at other times, which are thought to be drought-related. But the Hiatus may have been triggered by environmental stress caused by Ilopango.

Teotihuacán, near modern Mexico city, was the largest city in Central America, with a population in excess of 100,000. It was one of the wonders of the ancient world. If you ever have the chance, do visit – but be careful with what you buy from the street vendors. The city was burned and abandoned around 550, apparently by its own people as there is no sign of any invasion. This is a far more significant event than the Maya Hiatus: Teotihuacán, the most powerful city in all of the Americas, was abandoned and forgotten. There is a strong case for major upheaval in the area and the 540 eruption is a major suspect. Both Tikal and Teotihuacán are well outside the tephra area. SO2 will have spread beyond the tephra, and this can kill vegetation. In this way, Laki killed the barley in western Europe. But the fact that Copán survived relatively unscathed suggests that the case is more complicated. The cold (dry?) climate of the decade may therefore have played a role in the upheaval, rather than the proximity to the eruption.

Further afield, we have Chinese reports of events in this period. “the extraordinarily strange climate continued, finally the Emperor declared on November 541: Applying the Road Of Heaven in order to share the benefit of the earth’ is the old proverb by sages. Except for the lands for the Imperial Household, let us give all the abandoned lands and mulberry fields and houses to the poor. We will look into the labor power of these poor, and in accordance with it, let’s give them the appropriate size of arable lands.” The famines in southern China worsened throughout the 540’s.

Let’s return to Europe. There is no indication that the weather in the Eastern Roman empire was particularly bad during 540, and no haze was reported apart from an unclear mention of ‘poisonous air’ related to the coming epidemic. If there was haze, it is likely to have been much less strong over the Mediterranean than it was in 536. But the lack of reports may in part be due to other reasons: few personal records were written during the catastrophe that enfolded in the 540’s, and those discussed more urgent events. The medieval historian Roger Wendover describes that in 540/541 there was “a comet seen in Gaul so vast that the whole sky seemed to be on fire”. That can’t have been a comet (which would have been in many manuscripts of the time), but perhaps is the 540 eruption. But the veracity of the claim is rather unclear.

Tree rings at high time resolution. Source: Mike Baillie, 2015.

If instead we trust in tree rings, the impact of the 540 eruption is very clear. The tree rings show that there was a pronounced dip in temperature in 536 when the climate cooled by as much as 3 degrees. This number is from Scandinavian and Siberian trees, at high northern latitudes. Further south the temperature drop may have been less. The temperature mostly recovered over the next three years, but in 540/541 there was another drop, again to 2-3 degrees below normal. This dip lasted 10 years. Note that the recovery in 542 may have been real but it may also be due to inherent year-on-year fluctuations in the data.

The narrow tree rings were replicated world-wide, in data from Europe, North America and Argentina. In some places only the 540 dip was seen and not the 536 one. The 540 event was world-wide – the 536 event was not.

Why did the temperature continue to decline for years after the 540 eruption? Stratospheric sulphate lasts at most 3 years before it has all returned the earth, and during this time the depth of the haze steadily reduces. Tambora caused one particularly cold year. We can speculate that the double eruption caused the cold period to last long enough to cool the Atlantic ocean, which could have prolonged the cold spell. Separately, the eruptions were large but not exceptionally so. Together they caused the coldest decade in the northern hemisphere over 2000 years, with a cooling that was 50% larger than that of the double eruption of 1809 and 1815 (Tambora). Globally, the decade was ‘only’ the third coldest. The northern hemisphere was hit hardest.


The 536 sulphate haze was obvious for a full year. Models show that for the sulphate to remain aloft such a long time, the explosion must have reached a height of about 25 km. The plot (from Toohey et al. 2016) shows the predicted reduction in strength of sunlight at the latitude of Constantinople. The 30hPa line corresponds to about 25 km altitude; the other two are lower. The amount of sulphate that was used is consistent with the ice core data. Shortly after the eruption, sun light was down by 65%, and even by the end of the year it was still down by 33%. Above 60 degrees latitude the reduction was even a bit worse. The models suggest that the impact of 540 eruption would have been similar, making the lack of written records surprising but explaining the strong tree-ring signal.

The effect on summer and winter temperatures is shown in the next plot, taken from the same paper. The colours show the average effect over the decade. The very large anomaly over part of the Arctic ocean is because of the expansion of sea ice, which in the simulations almost reaches Iceland. It is possible that in later years, the melting of this newly formed ice cooled the Atlantic ocean, and caused cooling up to 550.

The temperature drop in Northern Europe was severe. This had consequences. Both Finland and Sweden suffered a population crash around this time with many settlements disappearing. Eastern central Sweden was largely abandoned, and according to one estimate, the population of Scandinavia halved. The cold weather is a likely cause. In high-latitude climates, farmers are normally resilient against a severe winter. (The main issue may be access to water.) Cities can be a bit more affected, especially if snow and ice prevent supplies from reaching them. Later in the Middle Ages, things became worse, and cities could quickly run out of food in bad winters. A critical point was bread: this required the water mills to run, in order to grind the grain. If the rivers were frozen, the mills stopped – and soon there was no more bread. But farming communities tended to store sufficient food to last the winter and spring.

A cold summer was a much bigger problem. That meant that less food could be grown, and winter supplies might run out. Such a summer may have put an end to the Viking settlements on Greenland. Several cold summers in a row could be disastrous. Was this what happened? On the island of Gotland, off the Swedish coast, the settlements were burned by invaders. Were these invaders starving farmers from the main land? They didn’t settle: the island became temporarily abandoned.

There may have been population crashes also in Germany and the Netherlands, but very little is known about this. Was it related to the climate famine? Perhaps – but there were other horsemen about.

The Justinian plague

Justinian was among the greatest emperors of the Roman empire. He took power in 527 AD. At the time, the Western Roman empire was long lost, and the Eastern empire was fighting a war of attrition with the Persian empire. Justinian managed to buy off the Persian empire, albeit at considerable cost: 11000 gold pounds each year. That freed up the army, and he began to expand into the Mediterranean. Carthage in North Africa fell in 534, in a battle that ended the Vandals as a major power. The re-invigorated Roman armies invaded Italy in 535 AD and quickly took Naples and Rome from the Ostrogoths. The Ostrogoth armies came back and besieged Rome for a full year, but the Romans managed to hold the city and in 538 the Goths retreated. By 540, much of the Italian peninsula was back under Roman control. The empire was well and truly being re-established, with its new capital in Constantinople.

Justinian I

It is interesting to guess what might have happened. On the one hand, the warring parties were evenly matched and Justinian would have had to commit many more troops to gain a lasting conquest, as he had done in North Africa. The invasion seemed half-hearted. On the other hand, if successful and perhaps in alliance with the Goths, a large Mediterranean power could have given stability and a critical mass for technological progress. Civilization could have skipped many hundreds of years, directly into the world of the late Middle Ages. It was not to be.

The apocalypse started in 541 when a new disease appeared in Egypt. One report states that it had originated in Ethiopia, but this must be considered doubtful: it was common to blame Ethiopia for mishaps. Procopius tells the story:

“It began with the Egyptians who live in Pelusium. It divided and part went to Alexandria and the rest of Egypt, and part to the people of Palestine, the neighbours of the Egyptians, and from there overran the whole earth. This disease always began from the coast and then moved up to the country inland. The plague lasted in Byzantium [Constantinople] for four months and was at its peak for about three. At the beginning not many more people died than usual, then the disaster grew greater, and finally the number of dead reached five thousand a day, and then attained ten thousand and even more than this.

The numbers may be overstated, but the death toll is believed to have exceeded 250,000, out of a population of 500,000. The effect was devastating:

At that time it was not easy to see anyone in Byzantium out of doors; all those who were in health sat at home either tending to the sick or mourning the dead. If one did manage to see a man actually going out, he would be burying one of the dead. All work slackened; craftsmen abandoned all their crafts and every task which any man had in hand.

The disease moved on, but became endemic in the Mediterranean and eventually returned to the city in 558 AD. Agathius wrote:

During that year at the beginning of spring a second outbreak of plague swept the capital, destroying a vast number of people. From the fifteenth year of the reign of the Emperor Justinian when the plague first spread to our part of the world it had never really stopped, but had simply moved from one place to another, giving in this way something of a respite to those who had survived its ravages. It now returned to Constantinople almost as though it [had] been cheated on the first occasion into a needlessly hasty departure. People died in great numbers as though seized by a violent and sudden attack of apoplexy. Those who stood up to the disease longest barely lasted five days. People of all ages were struck down indiscriminately, but the heaviest toll was among the young and vigorous and especially among the men.

The disease started with a fever, and within a day progressed to the classical plague symptoms. It became so bad that people reportedly started wearing name tags when going out, so that if they died suddenly they would not be buried anonymously. Constantinople may have lost 40% to 60% of its inhabitants. The empire overall is said to have lost 10 million people. The total population of the empire was around 25 million; it implies a mortality rate similar to the Black Death. Farming was badly affected, with many farms empty and abandoned. Famines followed in 542, 545, and 546.

The plague had significant impacts. New wars broke out with Persia, and the man power to fight three fronts (including North Africa) was no longer available. Much of Italy had to be given up, until the Persians (whose armies were also being decimated) could be bought off again. After 550, new armies were send and Italy was conquered again, against an equally depleted Ostrogoth army. A successful incursion was made into Spain. Now the Eastern Roman empire reached its greatest extent. But the armies were much smaller, and largely consisted of mercenaries. Agathius wrote “whereas there should have been a total effective fighting force of six hundred and forty-five thousand men, the number had dropped during this period to barely one hundred and fifty thousand.” There were not enough people left to keep control of such a large empire. The economy had also become impoverished. Gold coins after 540 contained much less gold than those minted before. In 568, Italy was invaded by the Lombards and Roman control of the area crumbled.

If the plague hadn’t come, it seems possible that the Roman empire would again have controlled the entire Mediterranean, and possibly Central Europe as well. That was no longer possible. Instead the empire began its slow contraction to its eventual demise, nearly a millennium later.

What was this disease? The symptoms were those of bubonic plague, Yersinia Pestis. This identification has been challenged, mainly because there were some symptoms which were not present in the later plague epidemics, and because it started in Africa rather than Asia. However, DNA fragments found in graves point at bubonic plague. The plague originally came from China and it may first have spread with the westward migration of the Huns, establishing itself in the area. A different strain of this bacterium would later cause the Black Death, and a third variety caused the 1894 Asian epidemic.

Over the next 200 years there were a number of outbreaks, until the disease finally disappeared around the year 750. The overall death toll over those 200 years is estimated as between 50 and 100 million. This was at a time when the world population was perhaps 300 million.

What caused the sudden spread? The plague is carried by the fleas on rats, but can possibly also be transmitted through human fleas, person to person. The bacterium makes the fleas ravenous; flea bites now infect the next victim. The plague quickly became a disease of the poor. Both in 540 and in 1347, the plague followed a major volcanic eruption. In 1347, the disease spread from the Crimea, where poor, wet and cold weather was the trigger, perhaps causing rats to invade the food stores which were shipped around. In 540, the food came from Egypt with a very different climate. One paper proposes that the exceptionally cool summer benefited the Egyptian rats, and allowed their numbers to explode. Something allowed plague-carrying rats to get into the grain storage. The fact that the disease always started at the coast shows that ships carried the rats, probably as part of the grain transport. In times of shortage, there may have been pressure to ship as much food at as fast a pace as possible. Fast food can be a killer.

It has been suggested that a deficiency of vitamin D, caused by the lack of sun, made the population vulnerable to the plague. This does not fit well with the dates, as the sunless year was several years before the epidemic. If 540 too was a year of haze, this was not recorded.

The plague spread beyond the Eastern Roman empire. Much less is known about this, because of the lack of local written records after the retreat of the first Roman empire. Archaeology has found that skeletons in an early medieval cemetery in Aschheim, Bavaria contained DNA from Y. Pestinus. The disease had either managed to cross the Alps or spread independently to here. The DNA also showed that although it was first recorded in Africa, the 541 plague, like the 1345 and 1894 epidemics, had its origins in Asia. Similar evidence was found in France, where Gregory of Tours reported that plague was raging by 543, noting “soon no coffins or biers were left. 6 or more were buried in one grave.

Much less is known about the spread of the plague elsewhere in Europe. The best documentation exists for Ireland, albeit written down some 50 years after the events. The 6th century Irish invented their own word for the disease: blefed. The Annals of Tigernach mention ‘a great mortality, which is called blefed’ and which according the the Annals of Ulster arrived in 545. Nearby, Maelgwn, king of Gwynedd in Wales, was said to have died of the “Yellow Plague of Rhos” around 547. The lack of written records in Britain makes it hard to know whether the plague reached here. (There is a written history by Gildas, dated to 540, but his story is in poor agreement with what we know from other sources.) However, there is indirect evidence that there were significant changes, at the end of so-called ‘sub-Roman Britain’ (the period after the Romans had left but before the anglo-saxon became the dominant power). Whether this was due to famine or plague is not known. By 540 AD, romanized Britains remained in power in the centre, west and north, and Saxons held power in the southeast, up to York and Bournemouth. This stable situation collapsed in the next few years, and by 550 the AngloSaxon expansion resumed. The important Roman town of Calleva Atrebatum (in Hampshire) disappeared around or shortly after 550.

The de-peopling of Scandinavia may have been due to either famine or plague. The former is perhaps more likely. Plague-carrying fleas need temperatures of at least 10-15 C, and this would only have been reached in summer, and possibly not at all during the decadal temperature minimum.

A word of caution is needed here. It is always hard to proof exactly what happened when and why. For much of the world, we lack written documents. Archaeology rarely gives dates accurate to a decade. In Britain, we know that the cities changed and declined after the Romans left, but we don’t know exactly when they were finally abandoned. The Anglo-saxons knew the Roman cities – they build new settlements a few kilometers away. The suggestions that the events after 536 fatally weakened the remaining cities is plausible but can not be proven. In America, it is not possible to proof a link between events such as the fall of Teotihuacán and the eruptions even though it seems likely. More research is needed – especially a more precise date for Ilopango would be useful. The strongest case for catastrophe outside of the Roman Empire comes for the tree ring record. This really was a period with exceptionally cold weather. No country survives well with a lack of food. And where we have a good written record, we know that this decade was apocalyptic (Roman empire) or highly damaging (China). The fact that the timing approximately coincides with significant changes elsewhere makes it plausible that other places were also badly affected. Understanding the past is like Plato’s prisoners in the cave, who can only see shadows on the wall and from that have to infer what is happening outside. But here, the shadows seem terrifying.

The four horsemen

Ten years after the Roman empire reached its greatest promise, its future had been lost. And the catastrophe went further, encompassing China, Mexico and Scandinavia. Perhaps 10% of the world population died. The apocalypse came swiftly, unexpectedly, and without anyone knowing where it came from. Either of the two eruptions would have been survivable. The combination of the two left the world vulnerable. The four horsemen saw their chance and rode out: famine, war, plague and death attacked and destroyed the weakened civilizations.

This is how the Dark Ages began. One disaster was manageable. Two simultaneous disasters became a catastrophe. And the third disaster truly brought apocalypse.

Albert Zijlstra, March 2019

part of Four Horsemen. Albrecht Duerer, 1498

Many articles can be found on these events, although few tell the full story. Scientific papers can be harder to locate. Here are some of the papers I used for writing this post.

  • Michael Sigl et al., Nature, 543–549 (2015): Timing and climate forcing of volcanic eruptions for the past 2,500 years.
  • Joshua North,  Armstrong Undergraduate Journal of History, 3, no. 1 (Jan. 2013): The Death Toll of Justinian’s Plague and Its Effect on the Byzantine Empire https://www.armstrong.edu/history-journal/history-journal-the-death-toll-of-justinians-plague-and-its-effects-on-the
  • Antti Arjava: Dumbarton Oaks Papers, Vol. 59 (2005), pp. 73-94: The Mystery Cloud of 536 CE in the Mediterranean Sources
  • Bo Gräslund and Neil Price, 2012, Antiquity, 86, p 428-443: Twilight of the gods? The ‘dust veil event’ of AD 536 in critical perspective
  • Matthew Tooney et al, Climatic Change (2016) 136:401–412: Climatic and societal impacts of a volcanic double event at the dawn of the Middle Ages
  • Mischa Meier, Early Medieval Europe 2016 24 (3) 267–292: The ‘Justinianic Plague’: the economic consequences of the pandemic in the eastern Roman empire and its cultural and religious effects
  • And some Volcanocafe posts related to this topic

  • When eruptions make a difference
  • The Maya collapse: a history in three volcanoes
  • The Mayas and their lack of volcanoes
  • The 1342 St Mary Magdalene flood
  • 274 thoughts on “536: apocalypse

      • Don’t worry Rock, the apocalypse is big enough for everyone… 🙂

    1. Just one small point, when it says year -426 that is in astronomical years which has a year zero (1 BCE), so it is 425 BCE

    2. “How can you lose a volcano ??” If big enough, it digs its own grave then jumps in…

      From where it isn’t, I’d suspect the Aleutian area, as those volcanic islands grow and shrink, even come and go, and the weather is harsh enough to remove evidence.

      Hopefully, some fortunate geologist will happen upon 536’s spoor…

      • Problem I see is that when a volcano digs its own grave in this way it leaves great steaming piles of its innards all over the countryside; Not something easily overlooked. And the areas with most of the usual suspects -Alaska, Kamchatka, Kuriles, Japan- are all served by highly professional volcanologists who would certainly have noticed. So either they’ve got an eruption date badly wrong (even if it’s impossible to get an absolute date from C14 dating, it’s usually possible to get a relative date from the stratigraphy of the deposit). Or the 536 culprit is elsewhere. How far south are we looking? Are the Philippines too far south? Tropical forest can conceal a good deal -look at Pinatubo for example.

        Or maybe Volcano X wasn’t ‘subaerial’ at all. Maybe pre-paroxysm a small volcanic island or a shallow-depth submarine centre where most of the evidence would land on the sea floor. As with say Krakatau in 1883, or Tavui near Rabaul

        • The answer to how a volcano can disappear is actually incredibly simple.
          The white sands ash sneakily hid for a very long time.

          • Do you mean White River Asn? Thing with that was, the geologists knew it was there, it wasn’t that inconspicuous….but it took quite a while to work out the source (and at that it took two attempts before they got the right culprit). And Mt Churchill has most certrainly not disappeared. It’s really the mirror image of the problem I mentioned – where the sulfate spike and climate effects indicate a paroxysm, but the physical evidence is missing

            • I mean’t the white river ash, I just garbled the words.
              Yes, they knew about the eruption for a long time, and guessed wildly wrong for a long time for exactly the reason everyone missed my candidate.

          • Have the Canary Islands been discounted as the source of a major eruption? There is possibly evidence of a large eruption having occurred previously, where much of El Hierro is missing, due to a flank collapse.

        • Volcanologists just discovered the Samalas eruption in the last 10 years, which was the largest of the last 2000 years, and very close to Tambora. So I wouldn’t be so quick to assume we’ve found all the eruption candidates and tephras.

          Also worth mentioning, depending where a volcano erupts, the tephra can be easily lost. If the tephra lands on top of a glacier, it’s easy for it to get washed away over the years or buried beneath the glacier itself. Conversely, tephra that simply lands in the ocean is extremely tough to come across and map effectively. This could be particularly relevant in the “island gone” possibility raised by Albert (especially relevant for the Aleutians).

          I also wouldn’t discount the Ryukyu islands north of Japan and south of Kamchatka as well. Could have easily come from there.

          • The Ryukyu Islands? I’m not so sure about that, because there likely would have been at least some historically recorded accounts by the Japanese/Okinawans. But then again…

            BTW, the Ryukyu Islands are SW of the main four islands of Japan – Nansei-shotō is the name more or less commonly used by the Japanese – and it literally means “Southwest Islands”.

            I think what you meant are the Kuriles between Hokkaido and Kamchatka.

            The deamon still likes you in the dungeons! Hereby released. -Admin

        • Given where the haze was seen, we are looking for a volcano north of 40 degrees. Japan is possible. The Philippines are too tropical.

          • Vesuvius erupted in 536. GVP does not give it a VEI but it is around 40N.

            • Not even remotely close to be big enough, not even it’s big eruption was big enough.
              To do a car analogy, we are looking for a main battle tank and Vesuvius is a Fiat 500. Vesuvius is not a big volcano, it just chose to drive into a crowded market place.

              Whichever volcano it was, we are looking for one of the big hitters in the northern hemisphere.

            • Canaries may be a little too far south but it may still be an option. It should be on the list.

            • The main problem with the Canaries would be that they are very well studied and the largest Holocene explosive event was a VEI 4 eruption on the flank of El Teide (Montaña Blanca dome complex) around 2000 yrs BP.

    3. Fascinating! Sort of like a detective story that leaves you hanging. I can imagine that someday the mystery will have a better suspect. Who is doing the most work in this area? How are they funded?

    4. Fantastic article Albert.

      I have two small points though, trade was in the Nordic countries more abundant in wintertime than in summertime. The reason for that is that it is easier to travel and haul loads over snow, than on the non-existent roads at the time.
      This practice lingered on with winter weddings (easier for guests to travel), over to the entire logging industry that only operated during the winter. Same with mining. My paternal grandparents used to work with logging and mining during the winters, and at their farmstead during the summer. And there are written sources about spanning back for as long as we have had written languages, including some examples in futhark.

      The other thing is that I have a spiffing candidate (I believe at least, problem is that I have not gone from the religious state of my belief to upgrading it into science). I do have a lost volcano with a very large eruption, problem is the specific dating needed. I am though working on it.
      Ie, I have a large disappeared volcano that had a large eruption somewhere around the timeframe, but timeframes does not proof make. I have though jumped up and down on the volcano in question.

      • I am very curious. Is it for tropical or for the northern eruption? For the northern one, I did wonder how secure the dates for Ksudach and Churchill were. Especially Churchill would make a strong candidate. The date of around 840 for its eruption did seem a bit funny because there is no strong signal in the ice core at that time. And it was a large eruption.

        Interesting bit of information on Swedish winter travel! Communities at that time would have been largely self sufficient but cities always have a harder time. Further south in Europe, there are many records of famines in cities (often in France) when snow and ice brought movement to a halt. Swedes are obviously more winter-proof.

        • We are hellishly winter-proof. Your point is though highly accurate that we are not as summer-proof. Even a partially bad summer caused famine. Before the second world war there was one roughly every decade as the harvests failed during colder than average winters. The developed of world trade and free trade agreements put a stopper to the famines.
          My paternal grandmother was acutely aware of them, and took the time to teach me how to make bark-bread, and where to harvest the best bark for it. I will never forget that lesson, and others.

          • Bark bread? I don’t think I’ve heard of that. I wonder how that tastes? Can’t imagine that it’d taste anywhere near as good as real bread! Just like substitutes for coffee during WWII and the East German coffee crisis in the 1970s.

            Good article, BTW!

            • Sorry – just realized that the article was written by Albert, not you. :sheepish:

            • If you enjoy the really heavy rye breads with more fiber than a wool farm, then you would probably like bark bread. You use the inner bark of spruce taken on the northern side (thinnest outer layer). Just dry it and grind it and then use half/half with regular flour.
              The bread becomes grayish and containes a lot of nutrients and fiber. Healthier than 99 percent of all store bought bread.

              You can do it as a sour dough, or use yeast (long rise time). If you are in a hurry you can supplement the yeast with baking soda.

    5. What an impressive piece of scholarly writing. You’ve drawn together a lot of stuff. Many thanks for this!

    6. The problem with my proto-candidate is also that it is to small to create the effects described.

      This got me thinking. We have two time-frameal candidates, Ksudach and my candidate. Both had large eruptions, but too small to have the desired effect.

      My mind is simplistic, and I got to thinking along a way that most people discard since they believe that it is improbable. And that is that it could have been a double-tap.

      Double-taps are more common than believed. Take Iceland for instance, every seventh eruption in Iceland is a double-tap. Or in more common vernacular, two eruptions at the same time.

      And there is an even bigger precedent double-tap event than the 536. I am obviously talking about the 1628BC double-tap of Thira and Aniakchak, with Thira being the famous eruption and Aniakchak not even being known about, and still Aniakchak stod for 70 percent of all the gunk injected into the atmosphere that year.

      The effect of two large eruptions on either side of the world was pretty majestic. And two VEI-6es on either side of the world would probably fit the smaller bill of 536.

      Obviously I do not have even a shred of evidence for what I just wrote about 536, but it would explain things.

      • i know Aniakchak and it’s scary impressive…. looks like it belongs to another world in the winter pictures…. pics at Alaska Vol Observatory AVO.

      • To me, the ice core data suggests the possibility that 1783 was also a double-tap event. Assuming the dates for the ice cores are fairly accurate, the initial sulfur spike was early in 1783. Laki did not erupt until June.

        • I haven’t looked at the detailed record. But two comments: the sulphate does not come with a monthly date. Instead, you can try to see how early it is in the annual layer, but this also depends on how much snow falls later in the year. The accuracy is not absolute.

          On the other hand, there were other eruptions. There was an of-shore eruption in Iceland in February, and a volcano in Japan erupted in the spring.

          • From the detailed data, in addition to the Laki date issue, the 1258 sulfur and cimate impact attributed to Samalas seems out of whack.

            Samalas was tropical and about the same size as Tambora. I’d expect a similar bi-polar signature. The 1233 bipolar spike seems more in line and about the right size to me.

            If so, maybe 1258-1259 was from separate very large NH and SH eruptions.

            • I recall that tephra from Samalas was found in the 1258 ice. That would make a secure connection. Note that time of the year can play a role in how much sulphate reaches either pole. It depends on snowfall.

            • Well, Indonesian volcanoes by reputation, are quite gassy.

              “The estimated height of Mount Samalas before its 1257 eruption was 4,200 metres (13,800 ft). According to a 2013 study, the eruption destroyed the mountain by ejecting up to 10 cubic miles (42 km³) of rock into the atmosphere. “


              As for asymmetric injection of the SO2 load… a little bit of push will go a long way. This is the current 250mb wind stream for the area. Most of the flow in that region is towards the northern hemisphere.

            • 1230 Was also a massive bipolar thump and no slouch at #7 on the list.

              My push back on a tropical Samalas (or other tropical explosion) as the primary source of the 1257-1259 sulfur is the inconsistency in the NH and SH ice records.

              The SH spike spanned a nearly 5 year section of the data.

              The NH spike was more like 2 years.

              1. I would not expect such a wide variation in the timing of the distribution of the sulfur from a single tropical source.
              2. As you pointed out in your later post, the sulfur form a single blast could not stay airborne for that long.
              3. Both the NH and SH spikes are much larger than what Tambora deposited from a similar size and location in the world.

              My question to round out this thought is could 1230 have been Samalas and the 1257-1260 spike have been the result of separate NH and SH eruptions?

            • Lavigne et al who made the identification write:

              ‘glass geochemistry of the associated pumice deposits matches that of shards found in both Arctic and Antarctic ice cores’

              which should be conclusive linking it to 1257 rather than 1230. In terms of SO2, the Samalas eruption was much larger than Tambora.

            • Thanks for the article.

              It is definitely a compelling case.

              I still think there are some assumptions and uncertainties around the timing and scale that are a bit less than 100% conclusive. It would also be interesting to see how the chemistry of the 1230 layers compared to the Samalas tephra and to each other.

            • OK…final final thought in this thread….

              Based on the ice core sulfur data for 1257-1261, I can easily get my head around separate large NH (perhaps Kamchatka or Alaska) and SH eruptions (perhaps Chile, Erebus or any of the Sandwich Islands)…..PLUS a large tropical blast in 1230.

              Two possibilities:

              1. If ~1257 is conclusively Samalas, then that means we are possibly missing another tropical Tambora-sized volcano in 1230 (or seprate NH & SH VEI 6’s in exactly 1230).

              2. If 1230 was Samalas, however, then we are missing 2 separate very large sulfur sources in the NH (1258-1260 spike) and in the SH (1257-1261 spike).

              I want to see the 1230 ice cores tested in more detail.

            • Really really final final comment….

              Lastly, just looking at it, the idea that it was Rinjani was more than times 2 or more of Tambora doesn’t make sense to me. The crater is not nearly as wide or deep as Tambora and even today the current Rinjani summit is nearly 1000 meters taller than the lower rim. Did Rinjani grow 1000 meters since 1258? Doubtful.

              Rinaji was clearly massive, but it still doesn’t look quite as big or as blowed up as Tambora.

    7. Just a thing here
      Albert Mauna Loa is sourely 17 km tall from her pressed down original submarine base right?
      All sources on internet says that including HVO and USGS.
      I have spent months trying to convice Carl on this stuff
      Im correct right Albert.
      The mammoth weight of the hawaiian shield edifices presses down the seafloor as they continues to grow.
      Mauna Loa is 17 100 meters tall since she started growing.
      Im absoutley soure Im correct here about these submarine giants true height.

      • The ocean floor is depressed by 8 km by the weight of Mauna Loa. That number was first published in the reference below and is generally accepted. There is a seismological boundary there. That makes the depth of the mountain 17 km. However, this is only below the peak. Underneath the flanks the ocean floor is less depressed. To get the volume of Mauna Loa, if you take the volume above the surrounding sea floor, and double it to account for the subsidence of the ocean floor underneath, you should get roughly the right number.


        • I imagine the shape of the above ground mountain inverted as a rough guess to the shape. Kilauea is 10 km thick (or at least its volcanic system is) where it is above 500 meters altitude so that might help with imagining the shape. Its going to be different in the north though kohala was almost as big as mauna loa when it was in its peak and now its pretty small so the big island is probably about 15-17 km thick and is less under kilauea right now because that part is still growing. I would expect all the islands since oahu to be probably 15-18 km thick under mountain peaks.

    8. Wonderful!! really raised my spirits (which at the moment is winter’s worst…. half way thu Feb to half way thu Mar.) Well, things could be worse…. we could have a volcano……….. (motsfo raises her head and gazes out the window… “Don’t you dare, Redoubt… don’t you dare!” ) Just wonderful reading… totally enjoyable. Best! from motsfo off to buy doughnuts.. (note the plural isn’t a typo) 😉

      • If the apocalypse cheers you up, we may need to have a word…

        • or a doughnut or 2 😉 Back now from Hubby’s post op (he did well) and have doughnuts in hand… also 3 moose bedded down in yard…. a sign of another snow storm coming in… was very careful to not disturb them coming in with the doughnuts. Still have 2 feet of old snow in yard…. but coffee in hand and doughnuts too, so things are looking up… Best!motsfo

          • We have about a foot of old snow in our yard in NE Oregon.supposed to get tall the way up to 5C today.
            -10Cnow . more snow on the way.
            doughnuts were on the menu this AM, too…

      • Jesper, I never said the figure was wrong. I just said that it was an idiotic way to count. And it would not make Hawaii the tallest volcano, that specific volcano would using that way of counting be made into 72 kilometre giant… 🙂

        • The depression would be included when calculating the accumulated lava. But for height it makes things too complex. For instance, all mountain ranges have deeply depressed crust below. So it would make Mount Everest 30 km tall (actual number made up – just something huge). Height is counted either from sea level or from base level.

          • I wholeheartedly agree, otherwise you end up with a volcano in the Andes.
            But I will return on that next week unless something explodes.

          • Andes volcanoes, even the biggest ones, are tiny piles of sand compared to mauna loa, or any of the hawaiian volcanoes actually. Maybe height is not the right word, but the earliest lava mauna loa erupted is indeed almost 20 km underneath its existing summit, and that has to count for something. I would doubt any of the volcanoes in the andes have any crustal warping that is above calling it negligible. I would also apply that to pretty much all volcanoes outside ocean basins actually, because giant 10,000+ km3 basaltic shield volcanoes basically dont exist outside oceanic basins on earth. The biggest really obvious (probably) still active central volcano on land I would find is emi koussi which is 3000 km3, and obviously this is not even close to anything in hawaii.

            • Ahem, I know that you and Jesper have a “thing” for Hawaiian volcanism. But reality is something to keep to when discussing.

              Dear flying pasta monster, now you two have gone from 17km total height from MOHO to the top of the summit, all the way to the bottom of the ejecta being 20km under its existing summit.

              Let us say that the volcano ejects 200 000 km3 a minute and is 3 cubic parsecs while we are at it.

            • 17 km is from the summit to the contact with pre-existing ocean floor, total thickness of erupted material. The MOHO is deeper, 20-21 km under the summit more or less.

            • I never said mauna loa was 20 km thick, just that it was in the general area of 15-20 km for the islands as a whole since oahu formed. But it is a known fact that the sea floor under the center of the big island has been depressed up to 8 km below the level of the ocean floor around the islands and that means the height of mauna loa and mauna kea above the ocean floor that existed when they first formed is 8+9 km under their current summits, which is 17 km. The thickness under kilauea is less, about 10 km, that at kilaueas summit is mostly mauna loa lava with kilauea until very recently being a rather minor volcano. Now kilauea is dominant of the hotspot, only rately being challenged by its neighbors, abd because of this it will grow very rapidly (as it already is, now) and become a real giant in the future maybe 150-200,000 years in the future, probably a lot bigger than mauna loa. At the upper end its future summit might tower over 6 km tall abovs the ocean. Before that is questioned yes it is definitely gravitationally unstable in the long term but if the output rate is as high as it is now that will far outpace the annual subsidence rate, if mauna loa even today in its low eruptive state, erupted at its actual summit and made a cinder cone 50 meters high that became its new summit, that would take over 2000 years to subside to the level it was at before that eruption occurred, and in that time it is plausible another eruption could happen in the same place and grow the mountain even more. This effect is an order of magnitude higher on a volcano in its true shield building phase like kilauea, which was 200 meters lower 1500 years ago than it is now.

              Quite possibly mauna kea was a lot taller in the past than it is now, and it is only in its more recent inactivity that it has subsided, same for haleakala on maui which I think is a better analogue for future kilauea than mauna loa is.

              Also carl if you are going to go that far I could say the same thing about you regarding iceland, or the volcanoes in the americas, but I’m not here to make enemies and I suspect neither are you so I’ll leave it.

            • I would also like to add that if you are accusing me of being unrealistic about hawaii, I cant recall any other place in the world erupting a conservative half a million km3 of lava in 3 million years, most flood basalts are smaller than that, even the mass extinction causing deccan and siberian traps are in the same order of magnitude as this, though similarities stop there. Silicic volcanism vs basaltic volcanism is really a non argument if you really look at the big picture, the most productive silicic volcanism might do the equivalent of a VEI 8 every 50000 years, the last VEI 8 in the andes was a million years ago, and the big island of hawaii didnt exist then or was a tiny island south of what was then an even bigger maui nui. Toba was the last definite VEI 8 75000 years ago, kilauea was still below sea level then, having its surtsey moment, and now it is one of the biggest volcanoes on earth. Even going much more recently, in the past 1500 years, kilauea alone has probably been supplied with about 300 km3 of lava and erupted close to 90% of it, (which is roughly the DRE equivalent of 800 km3 of tephra with the density of water), there hasnt been a silicic eruption even close to that size until you go to the oruanui eruption from taupo 23000 years ago.

              It might not be as impressive as a VEI 8 but the true reality is that hawaii has no competitor if you are going to look at sheer scale of volcanism as a whole, kilauea on its own is responsible for 1/100th of all the magmatic activity on earth today, that doesnt sound like much but that is 1/100th of the estimated magma budget of the entire earth every year (roughly 20 km3), and that number both includes divergent plate boundaries and the at least 1500 other known active subaerial volcanoes. I’m not even exaggerating when I say the only real step up from what hawaii is doing now is a tamu massif #2.

            • I agree that Hawai’i is one of the most impressive volcanic regions in the world. Comparison to Iceland is not trivial since they are so different. You would want to compare to Iceland and Hawai’i as a whole, not volcano-by-volcano. Lava production is higher on Hawai’i (mighty have bene different at the start of the holocene), number of eruptions is higher (I think) on Iceland. I don’t think the case for Hawai’i becoming more active is convincing. Activity goes up and down over the ages and it probably depends a lot on how well aligned the plume is with openings it has melted in the crust. Kilauea is the more active at the moment, but I would hesitate to extrapolate the past 1500 years to the next 150,000 years.

              It is people’s right to push the case for their favourite volcano, whether it is Iceland, Hawai’i or Victoria. And it is other people’s right to look critically at these cases. That is VC.

            • Hawaii has definitely increased in activity since oahu formed, kauai is pretty big but is a singular volcano with more radial eruptions, oahu was 2 big volcanoes, and maui nui and big island are clusters of multiple even bigger volcanoes. If you draw an outline of the submarine bases of oahu to the big island it is a single massive plateau of lava about 10 times the area of the big island (maybe not that much im going by memory).

              It would also make a lot more sense for the activity of 1500 years ago to be the final gasp of mauna loas shield building stage, it was largely the size it is now even 10,000 years ago, and between 9000 and 2000 years ago it was largely inactive like it us now, and kilauea probably grew then, and now it is growing again but even more. 1/30th if kilaueas volume is in the last 1500 years, while the other 10700 km3 has to be spread over the previous 200,000 years, which gives a much lower supply rate than today which also lines up better with mauna loa being the dominant volcano in the pleistocene. Maybe mauna loa might take the hotspot every now and then in the future but I highly doubt it is going to take it off kilauea to any meaningful degree anymore.

              I would suspect the gradient of the bottom of the crust under the island is causing magma to pool under kilauea much more than elsewhere and this is also supported by CO2 emissions from deep magma being higher than expected at kilauea and lower than expected at mauna loa.

            • The Iceland to Hawaii comparisons and impact also have to take into account that most of the time Iceland’s activity is sub-glacial. Iceland would likely be much taller and have been much more impactful if it’s activity was consistently sub-aerial.

    9. Every month, Albert, you surpass yourself. That article was so readable and so informative, yet like the best serial drama, leaves the watcher/reader hungry for more.

      • I agree. Thank you Albert, for a very detailed and interesting analysis of the evidence

    10. i wonder if Carl could do an article on bark bread…… ??? sounds very interesting.

      • I could, but it would be wildly out of topic.
        But I can say that I learned far more about surviving out in the forest in the middle of the winter by my grandmother, than I ever did in the army survival training weeks.

        • “it would be wildly out of topic”

          Not so! A couple of lady Geologists some time ago did a web article somewhere about the similarities of bubbles in rising bread with bubble nucleation in magma.

          As for wilderness training, I think your grandmother may have had a lot more experience to draw from than your instructors. Her data sources probably far exceed that of the trainers. Folklore and tales handed across families are a powerful information base.

          My parents grew up during the Great Depression, one side effect is that I tend to keep everything that might be handy in the future. This makes me into a bit of a pack-rat… and why I have a couple of fairly strange architecture machines holed away in my home shop.

          DIGITAL ceased to be an independent company in 1998, yet I still have an Alpha PC (21164) CPU based machine under my bench.

          • And you can still put the latest version of VMS on it!


            VSI OpenVMS on Alpha V8.4-2L1

            VSI OpenVMS Alpha Version 8.4-2L1 is the first release of the OpenVMS Alpha computing environment by VMS Software, Inc (VSI). It is functionally equivalent to VSI OpenVMS on Integrity V8.4-2L1. The purpose of this release is to provide users of the aging DEC Alpha hardware platform with a VSI-supported upgrade path to the latest versions of OpenVMS, in preparation for migrating to modern Intel x86-64 hardware.

            Yes that does mean VMS is being ported to X64…


            BOOTMGR> B

            %VMS_BOOTMGR-I-TRANSFER: Starting VSI OpenVMS…

            %%%%%%% VSI OpenVMS ™ x86-64 XDELTA Console %%%%%%%

            XDELTA on COM1 port
            Taking 1st SYSBOOT breakpoint
            VSI VMS X86 XDELTA Debugger [SYSBOOT], XEWF, Dec 13 2018 13:37:32

    11. As for the plague of Justinian, and others, I tend to favour Ebola as the candidate – “These differences have fuelled many alternative theories for the Black Death, which push Y.pestis out of the picture. Was it caused by an Ebola-like virus? An outbreak of anthrax? Some as-yet-unidentified infection that has since gone extinct? In 2000, Didier Raoult tried to solve the debate by sequencing DNA from the teeth of three Black Death victims, exhumed from a French grave. He found Y.pestis DNA. “We believe that we can end the controversy,” he wrote. “Medieval Black Death was plague.”

      Raoult was half-wrong. The controversy did not end. Some people argued that it’s not clear if the remains came from Black Death victims at all. Meanwhile, Alan Cooper analysed teeth from 66 skeletons taken from so-called “plague pits”, including the one in East Smithfield. He found no trace of Y.pestisHe found no trace of Y.pestis. Other teams did their own analyses, and things went back and forth with a panto-like tempo. Oh yes, Y.pestis was thereOh yes, Y.pestis was thereOh yes, Y.pestis was there. Oh no it wasn’t. Oh yes it wasOh yes it was.

      In 2010, Stephanie Haensch served up some of the strongest evidence that Y.pestis caused the Black Death, using DNA extracted from a variety of European burial sites. Schuenemann and Bos bolstered her conclusion by taking DNA from bodies that had been previously exhumed from East Smithfield, and stored in the Museum of London. “We sifted through every single intact skeleton and every intact tooth in the collection,” says Bos. They extracted DNA from 99 bones and teeth and found Y.pestis in 20 of them.”


      I watched a television documentary that matched written descriptions of the progress of symptoms, of the Black Death, evidence for the absence of rats in the UK, completely, and the proof of its 2 weeks incubation, which meant that everyone dying at the same time was a full fortnight after they had infected each other, so the disease was already 100 miles ahead by the time symptoms appeared. Ebola killed 70% of those infected in the 1860s. Evidence that was in the libraries of Zanzibar has been lost, but was used by MM Kaye in her novel, Trade Winds

      • I also still favour the impact theory which Mike Baillie has now discounted. A large impact would burn, send up water, trigger earthquakes and volcanoes, and make for an air burst which would be bright as day when it impacted the upper atmosphere. The recent Chelyabinsk impact is one example. There were reports in 2011 of the same image passing over Brazil in April. In September 2012 it passed over Northern Europe, Ireland, and North America, after a 3 second bright as day airburst over Finland, and I was adamant it would be back. “The Chelyabinsk meteor was a superbolide that entered Earth’s atmosphere over Russia on 15 February 2013 at about 09:20 YEKT. It was caused by an approximately 20 m near-Earth asteroid with a speed of 19.16 ± 0.15 kilometres per second. It quickly became a brilliant superbolide meteor over the southern Ural region. Wikipedia”. Reports uploaded in 2012 were detailed and consistent with a sling shot orbit. Stories from around the world tell of similar events.

        The loss of the Land of Lyonness between Cornwall and the Scillies may have been drowned around this time and local stories around the coast of Wales are still retold in towns and villages about the sound of church bells under the sea.

      • There is just one problem with the yersinia pestis dogma. At no known epidemy that is well documented has it caused such extreme mortality, nor rapid spread pace.
        Black death spread faster over Europe than a human could walk for instance.

        Ebola would be a crappy theory since it is a too young virus. Best fit to reported symptoms of the Justinian Plague (and the black death) would be Marburg, but that split off in the 1800s from the next in kin on the filoviridae tree.
        Also, both the ebolavirus family and the Marburgvirus family have one thing counting against them, they do not spread well. Against popular belief they are fairly crappy viruses, they burn to hot (kill to fast) and they are bad at spreading between humans.

        Yes, there is ample evidence that Y. Pestis was common under those periods, but so was it throughout the timeperiod, without causing mass death. So, even though many had it, it is not certain that many died from it, even by a longshot.

        Best fit to symptoms described in several bubonic plague episodes fit only one well known illness. And that is influensa H1N1-1918. First of all, influensa is mutating wildly, even in the same family. 1918 was a whacker, but when it returned almost 100 years later it was fairly mild for being an influensa. Nobody knows why. The same goes for other families.
        As one reads the doctors notes from the perhaps first cases in an American fort with ample number of doctors it does not take many seconds to recognize the symptoms described, rapid onset, extreme swelling of lymfnodes, black blotches on the chest and throat, cyanosis, blood cough, cytokine storm, and black lips at the end. And also the part about killing the young and strong first. Almost nobody who developed the black blotches survived, same as for the black death.

        1918 also mutated rapidly during the outbreak causing 3 (or 4) different waves of the illness with 3 distinctly different mortality rates. I mention a 4th that is interesting in the extreme, it had a mortality rate surpassing the 99 percent mark and left a single survivor on an island of 700, the survivor was a great grandmother.

        And 1918 is just one of several waves of influensa pandemies that we have had in the last few hundred years. And we do know that it vacilates between high mortality and being fairly benign. And I do not think that 1918 was the deadliest attack.

        Obviously it could also have been something else like a version of the smallpox, but push come to shove, I would pick our common garden influensa.

        But while being ghoulish we should not forget the 3 big human killers that far outstrip all the other. Measles, malaria and tuberculosis. If memory serves measles took one out of seven in every generation, and tuberculosis one out of three. And malaria still whacks one out of five in many countries. Since we have forgotten measles we have gotten anti-waxers, and that we ever stopped the planetwide TB vaccinations will soon hit us in the arse bigtime.

        • Side note for those unfamiliar….

          The relative success of a pathogen is a combination of ease of spread, and how quickly it kills. A highly lethal pathogen is slowed by not allowing the host to live long enough to spread it far. Lower lethality, or a longer incubation period gets around that.

          Add the modern human convenience of air travel and it’s now possible for pathogens to travel quite far compared to more ancient times.

          BTW, H1N1 and related strains mutate and INSANE rates. Also, the H and the N denote different versions of glycoproteins that the virus uses to get into and out of a cell. If an individual gets infected by two different strains at the same time, and they can mix and match their parts to see what works best. After all, they are mutating engines with the purpose of spreading as efficiently as possible.

          One level up and you have Bacteria. They are known to swap “toolkits” of useful DNA via plasmids.

          • That’s just what they do on their own. The somewhat scary bit is that researchers go out of their way to find and fiddle with versions of these “critters.”

            Not that long ago, I read that researchers managed to recover fully pristine versions of the 1918 H1N1 from the time when it was most virulent. So yes, the 1918 pandemic is still around… sitting in a vial in a research lab somewhere.

            Hopefully in a Biosafety level 4 facility.. but apparently BSL-3 is fine according to the Wiki article.

            • I read that too. I think it was in a book devoted to the subject. I believe they went to Alaska to find a corpse — someone who died while the virus was still inside them (while most died from their own immune response after the virus had been quashed.) I also think they brought home the samples in a cooler on a commercial airline.

            • If that vial’s in Fort Detrick we’re all doomed, I tell ye!

        • Yay me for thinking “flu” when I read that the young and the men were the ones hardest hit the 2nd time ’round. Also, the flu doesn’t have such a long incubation period.
          Plague is spread by fleas, flu by humans.
          Seems that now scientists ask why were rats ever considered to be at blame? Well, that would be the “arrives by sea” bit.
          I’ll propose something with no basis other than “question everything”. What if it were a double-whammy? Rat-based flu + flea-based plague. (Where the flea is the vector for the flu.) This could explain the “comes from the sea” (flu-infected rats incoming) and the rapid spread.
          Plus it fits your double-volcano hypothesis. Double-whammies have to come in pairs, don’t they? 🙂
          (Also, don’t forget diphtheria. I do genealogy and seeing how that wiped out kids — terrible.)

          • “young and the men” point towards a cytokine storm. The strongest immune systems react the strongest.

        • Ebola is a newly discovered virus. It has been resurgent in Africa from time to time in my view. The symptoms and management of the Black Cholera (ebony cholera) in Zanzibar in the 1860s are clearly described by MM Kaye, and in her autobiography she regrets that the libraries built by the British and Americans at that time were destroyed after the colonial input ended. The same details and symptoms were noted in Britain at the source of the Black Death, as being from clothing and material brought by a merchant from the Middle East. The passage of the contagion across Europe from the ports would also fit with people fleeing the disease, as described by MM Kaye, who noted that parts of central Africa were empty because 70% died and the rest ran from it. Its 2 week incubation period is the reason it spreads so far and apparently so fast

          • If it was something out of Africa it was not Ebola. But there are a shitload of other diseases commonly called ‘jungle fever’ that today is not common.

            No, whatever hit back in the justinian and bleack death was airborn.

            • Fleas are airborne (at least some of the time).. I did not go into the symptoms in the post but they included the ‘buboes’ which are characteristic of bubonic plague. (I believe it is the buboes which kill the patient. Draining them gives a chance of recovery.) It was also called something like the groin disease. The evidence that Y. Pestinus was present in the skeletons is quite recent. Prior, it was though this disease was not present before the later middle ages. However, i think it still has not been found any earlier than the Justinian plague. The diseases was certainly very similar to the black death, both in symptoms, spreading, and becoming endemic for a few hundred years.

              A second disease on top of plague is always possible, of course.

              Most of our diseases came to us from living in close proximity to farm animals. They jumped species. And rats are the worst combination, both farm animals and city dwellers.

            • The key piece of evidence that convinced me of Ebola’s rapid spread was its 2 week incubation period before symptoms appear. The television documentary linking it to the Black Death was thorough in its evidence. They reckoned the disease was already a hundred miles further ahead during the before people started becoming ill. It also has a 70% mortality rate if bodies are handled prior to burial. Clothing would transmit it, and it is also airborne for those in close proximity. Disinfectant and hygiene practices did protect westerners in Zanzibar to some extent so their death rates were lower than locals

        • Smallpox is fortunately not around any more. That was a major killer. Measles not that severe, killing mostly weak individuals, but still in action much due to the antivaccin desinformation groups..

          • Measles was a pretty big killer. We have just forgotten about how destructive it was. Normally it hit small children and that raised the lethality a lot.

            Another one that we have forgotten about is polio. But according to the anti-waxers you can cure that with essential oils and crystals. Sigh…

            • I think polio is not very dangerous when contracted in very early childhood, like measles its very damaging when caught later in life (say 15yrs+) and not at all nice even when contracted ages 9- onwards.

              In olden days this was more common (particularly for polio).

              Today both should be considered very dangerous as there are so many immunologically naive people about (clinically speaking).

              I have no idea if maternal antibodies help here.

            • Polio mainly attacks kids, many of them ended up in steel lungs. I just saw a documentary of the last human in a steel lung. He has been in one since age 12. An entire life gone due to the lack of vaccines.
              During the height of the epidemic the US ground to a standstill with schools, libraries and public swimming pools being closed.
              Polio was about as bad as it gets.

          • “Measles not that severe, killing mostly weak individuals …”

            Good grief what a comment. Put simply you don’t have a clue what you are talking about.

            Measles is one of the nastiest infectious diseases around. Its case fatality rate is generally nowhere near that of Ebola for example, but it is far, far, far, far more infectious than Ebola. That said amongst populations already somewhat weakened it can be horrendous. 10-30% case fatality rate anyone? Combine that with the extreme infectiousness and that will 10-30% of an awful lot of people.

            It still kills tens of thousands of people each year. People have been killed and maimed thanks to the fraudster Wakefield and his legions of deluded followers.

            • Measle infections rarely kills healthy individuals but cause more or less severe late complications in a substantial fraction of patients. However, as you say, combined with starvation, other infections or immune deficiences, its another story. And yes it is extremely contagious. Could probably be eradicated if not for antivaccin desinformtion groups…. And by the way, I made my PhD in virology (but not worked in that field for the last 30 years)…

        • Actually there is evidence of the rapid spread of the plague, Carl. Sometime pre-WW1 there was a small outbreak in Suffolk, England. The plague turned to being Pneumonic which caused it to spread easily from person to person and with about a 75% fatality rate. Can’t remember the details but I’m sure a quick internet trawl will pull it up.

          Great article, Albert. A most enjoyable read. Thanks, as ever.

    12. Those strange waveforms we have previously observed on the VES drumplot now seem to have moved to the GRF drum. Looks a bit like the gain setting is temporarily turned up, or an attenuator is switched off. There are quake like waveforms in the beginning and end of the signals which could simply be the impulse response of the filter excited by the transient from the switch. During the signal the amplitude is constant, which fits well with amplified thermal noise.

    13. kinda on topic….. measles and anti vacer’s …. i had the measles before the vaccine was invented and it just about killed me… sick for about 6 weeks and had to stay in a darkened room… every pore of my body had a measle, even my eyes… learned a lot about suffering… Get the kid a shot!!! Best!motsfo

      • I agree…. though I am reticent for the yearly influenza thing. If they can guarantee no adjunct in it, I would be more willing. But I trust them as far as I can spit. I do have partial immunization for Anthrax, but retired before completing the full run.

        Military immunization is sort of strange. Sometimes it’s a shot, sometimes they give you a sugar cube that makes you defecate for a week.

        Am I conflicted? Yeah, a bit. But the vaccinations I do have are for stuff that is far more stable than influenza. No matter what your opinion, influenza is a crap shoot. The virus changes that fast. Mumps/Rubella, got that vac. No chickenpox since I had it already, though shingles vac might be something look into.

        Drove cross country incubating a nasty batch of CMV that I think I caught while tuning an antenna for a friend of my stepson’s. The place was a literal grimy #%@hole. Balboa Naval Hospital didn’t know what to make of it at first. Just before they were gonna do a spinal tap they figured it out and a week later I was released from the hospital. This encounter made me absolutely LOVE that modern medical science has gotten away from having to do the wrist needle to get a blood gas test. That absolutely hurts. Though I have heard that is is still used for some gas tests other than O2.

        As for my near lethal childhood thing, carbon monoxide almost got me.

        • And no, I’m not an anti-vaxer. I’m more of a selective vaxer.

          Fact: Vaccinations DO save lives.

          • The one vaccine that I am against is Chicken Pox. The disease is so pervasive and so rarely lethal that I cannot help but think that it is protective against something else.

            I also have lots of problems with needing a booster after people are no longer school-aged. How is a poor woman (in the U.S.) going to get a booster? We will have more women of child-bearing age getting chicken pox (or going straight to shingles), which means more children with birth defects. Why in the BLEEP would we be doing something that will cause birth defects?

            … And I’ve read that there are more cases of shingles at younger ages. (Yeah, yeah, there are studies that say this is just a coincidence. And there are scientists that poke holes in those studies. Common-sense says this isn’t a coincidence.)

            • common sense, meet quantum mechanics.

              Science don’t got no book with common sense.

              In case that wasn’t clear 🙂 … lets be careful about our science here kk?

            • Pat, which science should I be careful of? The original studies or the analysis of the studies?

              Common sense is often the starting point of hypotheses, so I don’t see why talk of that should be kept separate from talk about science.

            • I have just hit 70 and for a few years I am eligible for a shingles jab.
              I will take it.
              I take all jabs going. Nothing like boosting your immune system.

        • I have a bit of a different opinion about flu-shots.

          First something about the shot itself. The regular flu-shots are as safe as can be. Problem was that the H1N1-shot was speed developed along the lines of how to get vaccination against military threats and was minutely less safe.
          Across the globe a few got nasty long-term side-effects. But the ordinary one does not come with these (or at least far less).

          Secondly, a flu-shot is about 2/3 accurate. Some of the brightest in the field work on prognosticating what to vaccinate against backed by a super-computer. It is probabilistics at its finest.

          If one has high blood-pressure, cardiac problems, respiratory problems, or has a compromised immunosystem one should get a flu shot. If you are young and healthy it is normally more of a do/or don’t thing. On the other hand they are more likely to die from a nasty version.

          And the good part of getting the shot is that even if it is a boom-shot, it will still strengthen your defences partially if you have not had the disease for a few years. Ie, you will get it but get less ill.

          At work we get a flu-shot nurse to come and give us a shot each year for free. About 80 percent take the shot. I can just say that every single year we have been at 70 percent of the national number of sick days. Just imagine what effect that will have on the last line in a company employing thousands… Put in numbers, per every 100 employes we get 30 more work weeks equating to 1200 man hours. Each year. For free, the for free part is due to the not so small fact that we as employers have to pay the first two weeks of sick leave. The minute cost of paying the shots dwarves in comparison.

          If I look at myself, I have high blood-pressure, I am getting older, and I work a lot. For me not having to be bed ridden for a week every other year is well worth being shot-up. 🙂

      • Also had the measles but less than one year old I do not rememberi it and probably I had some antibodies from my very young mom still in my blood and reportedly had a very mild tour. All children in my generation had measles. Vaccination started only 15 years later in Sweden…

    14. https://www.linfo.re/la-reunion/societe/de-nouvelles-images-du-volcan

      Piton is really going for it now, this eruption is much more than anything else it has done in the last decade. Still far from 2007 which was almost at holuhraun or fissure 8 levels for a few days but the fact it has started inflating rapidly in the last few days while already erupting twice at the same time is telling to something being in the works.

      Piton is nothing even close to kilauea in supply rate but even at the reported rate of 1/10 of kilauea that it is still going way higher than most other volcanoes, and piton seems to erupt nearly every single time there us an intrusion so it probably has more individual eruptions than any other basaltic volcano on earth. In the 12 years since its April 2007 eruption it should have been supplied with about 0.3 km3 of magma, which more than compensates for the 0.15 km3 in 2007. None of its other recent eruptions have been very big at all so this eruption might be a while in the making.

      My guess, either this vent gets bigger and we get an ocean entry from this flow in the next week or a new dike opens and an extracaldera eruption happens, both of which will be interesting to watch while we wait for kilauea to recover.

      • 2007 is likley the biggest it can do for now
        There was also a 0,3km3 fast event in Piton thousands of years ago in one of the eroded valleys behind.
        Thats likley the maxium it can do.

        Iceland and Hawaii are indeed 10 times more powerful or more in magma supply
        Iceland does Pitons very largest capability everytime there is an eruption In Iceland
        And its still quality as lower medium sized Iceland eruption…

        The avarge Mauna Loa and Hekla eruption at almost 0,2 km3 or 0,3km3 is as large as Pitons very largest capabilities
        and that Piton only does rarely

        • I think the reason why is because piton doesnt have a big magma chamber like kilauea or the volcanoes in Iceland, which along with its steady supply results in generally small and frequent eruptions of picrite that cant evolve. A shallow small chamber existed before 2007 probably forming between 1986 and 1998 but probably more before 1991 and that fed bigger eruptions in the 2000s which reached the sea and until now those mostly stopped after 2007 (2015 august was pretty big though but slow pahoehoe eruption). Kilauea has a big magma chamber probably at least 10 km3 and likely larger and Icelandic volcanoes especially the vatnajokull volcanoes are 100s of km3.

          Piton might be more active now though than it was in the recent past the wide distal eruptions have been less frequent and more of the caldera is now covered in lava. I have a theory it is at a similar stage to mauna loa in its lifecycle, still very active but not shield building much anymore, unlike kilauea which is in a league of its own.

        • Actually there was also a series of pyroclastic eruptions when it formed its caldera that included VEI 5 events, so it can do pretty big at times, comparable to kilaueas explosive episodes and as big as a lot of subduction volcanoes. This wont happen now though, and I think to go caldera on that scale it needs a submarine eruption.

          • 2007 s Piton caldera eruptions with spatter cones and pahoehoes where very fluid and smooth, almost like Hawaii
            That came quite fresh from source
            2006 and 2007 made very fluid rivers.
            Both Dolomieu pahoehoe filling
            And the large 2007 flank eruption that emptyed the shallow chamber where very smooth and fluid.

            2014 s radial flank eruptions to today been more viscous diffrent temperature and composition of the basalt.
            Coud be older magmas pushed out by New ones. Some in 2014 s and 2015 looked almost strombolian in viscosity
            2015 got good fluid once it pooled inside the spatter cone.
            Still far from as fluid as Piton was in 2006 and 2007
            The current eruption 2018 had quite good fluidity.. still 2007 and Hawaii is more fluid

            • 2007 probably looked fluid from high eruption rate and laminar flow, like kilauea last year. Eruptions in the decade before 2007, but especially 2005 and 2007, were much more vigorous eruptions, 2005 was an extracaldera eruption where the dike did a U turn back to the caldera and both stages of it had high flow, while 2007 was just a massive hole in the sude of everything. The curious and very interesting oart about the eruption niw is that the current dike cant extend easily, it would otherwise have already erupted lower down, so this eruption wont be the final, the fact continued inflation and increasing tremor is still happening despite an entire second major vent (50+ meter lava fountains out of both vents) opening 2 days ago is reminiscent of kilauea in May last year, when the eruption kicked up to mauna loa levels of flow rate on the 18 and yet there was still showing increasing tremor and inflation until fissure 8 reopened and made the rest of the eruption look small.

              No im not saying piton will do a fissure 8 but the tremor and deformation is very high right now, and its not going to be relieved by an eruption at this altitude, either the volcano is going to make a new dike and entire new eruption probably outside the caldera, or it will open even more vents in the area already erupting with consequently more or faster lava flows and then probably do scenario A anyway, definifely something to keep watch.

          • Piton is a much much weaker hotspot than Hawaii or Iceland
            Lavas from Piton are often alkaline and very low in sillica
            lower degrees of partial melting in the mantle.
            That also means they can get very fluid when its hot.
            But the lower temperatures often means higher viscosity

          • Pitons steep upper cone is result of many small and short lived eruptions
            often radial all over. Cinder and spatter cones are everywhere on that upper cone.
            Steep slopes beacuse lavas dont flow far until the eruptions stops.
            There is no well developed rift zones in Piton
            A similar phenomena occurs in galapagos steep round shields
            but Galapagos is a more powerful hotspot than reuinion

      • Piton haves a constant and fairly large magma supply as you says most volcanoes haves far less.
        The volcano likley haves what it needs to substain a lava lake in Dolomieu one day in future.
        A few other subduction zone volcanoes Masaya and Villaricca with far lower supplys haves lava lakes too.
        Pitons upper parts are covered in pahoehoe lava that coud indicate lava lake overflows in the far past. Lava Lakes needs constant supplys and open pipes and hot fluid lavas.
        Piton haves almost all these just lacking that magma chamber conduit summit connection these days. 2006 – 2007 Dolomieu intra crater fillings is the closest it have come to a lava lake in my 23 years of life. Piton almost certainly had lava lakes before .. certainly

    15. I just ran into a fantastic movie showing large parts of Iwo Jima. Really interesting to see so many parts of the volcano, and also interesting to be able to compare directly with the old movie reels and pictures and see how extreme the uplift has been.

    16. Carl there is NO andean volcanoes that with pressed down base gets 72 kilometers tall..
      Andes are grains of sand compared to Hawaii
      I wants to see your VC article how you reasonate about this stuff
      Is it being posted next week?

    17. I have a offtopic question.

      Like many of you here I am sick tired of the sensationalism and invented news stories from the sorts of express uk and daily mail, etc.

      When I google a topic and google news, is there a way to personalize google search results and block those websites? For me, this is trash spam that I wish to eliminate from my search results.


      • You could try a search phrase like volcano -“Daily Mail” . The minus symbol ought to remove the Daily Mail, but remember to use the speech marks around Daily Mail so it is seen as a phrase. To include the Express:

        Vesuvius -(“Daily Mail” “Daily Express”)
        ought to do the trick.

        In reality I think Google may actually ignore the minus symbol and other search parameters if it is paid to put a specific (advertised) result up top. Shame on them.
        Also check out Google Scholar – a very useful version of Google.

        Bing is worth trying, too, using the same search parameters.

        • You could also try to use more scholarly terms than the average dumbed-down media will use. Put the term in quotes. Google STILL will not give you what you want, but usually in the first few hits there will be a small “This does not include the term X. Click here to only get results that include X”.

      • Much of the above, but also consider specifying a particular file type, like pdf. Many times it will spit out links to papers on the topic.

      • Or put the word ‘research’ with the topic in the search

    18. Nice article and I have two questions!

      “Both in 540 and in 1347, the plague followed a major volcanic eruption”. What was the eruption before or around 1347 that I am not aware?

      Why is the year 426 listed as the largest SO2 forcing event, even more than 1258, and also than 540? I thought than 536 was larger than the 1258 event. But what happened in 426???

      Finally, I do not think that Iceland is a culprit. Except for perhaps a large So2 explosive eruption in Katla, Oraefajokull, Bardarbunga or Snaefellsnjokull, that is undiscovered (its possible). The Azores could be a good candidate. It has huge recent VEI5-6 eruptions but they are poorly studied. At least a caldera eruption happened at the 16th century when the Portuguese just started the discovery of those islands (the reports of a mountain very tall disappearing after an eruption leaving the current Caldera Sete Cidades in place. Which was clearly a min VEI5 eruption. So, this went relatively unnoticed in the 16th century, imagine if there was a larger VEI7 eruption around 536…

      • There was quite a large but poorly known eruption in 1345. Not at the 1257 scale but not insignificant. The -426 eruption (note the minus sign: it was long before the year 1) was huge but again, the culprit is unknown. Both are known fro the ice core record but I am traveling at the moment and don’t have the plot handy.

        • I wonder if the climate effects were significant…historic temp graphs are extremely convoluted, some of them actually don’t even have the coldest decades on record on them.

          • Check what the time resolution of those graphs are. I think only tree rings and ice cores get to a resolution of one year or better. If you have one with 50 years resolution, the event would be largely lost. There were no long-term effects on the climate. After 550, things were back to the good old days. Volcanoes cause winter, not ice age.

    19. ?1552166197634


      Yeah this is way bigger than any other eruption since 2007, to light up the webcam that way at midnight from that distance.

      • And it stopped, piton has to have one of the weirdest eruption progressions of almost any volcano, quite often it suddenly stops during the peak of the eruption. In most cases it also inflates before the eruption stops too. I think this is probably not over though, this eruption was not like the other eruptions since 2014. If it restarts I wont be surprised.
        Apparently the lava fountains were over 100 meters tall at the end.

        • Wow… likley the pressure exhausted itself
          water vapour and co2 lava gas geyser at the end
          100 meter tall incandencent part is almost fissure at its birth
          Fissure 8 was a bit taller but not very much in fountains

          Still Fissure 8 had an absoutley insane supply and rate at constant through the summer

          • https://www.facebook.com/cbphotographyHawaii/photos/a.1984084871626343/1984085008292996/?type=3&theater
            Fissure 8 near its peak in constant eruptive output. ( not the boosts in flow supply as caldera collapse vent fast at times )
            120 cubic meters a second and very fast and fluid smooth flow regime.
            The fissure 8 lava channels became a boiling foamy mess with turbulent flow and huge dome fountains in the vent.
            At that advanced stage as you say its very much like a broken pipe rather than a lava geyser. The vent enlarges and fountains dissapear and becomes upwellings.
            A real cascading river flood of highly fluid basaltic lava.
            Souch very fast eruptions rarely lasts long as magma supply cannot keep pace.
            Still months of this are very impressive and it will only happen more and more often as Kilauea reaches its main shield boost.
            Fissure 8 was really impressive dwarfing the USGS volcanologists as they visited the raging channels near the vent cone: https://www.youtube.com/watch?v=au9yLUv8o04 but the colour in that video is poor. Its possible to see how very gas rich fissure 8 s lava was by the forthyness of it.
            I visted fissure 8 in christmas and found brown reculites everywhere another signs from the high lava fountains and extreme gas content of its lava.

            If this happened in Reuinion with its rather steep slopes.. the lava woud reach the ocean in less than a day or around a day.

        • yes I know, it stopped erupting literally about an hour after I posted it anyway though

    20. One of the best articles I know here on VC, thanks for the time Albert!

      To have some distraction from all the fanboying on Kilauea: There were quite some deep quakes at Bardarbunga, where do you guys find the inflation plots? I need to save those eventually. More interestingly there was a deep quake at Kistufell as well! Also Askja had a 2.9 and other minor activity but I reckon this was tectonic.

    21. Kistufell is an incredibley strange volcano
      Sitting right on top of the eastern rift zone and the Icelandic Hotspot
      Its weird it have not become a large central volcano like Grimsvötn or Kverkfjöll or Bardar
      Vonarskråd is just as strange
      These two should be like Grimsvötn

    22. Due to atmosferico circulation, climate could be very different in diverse climatic zones: this has been one of the warmer and dryer winter in northern Italy in the last 50 years, on the contrary north the Alps there have been meters of snow and cold…
      We now have flowers and blossoms like in advanced april…

    23. My memory fooled me on my candidate. It did match another lost eruption in a completely different century though.

      So, I went spelunking. And came up with naught. But I could remove a very large range of volcanoes.
      The Azores are cleared, nothing on that scale there. Nothing onland, nor in the water.

      Neither is there anything even close in size in Kamchatka (disregarding the possibility of a double-tap here).

      Obviously there is nothing either in Iceland now that my favourite suspect was cleared.

      So, if we go to Alaska, is there anything obvious there? Well no.

      So, that sent me out into the ocean galumphing about. My search parameters was looking for something close to the surface, or barely above surface. Anything deep would not show up like ash trails. Basically we are looking for a landscaping artist with nasty explosive tendencies.

      Turned out those are not that common. Either we do not know anything about their behaviour, or they have not erupted for a very long time. Well, except two surprisingly familiar culprits. One went caldera at some point and has since then rebuilt. The other either extrudes lava dome islands and blows them up, or cause ash galore.

      1. Nishinoshima. The remnant island is dated to 10 000 years, but it is just a remnant out of a pretty sizeable caldera event. It builds an island, has a large eruption, then goes Krakatoa. And it definitely has the umpf and stamina to do something memorable.

      2. Bogoslof, the Alaskan landscaping artist. Known to have formed historically sizeable islands in short notice in the form of extruded lava domes (one was 400 meters above the ocean), to then blast them into smithereens. An old volcano that is just to violent to create anything stable. It is not a far stretch to think that it grew just a bit too big, waited for a hundred years to pick up some extra umpf and went heywire all over the place.

      Obviously I do not have a single shred of evidence except the characteristics, and any evidence would be blasted to Kingdom come by now. But they are not bad as candidates.

      There is also Kikai, it is dated at around 100AD, but how well dated it is, that would be hard to say.

        • Yes. I am not at all sure that Bogoslof can cough up a furball of that size, but Nishinoshima has done it at least once that we know of. But the Japanese never bothered with dating the caldera-event before Nishinoshima destroyed any evidence back in 73. And a caldera that is nine by nine km would fit the bill of a minimum mid vei6.

          • Nishinoshima may be a little too far south at 27 degrees. Bogoslof had occured to me too. Any island location where the tephra is lost under water would be an option. If on-land, it is likely an eruption we already know about, but wrongly dated and with the wrong size (not unusual – se ilopango). I am disappointed that the Azores show no events that fit.

            • Ann Gibbons erroneously in her book blamed Iceland by the way, but I guess you knew that. 🙂

              I think my spelunking have found the volcano in question. I will get back on which volcano I think it is. And it connects a missing piece in your otherwise enormously well researched article from a historical point of view.

            • My point about Ann Gibbons is that if I can’t find a major eruption in Iceland at that time, it is unlikely that there was one. And you can be sure that I have looked at every single volcano on Iceland, famous or not, to find a smoking gun for 536.

            • Any chance of a submarine eruption south of Iceland, at a time the wind was away from the main land? Clutching at straws a bit..

            • Supporting the straw fix, maybe the Vestmannaeyjar area?

              Anyone know how old they are? If the islands were still messed up and recovering, it would support the idea of exiling someone there if you were really pissed off at them.

            • Nope, nothing of that size out there. Nor to the north of Iceland.

        • Could Myojinsho (Beyonesu Rocks) be a reasonable possibility? It has an 8-9km submarine caldera at 1000m depth. No data on when it formed.

            • What about its near neighbour, Myojin Knoll? 6-7 km diameter caldera, very youthful appearance, high point on caldera rim at 360m depth -but pre-caldera cone would have been much closer to the surface

          • @mjf. Look for something near but below the critical point of water in pressure. Too deep and you might get a nice pumice raft and not much else. 1000 meters might be near the depth to start flashing the water to steam, but the deeper it is the less violent the surface expression is going to be.

            • 1 km is too deep. Of course, originally the mountain would have been higher and the explosion closer to the surface. If the eruption was from an island, I think we are looking for a mountain that used to be above the sea. It should be no deeper now than a few hundred meters

      • How about Grimsvötn?
        No ashlayer in the icesheet from that age?
        Grims huge supply should be able to do this stuff
        Think 2011 on gaumpf humpf steroids

      • After all its inside Grimsvötn all the Icelandic Balrogs are housed in south magma chamber caldera

      • I still say that Mauna Loa checks all the boxes and should be the leading candidate.

        There is confirmed and documented significant (multi km3) activity around 1500 years ago.

        An extended (or successive) VEI 3-4 outbursts from ML over a period of weeks or months would have dumped many times more sulfur into the UT/LS/jet stream than any VEI 7.

          • It mostly doesn’t, but it is in a unique place in the eastern Pacific where it doesn’t need a plume to reach that height.

            9-10 km is probably more than sufficient.

            This is the 20 year AVERAGE jet stream position

            The jet folds down the tropopause at the ITCZ.

            At 15 degrees North in the Western Pacific (Pinatubo) ….no argument….needs to be stratospheric.

            20 degrees North in the Eastern Pacific (Hawaii) ….who different ballgame.

            It is odd to me that practically nobody blinks at the idea of the plume from Laki entering the UT/LS. I think that everyone assumes that because it rains a lot in Hawaii that it is closer to the equator.

          • It can’t. I think the idea is to reach the jet stream at 8km, and get the long-lasting effect from a long-lived eruption. There are some issues with this. Mauna Loa is quite far south, within the tropics: once the sulphate gets into the tropical jet, it will spread south as well, while the data suggests it didn’t (southern tree rings do not see the 536 event, only the 540 one). The sulphate will probably only last weeks at this altitude, raining out and dropping out. It is not clear this will give a long-lasting veil at large distances: it may become intermittent, changing with the jet stream. Laki worked like this, but it affected mainly the Atlantic basin. I am not sure why Hawaii would produce so much more sulphate than Iceland – even Mauna Loa would be hard-pushed to surpass Laki in volume.

            However, a long-lived eruption is worth considering.

            • Rarely mixes southward from Hawaii….not unheard of…but the exception. Mostly it looks like this…..

              …..or this….

              Significant eruptions in Hawaii easily interact with the upper level winds. A sustained (or intermittent) VEI 3-4 in Hawaii easily sends a significant plume high enough for dispersal to the east.

            • Hawai’i is at 18N: the jet stream only just gets there, and only some of the time. And because of the short life time of the sulphate in the wet troposphere, you need much more sulphur than in an explosive eruption to maintain a dense haze for 18 months. A quick estimate based on life times suggests ten to twenty times as much sulphur will be needed.


            • Hawaii literally just had (well probably is still having) a very long lived voluminous eruptive episode that lasted for decades and involved multiple km3 of lava and also ended with a 1 km3 lava flood, and nothing bad is being linked to it in the west of the world. Mauna loas activity was 2.5 km higher up but I dont think that is going to make much difference in this case.

              The 1500 years ago activity at mauna loa was like pu’u o’o not like the eruptions it does now but continuous, hawaii has the highest magma supply on earth and even that can only sustain rates around 10 m3/s which is the average of pu’u o’o. Basically for whatever reason for a few hundred years mauna loa took the plume from kilauea and had a short return to its glory days of shield building but it wouldnt be anything much more than what has happened in the last 500 years at kilauea and if last years eruption didnt do anything to the environment I doubt mauna loa will either even if panaewa was 7 times bigger than last years eruption.

            • High (very high) eruption rates would be needed because the sulphate (over Europe!) needs renewing every few weeks. Pu’u’O’o was indeed far too slow.

            • 1. There are many confirmed and documented examples of eruptions in Hawaii reaching jet stream levels. Some are from relatively small events.

              2. If even small eruptions in Hawaii can interact with the jet stream the larger ones must have. A sustained (or intermittent) multi-km3 VEI 3-4 is well within the historic capabilities of Mauna Loa (and Kilauea more recently).

              3. It is absolutely known that around 1500 years ago, Mauna Loa had multiple multi-km3 outbursts.

              Just sayin’….

            • Yup Hawaii can do slow eruptions that last for decades or centuries
              If we look at Mauna Loa in Google Earth all the light Brown stuff is pahoehoe that totaly dominates Mauna Loas flanks

              Thats signs of previous slow constant lava flow activity feed by high standing lava lakes in summit feeding lava tubes.
              Mauna Loa did that non stop for decades or even many 100 s of years at constant slow pace.

              In Google Earth the flanks of Mauna Loa are totaly dominated by pahoehoe from constant slow effusion.

              The Darker channelized flows are Newer high eruptive rate Aa flows from high rate fissure rifting events

            • In other words something like this….. but lasting a few days or weeks or longer or intermittently spewing like this every few weeks over a period of a few months.

            • The Qk3 layer of Kau Basalt is dated from around this time. That’s a lot of lava and most of it originated at the summit.

            • Mauna Loa is still too far away from Europe. The Pana’ewa eruption dated very roughly around 500 AD, lets be very generous and since we don’t know how much lava might be hidind in the lava delta say it produced 6 km³, and lets assume it managed to erupt continuously for 1 year (which is what the haze has been reported to last in Europe). Laki had intermitent effects over the areas of the Atlantic, why would the smaller Pana’ewa eruption have such strong effects as far away as Europe? the haze also seems to have been rather sustained.

            • When Mauna Loa was at her very peak of activity she coud produce a fast lava flow 12km3 fissure event in same speed as Laki. That woud inject sulfur in the upper tropospause.
              Many souch events happened under her lifetime.
              Certainly happened long ago in Hawaii knowing its insane magma supply rates and rather large magma chambers and previous large lava flows like Panaewa.
              Souch a large fast basaltic eruptions glow woud be seen far and wide over the Islands and produce spectacular ocean entries

              Think 1950 on steroids and much higher eruptive rates

            • BadWolf those summit eruptions you describe were similar to Pu’u’o’o, slow eruption rates they end up being very voluminous but might have formed in different episodes over the course of centuries.

              Jesper there is no reason to think Mauna Loa was ever capable of that, hawaiian magma chambers seem to store a few km³ they can release fast if emptied in one go, usually by eruptions low in the rift zone.

            • Wolf I just want to say that there was in fact a historic eruption of exactly the description you talk about referring to something like mauna loas 1984 eruption but faster, much more voluminous and longer lasting.

              It happened last year…

            • Albert

              ML summit is at 19 degrees 28 mins north. Sounds small, but even just another 100-150 miles farther south matters. Much less opportunity to interact with the jet. I have looked for research on the Qk3 flows but have not found anything published other than Pana’ewa eruption dated very roughly around 500 The largest Qk3 flows cover about 30% of ML and ran into the ocean on all sides. Plus the jet moves and stays farther south as the NH cools.


              The crater at #8 is what…100 meters wide. Last year’s eruption was a speck compared to what is possible (and probable). The summit craters at ML and Kilauea are hundreds of times bigger. These areanot gentleggiants …they are beasts with documented histories of high volume and explosive activity.


              Lava from ML summit eruptions tend to be hot and fast. Not slow and puuoo-ish. It ran down all sides 40-50 km to the ocean. The south flank eruption covered most of the west side of Kilauea. Combined the Qk3 flows could easily have been several dozen km3 over a relatively short period.

            • Kilaueas summit formed through collapse the same way it did last year it is not an explosion crater, neither is mauna loas, and actually neither is almost any crater that big full stop on any volcano.

              The biggest known explosive eruption in hawaii was the pyroclastic phase that preceded the pu’u waawaa trachyte dome eruption from hualalai and it was a few km3 which is decent VEI 5, and that happened about 100,000 years ago. Some of kilaueas explosive eruptions about 1300 years ago might have barely reached VEI 5 which is a 0.3 km3 DRE summit eruption, about 3 times bigger than 1959 erupted in the same time, or a bit bigger than the total volume of the 1790 summit eruptions but entirely as one short and very powerful eruption.

              Mauna loa has never done something like that even, its biggest/most intense summit eruption we have observed was in 1949 and lava fountains were 300 meters high but this is pretty normal for basaltic eruptions of large scale. 1949 was the only eruption like in the last 1500 years to do this too, it made a pumice field downwind, but no other pumice fields are visible around its summit.

            • Hualalai have then produced mostly very alkaline basaltic flows
              The flows of 1800 s where very mafic and very sillica poor
              And rather very fluid.
              ”Nyiragongo effect is there”
              Rather steep Kona slopes and sometimes very very very fluid lavas

            • Summit eruptions of Mauna Loa can be slow, it just hasn’t shown that face much lately. The only historical eruption to be this way lasted between 1872 and 1877 when an overflowing lava lake gradually filled a recent summit collapse that most likely took place in 1868. The summit flows of Qk3 are made of sheets of pahoehoe (typical of Puuoo-ish eruptions), no lava channels or lobate aa flows are visible (typical of more vigorous activity). These summit eruptions are thought to have been fed by sustained activity at the summit for long periods of time (decades or centuries), one of these may have culminated in Pana’ewa. Mauna Loa and Kilauea are similar in activity when they peak…

            • There are many examples of jet stream interaction. Here are a few more. I can go on.

              Thus, the mechanism is confirmed.

              I am not suggesting that there was a massive VEI 5-6 thing at ML. Quite the opposite. I am suggesting that the flows designated Qk3 that originated at the summit were likely from hot fast moving lava which erupted of over an extended period of weeks or longer.

              That type of extended activity from the summit would have released potentially hundreds of Mt of SO2 that could easily spread across the entire NH within weeks.

            • Plus, the two biggest known and documented “dry fog” events (aka 1783 and 939) were both caused by a dense, high volume, much lower altitude (upper troposphere / lower stratosphere) atmospheric sulfur loading from basaltic eruptions.

              To my knowledge there is no known significant “dry fog” associated with any stratospheric explosion event….even Tambora. The stratospheric veil caused by Tambora is sometimes loosely refereed to as a dry fog but these stratospheric veils are very different from the 1783 and 939 choking lower altitude dry fogs.

              536 was one of those low altitude choking dry fogs. It was likely also caused by a dense, high volume, much lower altitude (upper troposphere / lower stratosphere) atmospheric sulfur loading from a basaltic eruption. ML is a possibility that should not be ignored.

              As I already showed, especially in the winter, the jet stream can easily carry a plume from Hawaii to Europe within a week or two. If the source of the plume was persistent over weeks or longer, the entire NH could get fogged in pretty quickly.

            • The difference between low and high altitude fogs/haze is important and is normally not clear from the descriptions. The 536 notes does not say that people had difficulty breathing. (Some talked about moisture which it definitely wasn’t.) Krakatoa was an example of high altitude haze. There are no reports of coloured suns in 536 (or 540) but that was not see much in Europe after Krakatoa either – most reports were more southern.

              Low altitude sulphur is very intermittent.

              I think hundreds of megatons of SO2 won’t do. It must have been much more than that,

            • The most worstest baddestest case scenario of all would be a double tap from a stratospheric veil caused by even a modest Pinatubo-sized VEI 6+ over the top of a 1783/939/536 -type lower altitude dry fog.

          • Several hundred Mt is not out of line at all.

            Qk3 Rough Estimate of Potential SO2 output. (Conservative)

            Total ML Area (km2) 5,271
            % of ML covered by Qk3 Flows 33%
            ML area covered (km2) 1,739
            Qk3 Average Depth (m) 20
            Qk3 Average Depth (km) 0.02
            Subaerial Volume (km3) 34.79
            % of Eruption Drained into Ocean 33%
            Total Erupted Volume (km3) 46.27
            SO2/ km3 (Mt) 7.5
            Total Mt Potential 347.02

            The surface Qk3 flows (and Qk2 flows before that) are not hypothetical “what could it do” or “it has never done this or that”…..they exist and are massive.

            • Yes, you are right. The ‘ice core’ unit is Tg which had confused me. But only a fraction would have made the jet stream, and you need much more with a lower altitude haze than with a stratospheric layer because it needs renewing every few weeks.

            • Fair point….


              Remember to reverse the arrow for the upper level winds in Hawaii. They blow opposite direction of the low level trade winds.

              …..Updated Rough Estimate

              Qk3 Rough Estimate of Potential (Conservative)

              Total ML Area (km2) 5,271
              % of ML covered by Qk3 Flows 33%
              ML area Covered (km2) 1,739
              Kilauea area Covered by Qk3 (km2) 250
              Total Land Area Covered 1,989
              Qk3 Average Depth (m) 20
              Qk3 Average Depth (km) 0.02
              Subaerial Volume (km3) 39.79
              % of Eruption Drained into Ocean 33%
              Total Erupted Volume 52.92
              SO2/ km3 (Mt) 7.5
              Total SO2 Potential (Mt) 396.89
              Lofted % (Special 50% Hawaii Discount) 50%
              Potential UT/LS SO2 Loading (Mt) 198.45

              I still think this is a conservative estimate. Would have occurred periodically or as a more or less constant load for some days/weeks in the cycle.


              This is conservatively:

              ~10X Pinatubo
              ~4X Tambora
              ~2X Laki

            • Image did not post. Here’s another version of the same scheme.

            • It generally seems to be underestimated what kind of eruption is needed to get such severe consequences for the climate as described in Albert´s post above. A big whopper (or a double-whopper) is needed to get as much sulphur high into the sky. Also do keep in mind the place of the injection, northern or southern hemisphere. A southern hemisphere eruption would need to surpass humongous eruptions that happened on the northern hemisphere. Us as a community did not manage to come up with more than 5 to 10 possible culprits here.. Happy to prove me wrong but I just cant picture an effusive eruption at the southern hemisphere to be able to pull such a blast.

            • I would still like to see an explanation to why mauna loas ehield building eruptions cause global climate imbalance while kilaueas equally big if not bigger ongoing phase that just had its biggest eruption in the entire series is doing absolutely nothing at all. As you pointed out it is rather easy for hawaiian eruptions to reach the jet stream there, I would have no doubt that the massive fountains of 1959, 1960, 1969 and early pu’u o’o would have easily made convective currents that reach that far, but they didnt do anything to the climate, only last years eruption changed the climate and it was very localised to the southern part of the island.

              As also said, the Q3 flows are like pu’u o’o, a slow tube fed pahoehoe eruption, the low eruptive rates are obvious by the fact that only on some sides did the flows actually reach the ocean and many historical fast flows are longer (1859, 1880). They are not like 1950 or 2018, only panaewa was like that and it is still too small to be a reasonable candidate for the 536 event. Mauna loa is steeper than kilauea near its summit so the same eruption will make longer flows on mauna loa than kilauea. Anyway, if the q3 flows are about 50 km3 by your estimate, then if they erupted for about 500 years that is an average supply of only 0.1 km3 per year which is half what kilauea was doing for pu’u o’o. Kilauea also appears to have smaller eruptions because its eruptions happen closer to the ocean and so basically all large eruptions send most of their volume into either the ocean or get trapped in a caldera like 1959 while on mauna loa in most cases I think the volume of lava on land is probably about 90% of the total at least (1950 might be an exception).

              Based on the supply rate from the hotspot, since 1500 years ago kilauea should have received about 300 km3 of magma, a lot of this will end up in the deep rift, but about 200 km3 has probably erupted somewhere, most of it probably as the slow pahoehoe eruptions from the summit that had to fill the powers caldera *which was a lot bigger than todays caldera basin) and a lot of the remainder is through partial caldera filling like 1790-1924. Apart from the aila’au eruption which sent flows north a long distance, all the pahoehoe eruptions on kilauea have sent flows to the ocean within about 15 km of their vent, which is enough that for most of that flows duration the lava is flowing to the sea unobstructed and being lost. 50% of the true volume of pu’u o’o was lost this way, its on land volume is about 4.5 km3 but its real volume is about 9 km3. Last year is 0.8 km3 on land but the amount underwater (lowest point 2018 lava was found was nearly 2 km deep) probably pushes the volume up well over 1 km3 and that lines up better with the eruption rate too. The total volume of all the eruptions since 1500 years ago that is still on land is probably about 100 km3, with 100 km3 total being in the ocean on the south flank, and another 100 km3 in the deep rift where it is probably evolved and like fissure 17 lava and not really easily eruptible now.

              By the way yes 100 km3 of magma can EASILY fit in the deep rift of kilauea. The orange is 100 km3 in volume – 8 km deep (decollement fault to 2 km below surface) x 750 meters wide (much less than the actuall rift width) x 25 km long (mauna ulu to heiheiahulu more or less).

            • TJ

              1. Hawaii is clearly located in the NH.
              2. Not remotely underestimating the scale of atmospheric load needed to impact weather.
              3. Not trying to prove anyone wrong. Just presenting some facts and a supporting theory.
              4. Hawaii is not always effusive. It also spends a lot of time in a more rambunctious state.


              Lot to unpack there and I will do so tomorrow. Short version….the mechanism absolutely works for Kilauea too.

            • More detailed reply.

              First, the premise of my argument is that Hawaiian volcanoes can potentially create temperature altering atmospheric sulfur loading not that they always do.

              As many have pointed out, there are complicating factors that all must be taken into account. I have attempted to address as many of those factors as I can think of but, also based on feedback, I also know I still have much more work to do to make a compelling case.

              The size of the plume and the time of year are probably the two leading factors.

              Yes, the massive fountains of 1959, 1960, 1969 and early Pu’u O’o would have easily made convective currents capable of sending gasses up 8-10km. Same with the 1984 and 1950 ML and pretty much every documented eruption in Hawaii since 1823. In fact, it is clear from the data that is actually fairly routine for Hawaiian eruptions to send up plumes to jet stream altitudes.

              The main reason that we have not seen larger impacts in the modern era is, for the most part, they were just so small.

              For all the reasons that Albert pointed out yesterday, for this mechanism to work, it requires a much much larger atmospheric load. An occasional .25 km3 outburst is certainly not sufficient. It requires a more significant plume sustained or intermittent over days, weeks, or longer. Even something like a Pinatubo-sized 20Mt from Hawaii would likely have minimal, if any, meaningful impact at LS/UT altitudes.

              Timing also matters. A Hawaiian gas plume from roughly between October and May has a much better chance of making it into the jet stream. The same plume in June-August would struggle to get there days and even then would find much lower velocities.

              Regarding eruption rates, I am assuming that the main and biggest Q3 (and Q2) flows were primarily ‘a‘ā lava. I think ML 1950 is the best modern example.

              Back to Kilauea and its potential impact. One thing I have attempted to do (assuming that this mechanism is valid) is to match up older known (and Much MUCH larger) Kilauea flows and eruptions with ice core records and “unknown” volcanoes. I have a few notes on this, but nothing I am ready to discuss just yet.

            • There are no ‘older and much larger’ lava flows on kilauea, the last 70 years has been one of its most productive eruptive episodes in its recent history. Last year was probably the biggest eruption on the island since panaewa. Puu oo was also the largest east rift eruption in at least 700 years and probably over 1000 years.

              If you mean the aila’au lava flows those were not bigger than puu oo the lava just had to flow further. Maybe the eruption wasnt a mirror of puu oo because it flowed further than puu oo could reach in 2014 but in any case this eruption is seen as more impressive only because for some reason HVO has associated it with causing the collapse of kilaueas caldera. It certainly didn’t do this, mostly because gravity doesnt work that way, and more than likely the aila’au eruption didnt actually last 70 years but maybe 20-30 possibly spread out over more than one eruption, and most likely the eruption was already long over by the time that the actual caldera collapse happened (the real culprit was very probably a massive LERZ eruption around 1510, some 40 years after aila’au). Kilauea easily does multiple km3 eruptions, but it doesnt do them like iceland does, until last year all eruptions in hawaii over 0.2 km3, apart from mauna loa 1950, were long duration tube fed pahoehoe eruptions. Last year was the first recent eruption of its type to reach 1 km3 without at any point being dominated by slow effusive activity.

            • Yes….‘Ailā‘au and a bunch of other known and big events before, around and after 1500 (albeit not witnessed).

              Much more powerful eruptions occurred in the more distant past.

              One large explosive eruption at Kïlauea’s summit 1,000-1,200 years ago sent golf-ball-size dense wall rocks to the south coast of the island, 18 km (11 miles) away. One block 24 cm (9.5 inches) across and weighing
              4.43 kg (9.7 lbs) fell 5 km (3 miles) from the vent.

              ……If an event on this scale had happened in Iceland or Italy, there would be a million books written about just that one eruption.

            • All I am suggesting is that:

              1. If you buy into the fact (which actually appears to be quite clear from the data) that is actually fairly routine for Hawaiian eruptions to send up plumes to jet stream altitudes, then

              2. It makes sense to take a fresh look at possible instances at Kilauea and Mauna Loa where the plume could possibly have been large enough to have impacted the NH in the same way that Laki and Eldgjá did from their basaltic origins.

              The timing and scale of the various Qk3 flows is just one example of something that I think should not just be dismissed.

              I also understand that this opinion is not widely supported …..(or at all)….yet. hahaha 🙂

            • That eruption 1300 years ago was probably a borderline VEI 5, like grimsvotn 2011, and no that is not going to change the climate. It might be partly responsible for some really old chants in the hawaiian folklore but that is about it. 1959 was actually not much smaller, and in hindsight it has been recognised tgat it was very close to going plinian but the pressure sebt a dike down the rift instead because if the high altitude about 1 km above sea level, while the lower kulanaokuaiki tephra was likely from a vent more around 700 meters in a deeper caldera. 1790 was also comparable, the thickness of the tephra around the summit is very significant over 10 meters in places and most of thst is from 1790, that eruption was also a plinian borderline VEI 5 and no doubt that one was well observed. Given the similarities between now and when those eruptions happened we might get to test that theory out in practice soon but its not going to change any climates except the one concerning kilaueas gentle reputation.

              For the record in DRE a VEI 5 is about 0.3 km3 of magma, 1959 has a known volume of about 0.07 km3, about 1/4 of that, but adding the volume of 1960 would bring it up very close to that, had all the magma of that episode erupted at kilauea iki I think it would have got pretty scary but obviously the pressure was too high. 1790 I would be surprised if it is anything less than 0.2 km3 DRE, its eruption effected the whole summit, obviously the main vent was in a crater lake but other vents erupted on the ring fault during the ash eruption and another on the southwest rift.

              Yes kilauea can do some big pyroclastic eruptions but nothing hawaii can do will alter the climate outside the islands, and anyway if iceland cant manage it in favorable conditions with a lava eruption much bigger than hawaii has ever done then I think your arguments are a moot point.

            • I am not remotely suggesting that the 1,000-1,200 years ago event was, on its own, large enough to have impacted NH temperatures. I just nicked that description directly from a Don Swanson paper as just one example of a much more powerful eruption that occurred in the more distant past.

              What I am clearly suggesting, however, is that if you buy into the mechanism there could easily be some additional sulfur spikes in the Greenland ice that could have been related to Hawaii activity (especially if it occurred in cooler months).

              Only the largest of these would have the possibility of any significant temperature NH temperature impact. But, as Pinatubo showed, some impact can occur from even modest sized sulfur loads. Pinatubo’s 20Mt of SO2 was first spread across the equator and only months later was dispersed across the NH and SH. For example, a NH, temperature- impacting 20Mt cloud dispersed in 5 separate 4 Mt tranches or continuously from a sustained Hawaii eruption (corresponding to ~ 3-4 km3 eruption is easily within the relatively normal scope of both Kilauea and ML.

              It is those scale of eruptions (potential to impact NH by .5 to 1 degree for a year or so) that I suggested should get another look.

              The 536 event was on an entirely different scale. That was not just temperature-impacting. That was from a climate-crushing, dense, sustained, 18 month-long cloud over the NH.

              I still say that the Qk3 flows should be considered as at least a possible 536 candidate for further research and analysis.

            • There is always something to consider, that being how fast the eruption was, and most big hawaiian eruptions are slow (meaning decades or centuries), that includes Mauna Loa too (and most of the flows of the Qk3, particularly the ones coming from the summit). Yes, Mauna Loa is not always fast, the 1880 eruption almost reached Hilo (it destroyed 1 house) but it took the flow 9-10 months of slow advance to get down there. There are exceptions, eruptions from the SWRZ of Mauna Loa have been generally intense (1950, 1868), the eruption of past year was also very fast considering its large volume so I would recommend studying the climate impact of that eruption first or of other recent big events (which their date is actually known) 1790, 1840…

            • Definitely trying to do some eruption / ice core matching to known Hawaii stuff. It’s not easy.

              Back to ML.

              1880 was entirely a slow moving pahoehoe flow.

              The Qk3 flows are mostly a’a. The flow south of ML summit even covered a huge section of Kilauea all the way to the ocean. That must have been an impressive sight to see towering fountains at the top, the whole side of ML glowing + the ocean entry.

              I just don’t see how the Qk3 a’a could have just “slowly” rolled out over that much area and distance. It must have been a more rapid process of weeks or a a few months at most for hot a’a to cover that much area and travel that far.

            • Looking at the most detailed data set from the (Sigl, et all) research, and initially focusing on the dates since 1823, preliminary there appear to be some elevated sulfur levels in the Greenland set in the 20th century that appear to be pretty well correlated to known periods of heightened activity at Kilauea including 1968-1974, 1959-1961. The 1840 eruption was short and in May. Less likely to have been carried to Greenland.

              Notably, however, there are also relatively large spikes in 1832 and 1836 that could easily be Kilauea. It is known that about 3 km3 of lava erupted to fill the caldera after 1823 and before 1840. So that fits too.

              There are small bumps in 1984 and 1950 that could easily be ML.

              The bigger items like Pinatobo, Novarupta, Krakatoa, Laki, Tambora are pretty easy to spot.

              The other elevated periods in the middle of this period still need more work to tag.

              Initially, however, this seems to fit. There are sulfur spikes in the Greenland ice that do not align to any other known eruptions but that do appear to line up with some known eruptions and high fountain activity in Hawaii.

              Anyone else interested in pouring over the detail, here the link to the paper and Greenland data file.



              Tab 12 has the most detailed data.

    24. a good or a bad sign five quakes in 20 hours at the atlantic ridge?

    25. With the eye on Mauna Loa. The GPS instruments show that the area near the caldera has begun to show accelerated drift in the past few weeks. This is seen on MLSP2, PHAN and PAT2m but they are moving in somewhat different directions. GPS’s further down the slope (AINP, KHKU) show little effect. There is also slight inflation near the summit.

      It seems consistent with a small magma recharge, at or near the caldera.

      • Looking at GPS stations near Mauna Loa, I found only 4 or so with data out of about 12 nearby stations. Must be behind maintenance since the shutdown? Anyway, I made a quick sketch of the movement of the available stations “since Fissure 8”:

    26. https://m.facebook.com/photo.php?fbid=757894734581361&id=100010825231980&set=a.193142847723222&source=48

      Nyiramuragira ( Nyiragongos sister volcano )
      Continues with filling up her inner caldera pit.
      The photo shows a very small lava lake thats been there for over a year. The once deep 2014 pit is now filled to the brim with lava lake overflows.
      Patrick Marcel was able to hike out on the filled up pit and watch the tiny lava lake in action.
      The lava is a Basanite ( alkaline very sillica poor basalt )
      And seem rather crystal rich in the video he posted here: https://m.facebook.com/story.php?story_fbid=764633497240818&id=100010825231980
      Still very fluid coud also be the extremely high gas content that makes it forthy and rough.
      Nyiramuragira is likley entering a phase of long lived lava lake activity, before its been rather large rifting eruptions. The lava lake activity came back in 2014.
      Nyiragongo and Nyiramuragira are africas most active volcanoes with in the Albertine Continental Rift and Local hotspot mantle plume.
      They are known for their hot alkaline and very very sillica poor magmas
      Nyiragongo does ultrabasic Nephelinites
      Nyiramuragira does basic Basanites

    27. So skimming through google earth’s volcano overlay, I tried to get some potential candidates for the 536 eruption. In doing so, I looked for volcanoes with decent sized calderas or collapse structures that feature younger looking erosion patterns, and then overlaying that with researching whether the big eruption was from a well-known and researched time period. I found a few potential candidates.

      1. Yunaska: From Alaskan Volcano Observatory – “”The eastern volcanic center, to which all recent Yunaska volcanism has been attributed, has been described by Nicolaysen and other (1992) in preliminary reports as a large shield volcano topped by two overlapping calderas. No age has been reported for caldera formation but the fresh morphology of the younger caldera and the non-glaciated nature of the associated pyroclastic rocks suggests it is at least Holocene in age” . FWIW, the caldera looks very young and is of a decent size (larger than Tambora).

      2. Okmok: Okmok has a huge caldera (10km across) that makes it more than big enough for this eruption. Amazingly, there are two of these similar sized caldera forming eruptions that have happened in the past 10k years from Okmok, which is somewhat mind-boggling when you think of the amount of input it would have required to have such an eruption. Nonetheless, the more recent eruption is generally thought to be around 2000-2400 years ago, but the dating on this came from charcoal dating back in 1987. Not an expert on dating, but I have to imagine there is a possibility of dating error here.

      3. Akutan: From the GVP – “The 60-365 m deep younger caldera was formed during a major explosive eruption about 1600 years ago and contains at least three lakes.”. That puts the date very close to our target range already. With that said, the caldera is more Pinatubo sized than anything else, leaving doubts as to whether the eruption was large enough to cause the effects seen in 536. Could be a potential double-dip candidate however.

      4. Chirpoi: Chirpoi is part of the Kuril islands north of Japan. It has a 9km wide caldera that is largely submerged. Furthermore, it could potentially be relatively young, and the age of the caldera is essentially unknown. As a result, could be a potential candidate.

        • Okmok date and magnitude lines up fairly well with the #3 event (44 BCE) from Michael Sigl et al.

        • INSAR image of Yunaska. The dashed line indicates a lava flow from 1937

        • I could try something, not much more to add however than what I posted above. Just some basic observation by looking at stuff in Google earth and cross-referencing eruption dates.

      • Wasn’t that larger one pointed in the wrong direction?

        For anyone fiddling with the probability thing, find the likelihood of large events such as this to occur on a daily basis, and then work out how many degrees of travel we make around the sun. Generic probability of getting nailed should be something like;

        P=P(happening) x P(pointed right way).

        If I’m wrong, i’m pretty sure some one smarter will come a long and whack me up the side of the head.

        What I am really trying to get at, is that is is a really small probability… but NON ZERO. (and you know what that means 😀 )

    28. Im very supprised a .. theoretical physcisist like Michio Kaku thats well known and deep into research
      Have started to talk rubbish about Yellowstone
      The dough is indeed very stale inside his volcanic mind.
      Next time I bakes bullar ( Buns ) I will always think of Michio Kaku when making the dough that stale viscous dough thats clouding his volcanic mind.
      Michio Kaku and the stale dough is one of the most funny VC articles so far

      • If he continoues his yellowstone campaign
        He will then be just another dumb Yellowstone – Nibriu Troll … by my opinion

      • I am not sure that is quite fair, as he never said that Yellowstone would erupt like this. He just used it as an example of a large eruption. This was unwise, in my opinion, as this gives fuel to disaster junkies.

          • That’s a three year old interview and he says there’s no current danger in later interviews, Lately he has seemed to shut-up on the subject completely. However his old interviews keep getting referenced and he should have done more research before appearing on tv in the first place.

      • Wouldn’t stale dough almost make something like a cracker? {saltine} Or maybe hardtack?

        I’ve made hardtack using a recipe authorized by the US Army (circa 1850’s). Some really mean stuff to TRY to eat.

        (per the recipe, the finished product should have the consistency of a brick)

        The stuff can cause you to chip a tooth if you eat it wrong. Typically it was used with a bowl of beans to soften it up a bit. My motivation to try and replicate it comes from seeing a diorama of a typical cave dwelling cut out of the loess soil during the 1863 Siege of Vicksburg by
        the residents.

        BTW, if you ever get a chance to tour the battlefield park there, it is fascinating. When I was much much younger, we used to go there to look for ghosts. Never found any, but the area can creep you out when you think about the casualties from the battle.

        Now a bit about a movie. In The Good, The Bad, and The Ugly, midway through the movie Tuco and Blondie wind up at a river crossing/bridge that has a stalemate of Union and Confederates on either side of the river trying to keep the other side from destroying the bridge. (bridgeheads are always important in military operations). The setting for the Union side is almost a perfect example of the fortifications and ramparts that were used at Vicksburg. While the movie is entirely fiction, in my opinion it did an really good job of portraying the conditions of that war. It matches the technology and settings very very well when compared to period era photographs. It also does a good job of portraying the futility and frustration of war in that scene.

        Historical note. In the march to Vicksburg from Jackson MS, the Union Army occasionally removed sections of the rail tracks, heated them, and wrapped them around nearby trees in order to prevent them from being used to repair the rails (should they have failed to take Vicksburg I imagine).

        They also left Jackson completely razed. I think only one building other than the Old Capital predates the war. They used the Old Capital for stables. For a time, Jackson was known as “Chimneyville” since that was all that was left standing.

        A screen cap from another movie that pretty much give you an image of what was going on in Jackson at the time.

        • I’ve worked fires of this nature, one thing I can tell you is that you wouldn’t believe just how hot it is. I’m pretty sure the camera man was using at least a moderate telephoto, because at this range it is almost unbearable without protective equipment.

      • South of Kilauea. The area of this quake had shown a bit of subsidence in the past weeks.

        GOPM, vertical change:

    29. Take a peak at APNT south of the quake on the coast. It has matching movement (vertical ) in December and now, but in the opposite direction?

      • interesting. This one is close to the ocean, so it suggests there was some movement of the crust below the pali, southwards, causing subsidence at one end and inflation at the other. It would make sense if this triggered the quake.

    30. Returnin to the main theme, I find funny that so big drama has not yet the one or two culprit(s) identified.
      In your opinion, this is because no one has yet seriously searched about (I mean expeditions etc) or trhe question is so intrinsecally difficult to answer that maybe we will never obtainany result ?
      Some time ago, in this Cafè another group of volcanoes proposed for the killer eruptions was proposed to be a group of saharian volcanos : aren’t they a possible culprit ?

      • The seriousness of the 536 event was only realized in the past 20-30 years, and there is still a lot of discussion on the correlation between the archaeology and this event. It is also not that easy to identify a particular volcano for a particular eruption. Even the culprit for the massive 1809 event is not known, and the 1257 one (Rinjani) was only identified a couple of years ago. As for Africa, that is always a big uncertainty. We don’t really know what it can do and has done as Carl has pointed out on this blog. But in this case my feeling is that it is mostly too far south, and an eruption in Ethiopia would probably (but not certainly) have been noticed.

      • And Ethiopia had been pretty well occupied since the times of Ancient Egypt… some quite literate and prone to scribbling stuff down, some less so.

        • I am inclined to think that the less so made up the bulk of the population since there is almost no reported eruption before 1900. But however ethiopians have recently started to date ash layers conserved in lakes, one of them (erupted from Corbetti Caldera) is dated close to 536 but it seems to have been just a VEI 5. It doesn’t seem gthe area had eruptions of the size needed around that time.

          • Was it purely explosive or also effusive? I.e, could it have been long-lasting?

            • Publications put it as being purely explosive, there are some recent-looking domes in the area they are mentioned as overlying the tephra, could be a later phase of the eruption or not, I don’t think the domes are large enough to a difference.

              The eruption is dated to be 1.3-1.9 years old and erupted 3 km³ of pumice (and maybe a little more as obsidian domes), doesn’t seem to be big enough, it is also just 7º north.

              There is also Afar more to the north but the Nabro eruption there in 2011 dispersed the SO2 right over Persia, where in 536 the haze doesn’t appear to have shown up.

    31. Great, great article Albert!
      Very surprised that Krakatoa didn’t even crack the list…despite the well documented climate alteration (cooling) that followed…which would indicate a considerable amount of global forcing ensued after the eruption. I wonder if Krakatoa’s cooling effect might have been be more due to particulate injection into the stratosphere, as compared to mere sulfate aerosol formation as with the other volcanoe’s on the list?

      • Stratosphere.

        It takes about 2 Months for the SO2 to fully convert to Sulphate, and about 50 Months to sediment out to pre-injection levels. (stratosphere only, no idea about the troposphere where there is a LOT more moisture) ← I’ve even read papers that look into SO2 scavenging from the eruptive plume in tropical climates vs high latitude climates, I can’t recall the paper… but there is one out there somewhere…

        Caveat: I am not a scientist, just a mudslinger (and I don’t even work with drywall!)

        In other news, my Doctor is an arse. His nurse called my wife to specifically talk to me about my test results, but wouldn’t say anything other than that (HIPPA regulations), then gave her a number for me to call so they can discuss it with me. I call the number… AND NO ONE ANSWERS. I spend the next few minutes freaking out, call central appointments to try and get a hold of some sort of human. I explain my concern, they patch me through to the person I need to talk to, I verify who I am (again, HIPPA regs) and they tell me that I don’t have to bring in the CD from my MRI and the Doc has already reviewed the results. Everything is benign, meaning I’m not scheduled to die from cancer any time soon.

        No, I’m not against HIPPA regulations, they make sense.
        But at least say it’s not bad news so that my wife and I aren’t both freaking out.

        Accolades for following HIPPA but Jeebous! I had a quad espresso and a B-12 this morning so I’m already wired. (The B-12 kicks in in the afternoon so that you can keep going)

        So, after reading the sign at MRI saying they charge $20 for copies of the CD, I burned a copy of he CD iso of my innards to my local hard drive. Feels sort of creepy that a picture of my literal guts are on my hard drive. Is it copyright infringement if it’s a copy of me? After all, I am the only actor on that iso image. Does the MRI tech get a royalty since they were the photographer? It’s my likeness.. well, the likeness of part of me. I signed away a lot of stuff yesterday but nothing said anything about copyright. Doc said I can toss it but I don’t want the dog digging through my trash to get a look at the menu…

        • You might be the first person in history to be sued for copyright infringement by their own intestines!
          More seriously, glad the results are still clear. All the best!

        • Thank you Lurk!
          We here in California have been experiencing a very unusual/anomalously cool Winter, probably associated with the SSW/split polar vortex pattern that pretty much dominated NH weather patterns since late December.
          February was the first month in over 8 years that we had below-normal monthly average temp, which also included a 10″ snowfall at my place in the far northern Sacramento valley….which by all accounts was the largest single snowfall total ever recorded (although Redding further north had a 17″ snowfall back in 1989, but we got zip at my place).
          To highlight the rarity, ~75% of our native Oaks sustained moderate to major damage to limbs and in some cases entire trees coming down from the weight of the snow…which in turn killed all the power for much of the north-state including phone, cell, internet and cable services. As a result, we had almost 2 days without power and cut off from the outside world, half a foot of snow on the ground, and frankly shivering our cumulative “arses” off trying to stay warm…just not prepared for such an extreme event, fer sure.
          While I realize there is little in the way of any definitive data, but one must wonder if Agung may have had a small hand in all of this? All Fall and Winter we’d been noticing a much higher number of brilliant sunsets than usual, which in the past seemed to correlate with opacity changes in the upper layers, such as I saw after Pinatubo and to a lesser extent El Chacon?

      • Krakatoa had no eruption at the time of 536. That was a bit of a killer for the hypothesis it was responsible. The 19th century eruption was large enough to give some climate effect, but it was not large enough to feature in the rankings. Eruptions this size happen about once a century, while the big ones are perhaps once every 300 years. The amount of sulphur in the ejecta also varies, but overall Krakatoa was just a bit too small. Seems amazing for such a famous eruption. That is the other problem with the Krakatoa-for-536 hypothesis: had it erupted, it would have been too small.

        An eruption this size could play a role in a double event, though.

        • Small question for all . So when a plume comes against a craton ( in this case the Greenland Craton) . Is it a case where the plume just goes under it, or something else?. Maybe be like a temporary plug until it passes over.

          • Well, that’s IF the Icelandic hotspot every went under Greenland. There is a body of thought that thinks otherwise.

            As for not punching through and erupting, if a plume did take this track, it might just “underplate” the craton as it passed overhead.

            (Some discussion seen over at IMO have talked of the Icelandic plume as being in an “incipient” stage.)

            • i am sceptical about the hot spot track. It ignore the equally ‘hot’ region in south Greenland. And there is an alternative. This was the last are where America and Europe split up and there were several failed attempts, one of which split Greenland from Canada. Even in the North Atlantic, the rift has jumped, leaving an extinct rift behind. Perhaps there was another attempt at a rift running through Greenland which failed. The actual split, with its outpouring of basalt, happened not far from there.

            • Very interesting. Perhaps a full post on this from someone initiated in that discussion?

          • The Greenland Craton has some of the oldest, if not the oldest rocks on the planet. It’s not unreasonable to assume that the crustal thickness would have been more than high enough to prevent the Icelandic plume from generating much in the way of extensive volcanism, if at all, until just after the KT mass extinction.

            Yet, it’s possible that within the last 20-30 million years before Greenland started icing up about 3-7 million years ago, there could have been maybe some very limited volcanism being generated by the tail of the Icelandic plume a la Yellowstone (with the Snake River postcaldera volcanism in southern Idaho trailing Yellowstone Caldera of course), with any evidence hidden/eroded by today’s ice. Or even limited subglacial volcanism after the ice sheets formed during the Pleistocene, but unlike present-day West Antarctica, never intense enough to penetrate above the ice cap. This is just a little theory I just dished up, but still, I am not a true expert in such matters, nor do I claim to be one.

            • The North Atlantic Igenous province superplume have long since died away

              The smaller Iceland Plume came into life after that
              Otherwise woud emerge at the surface much more early than 10 million years ago.
              Icelands output have also increased over time

            • And isn’t the geology of Greenland similar to the northern half of Scotland? The heat below the surface, with its fingers reaching out in several directions, which we recently discussed, possibly links back to the last major sliding of the surface plates

    32. Found a kml INSAR file for kilauea that was taken between April 20 and May 14 2018, showing the initiation of the 2018 eruption. It is immediately very obvious that the summit deflated, but the actual deflation at this early point was more to the west of the center of the visible caldera, and goes quite far to the south of it too. Pu’u o’o obviously has a blue patch, but the bit that caught my eye was that under heiheiahulu there is an equally blue patch, just north of it and almost directly under JOKA station. it appears there is a magma body here after all. Looking at this too, it is probably not coincidental that fissure 8 was both the biggest of the early fissures, and the one that the eruption eventually settled at almost a month later, it is right in the middle of the red.

      I dont really know what is happening on the south flank regarding the big May 4 earthquake, I think the red is both up and east so maybe that part moved east more than down, same for the tip of the rift zone that is probably from being very slightly pulled west as the area just uprift inflated though all that is just a hypothesis.

      Important is the clear lack of any deflation uprift from makaopuhi crater at all, at mauna ulu there is basically nothing and yet both the summit and middle rift have fallen heavily, this pretty much confirms there is no very shallow magma pathway in this area, the middle rift is probably fed at a deep level starting at mauna ulu and the rifting at koae is a temporary solution to this gap, with either the east rift moving north or kilaueas central volcano going south into the faults. The original east rift actually was further north so the latter seems more likely.

    33. Image from Mars, published by ESA

      This is not an alien spider. It is Mars’ equivalent of tornado alley, a location which attracts monster dust devils. The white colour is photoshopped: it is probably the usual Martian red.

      • The dark arera sucks up sunlight and becomes hotter
        That starts the dust devils

      • Caution… you are getting into an electromagnetic theory espoused by a Signalman I used to know. His belief was that my passive antennas were dangerous since they “sucked in” all that RF energy.

        Part of the equipment that I used has active elements for transmitting deception signals. Yes, those are dangerous to hang-out near when in operation, but the area is well marked and cordoned off so you can’t get out there and stand anywhere near the beam… which in this case, you would have to hover over the side of the ship to get into it. (meaning you would likely be swimming before you suffered any harm.) Nothing really wrong with his caution, He was just a bit too freaked out by the warning placards. (and prone to over-embellishment by his coworkers who giggled quite profusely when jacking up his paranoia)

        Dark colors do not “attract” energy. They just reflect less of it.

    34. Sicily has had some very large eruptions in the past. The eruption of 396 BC was recorded by Diodorus of Sicily.

      Diodorus Siculus. The Library of History. Vol. 6
      [Diod. 14.59.3. Translated by C. H. Oldfather. Harvard University Press. 1935. (12 Vols.) p. 175]

      Himilcon, advancing with his land forces, made so rapid a march that he arrived at the same time as Magon put in there by sea. But since there had recently been a fiery eruption from Mt. Aetna as far as the sea, it was no longer possible for the land forces to advance in the company of the ships as they sailed beside them; for the regions along the sea were laid waste by the lava, as it is called, so that the land army had to take its way around the peak of Aetna.

      He also noted a much earlier large eruption

      “The Sicani, then, originally made their homes in villages, building their settlements upon the strongest hills because of the pirates; for they had not yet been brought under the single rule of a king, but in each settlement there was one man who was lord. And at first they made their home in every part of the island and secured their food by tilling the land; but at a later time, when Aetna sent up volcanic eruptions in an increasing number of places and a great torrent of lava was poured forth over the land, it came to pass that a great stretch of the country was ruined. And since the fire kept consuming a large area of the land during an increasing number of years, in fear they left the eastern parts of Sicily and removed to the western. And last of all, many generations later, the people of the Siceli crossed over in a body from Italy into Sicily and made their home in the land which had been abandoned by the Sicani.

      • That is fascinating history. Looking at a map, the area overrun may be the coastal strip north of Catania. Bad news for everyone who lives there – and it is quite densely populated. As to where the people living there could have gone, there is a bay on the southwest side (around Gela) which would have been similar for cultivation. It would have left the coastal strip empty.

    35. Long ago Etna did a 10km3 basaltic plinian event that dropped ash on rome even I think
      That event formed its now almost completely buried and filled up summit caldera thats just barely visible its edges. Think grimsvötn 2011 but 10 times larger or larger and without Ice.
      That event showered the whole catania arera with black ash and lapilli
      Masaya done even larger Basaltic Plinian eruptions before
      Basaltic Plinian eruptions are rare. Basaltsa are quite fluid to very fluid and often allows gases to escape
      Only the most gas rich basaltic magmas does these stuff

    36. New swarm under Langjökull. I’ll bet Irpsit will find it interesting 😉

    37. Langjökull wont do anything not a frequent erupter
      But when it well happens it can get very large.
      Some slow pahoehoe in that system produced 50 km of lava at once and lasted for decades

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