Two pillars sit at the end of the world. To the ancients, the entrance to the Mediterranean Sea was the end of the known (civilized) world. Mythology tells us that Hercules smashed the mountains to create an opening, flanked by two pillars. We don’t quite know which mountain was the southern pillar, but the northern one remains famous: the Rock of Gibraltar, still overlooking the ancient opening. It has a story to tell.
It looks out at the sea that keeps humanity apart. The very name means ‘Sea that divides the land’. The Mediterranean Sea forms a deep division between Southern Europe and North Africa. It wasn’t always: once this was a region with a common culture, tied together by the sea farers and their trading, in a Mediterranean melting pot of peoples and cultures. The sea has islands, volcanoes, high mountains and major rivers (well – two, to be precise, the Rhone and the Nile.) The deepest point is more than 5 km below the surface. And it has deep history. It binds west to east, north to south, and gave us the names of the The West and The East. It is so much more than a division. This sea has everything.
The most common name used by people living along it was ‘The Great Sea’ or just ‘The Sea’ as it is called in the bible. The Romans called it ‘The Internal Sea’, an appropriate expression as their empire covered the entire coast, north and south. Before that, in the heyday of ancient Middle Eastern cultures, this was the Western Sea (also known as the Syrian Sea). At a time when colours were used to designate directions, it was known as the ‘White Sea’ where white stood for west. (Black was north and red was south, explaining the names of the Black Sea and the Red Sea.)
The Mediterranean Sea is 4000 km long, equivalent to the entire breadth of the USA. One may wonder why it isn’t considered an ocean! The width varies from 2000 km north of Libya to 14 km at the Strait of Gibraltar. Some parts have their own names. There are 14 seas included in the Mediterranean Sea, such as the Aegean Sea. (The Sea of Marmara is sometimes included as number 15.) The number of islands is uncounted, but is at least 6000. The coast line and sea are shared among 24 countries and autonomous regions (including Palestine and Northern Cyprus), a long cry from the days of the Roman Empire. More than 150 million people live along its coasts. The world comes together around the sea that keeps them apart.
But amazingly, this enormity has only three narrow entrances. One of these has already been mentioned: the Strait of Gibraltar. The Dardanelles is even narrower, at 1.2 kilometers. And the third one is the narrowest of all and had to be dug by hand: the Suez canal. This sea of division is itself rather isolated. In consequence, it has very limited tides. The limited inflow from rivers adds to the difficulty this sea has. The Mediterranean Sea loses water to evaporation across the entire surface, amounting to around 0.5 meter per year. This is replenished through precipitation, river inflow, and flow through the Straits of Gibraltar in the far west. It takes a while before this circulation reaches the easternmost part where evaporation is highest. Because of this delay, the water level in the east is lower than in the west. Salinity at the surface is also a bit higher in the east. Replenishing the entire sea with Atlantic water would take a century.
Structure
The Mediterranean Sea is a complex jumble of ridges, plateaus and basins. There are continental shelfs along the coasts, in most places relatively narrow but larger along Tunisia and in the Adriatic and the Aegean seas. The plateaus are mainly found between Italy and Libya. Sicily and Malta share such a plateau, as do Corsica and Sardinia. There is a large, deep basin in the west, stretching from Gibraltar to west of Corsica. A second deep basin extends from east of Malta to Lebanon but it is broken up by many ridges and partly filled in by sediment from the Nile. A deep trough bends around Greece and Crete towards Turkey. Another trough runs within the Aegean Sea, an extension of the Turkey North Anatolian fault.
The structure gives rise to two main parts, the western and the eastern part, separated by a shallower rise connecting Italy to Africa. Thus, the Mediterranean Sea is a double sea, separated by a ridge. Compared to the simplicity of the Black Sea, this is a broken sea.
Volcanoes
Source: https://blog.navily.com/en/blog/the-mediterranean-volcanoes/
There are well-known volcanoes along and within the Mediterranean Sea. Italy has Etna, Vesuvius (where Pliny the Elder started the science of volcanology), but also Vulcano (whoever thought of that name?) and Stromboli. Greece has Santorini. But there are more. The ones we know well are just the ones that get their head above water.
An interactive map of the submarine activity can be found at https://maritime-forum.ec.europa.eu/contents/map-week-submarine-volcanoes_en. The hotbed of under-water volcanic activity is in the Tyrrhenian sea, between Italy, Sicily and Sardinia. The sea bed here is littered with domes, cones and mounts. There is a second field southwest of Sicily. A third field lies south of Spain but this is no longer active.
The Tyrrhenian Sea is home to Vulcano and Stromboli, both close to the coast of Sicily. There are many more below the water. Some, like Palinuro, nearly reach the surface. Palinuro contains some 15 separate cones. It may have formed short-lived islands during eruptions and would have been above water during the ice age. A tephra layer found in Italy has been attributed to an eruption of Palinuro 10,000 years ago. Marsili lies deeper but is larger: this volcano is considered larger than Etna. The mount is younger than Palinuro but it is not known whether it remains active.
Volcanic activity in the Tyrrhenian Sea appears to have migrated south over time. It is currently focussed mainly on the islands some 50 km of the north coast of Sicily. This group known as the Aeolian islands (including Stromboli and Vulcano) forms a small island arc: all seven are volcanic but only two are active.
The second volcanic field lies between Sicily and Tunisia. It is known as the Campi Flegrei del Mar di Sicilia (a descriptive name if ever there was one) and contains one larger permanent island, Pantelleria, and a smaller one, Linosa. Both are volcanic. (Lampedusa, nearby but close to Africa, is not volcanic.)
Pantelleria’s most recent eruption was in 1891. The event started in May/June 1890 with earthquake activity and uplift. After taking a year out, this was followed in October 1891 by much stronger seismic activity lasting 10 days, before an eruption started off the northwest coast. The eruption barely broke the water surface but it resulted in a phenomenon called ‘lava balloons’: meter-long, floating lava bombs. The eruption lasted for a week; the large size of the ‘lava balloons’ suggests that eruption rates were high. The eruption site was finally found ten years ago, as a young cone, 90 meter tall and reaching to 250 meters below the surface. The cone is located within a large volcanic field with many other cones, part of the Pantelleria rift.
Closer to Sicily are several other submerged volcanoes. The most curious of these is the so-called Nameless Bank (possibly the most google-proof name of any volcano!). There is also the small Terrible Bank and the much larger Adventure Bank. All three Banks are volcanically active. The last one is is also known as Empledocus, and is a large volcano with multiple eruption centres of which Ferdinandea is the most active. This vent has broken the surface several times since Roman history. The last time was in 1831 when it caused a major political row. In fact, this row still echoes on in the naming: Ferdinandea is also known as the Graham Volcanic Field. In 1831, an eruption here formed a new island. It is mentioned in a post on a mysterious island. The 1831 eruption appears to have been much larger than realized at the time. It led to the Sun taking on strange and unusual colours in various, distant locations. The island was quickly claimed by Sicily, France, Spain and England, and thereby acquired four different names. It was all in vain as the island disappeared again within 6 months. It still remains 7 meters below sea level – enough to create a shipping hazard. (It also very briefly re-appeared in 1863.) To avoid any recurrence of the territorial un-integrity, Italy has pre-emptively claimed the ephemeral island by dropping a water-proof flag and marble plaque. Neither survived long.
There is an another volcanic island arc in far east of the Mediterranean Sea, located in the Aegean Sea. This arc is much better known as it includes famous Santorini.
There is a bit of a pattern: the volcanoes avoid the deep western and eastern basins. They are active in the shallow regions of Aegean Sea and the Sicily Straits, and in the small Tyrrhenian basin. Each of the three region has a different causes of the volcanism, but these are clearly the geologically active areas.
Faults
Geology is a science looking for faults. And the Mediterranean Sea is full of faults. The map of the various fault lines looks psychedelic even in black and white.
The pattern of faults shows how complex the region is. Amazingly, apart from the westernmost region, Africa is free of faults. But the sea and the land to the north (Europe) are full of them. In simplified maps, there is often a single plate boundary drawn between Africa and Europe, bisecting the Mediterranean. The real situation is far more complex.
In the west, a fault surrounds much of the western basin, running through southeastern Spain and North Africa towards Sicily where it peters out. A second fault runs through the Atlas mountains also to Sicily, but passing south of the island and bends north into Italy and the Adriatic Sea.
In the east, several fault lines run along either coast, and there are fault lines in Turkey. Finally, the Mediterranean basin terminates at the Dead Sea fault.
Children of the Tethys
In the beginning was the Tethys.
(This is not entirely true, there was actually quite a lot that went on before it. But much of the structure of Europe and south Asia was caused by the dance of the plates of the Tethys ocean.)
There were several Tethys oceans, as far as oceanic plates are concerned. The ocean first began to form where China is now, like a slow Allemand at the start of the baroque dance movements. At the time, the continents were merged into a super continent, but this began to rupture in the east. It started as a large bay and grew to become an ocean. The southern part of the supercontinent moved away to become Gondwana while the ocean grew between it and the north. The Tethys ocean expanded westward. (Strictly speaking this was the Paleotethys, the ocean before what we normally call the Tethys ocean.) It finally reached the newly formed Atlantic ocean. But now it was becoming squeezed again as the south was on the move back. Oceans do not last forever: ocean crust eventually subducts, and the ocean plate moves towards its oblivion at the subduction zone. In the case of the Tethys ocean, the subduction zones were all at its northern margins, and the subduction pulled Gondwana back in. The world sped up in the Courante, the next phase of dance.
The Courante did not go smoothly. Rifting within the Gondwana continent would send parts of it north, to collide with Asia (and later Europe). The rift would create new ocean floor behind the continental fragment. So, the Paleothetys was superseded by the Tethys and later by the Neotethys. They all suffered the same fate, while in the process Asia and Europe acquired new land to the south while Gondwana became smaller.
Much of southern Asia and southern Europe are accreted parts – the remnants of the original Tethys ocean lie here. The Himalayas and the Alps show where some of the fragments docked. Each time an ocean was lost; and each time it reformed and was lost again.
After 70 million years ago, the Tethys began to close for good. An era drew to its close as the slow dance of the Sarabande played in the seas. But the ocean survived in the west, albeit with a fragmented oceanic plate. This became the proto-Mediterranean Sea. 20 million years ago it lost its connection with the east, overridden by the northward movement of Arabia. This left the proto-Mediterranean isolated and without a through-flow. Perhaps this situation will not last forever: the newly formed Red Sea, another re-incarnation of the Tethys ocean, may eventually reconnect to the Mediterranean and open it up to the Indian Ocean. However, so far has the Red Sea has fallen short.
The psychedelic tectonic map of the Mediterranean is a relic from its complicated history. Different parts have evolved differently. Continental fragments have jumped across, in a variety of places. In the west, the Balearic basin is surrounded by thrust faults. Further east, there are several subduction zones, starting with the Ionian Sea which is subducting towards Sicily. This is probably the cause of the volcanism in the Tyrrhenian Sea. Subduction around the Aegean Sea explains the volcanism there. The volcanism south of Sicily has yet another cause. This occurs on submerged continental crust (the ridge dissecting the Mediterranean). A graben or rift which runs parallel to the African coast indicates extension is on-going: the volcanism occurs on the thinned crust. Perhaps there will be future rifting, a young ocean crust will re-form and the eastern and western Mediterranean will reconnect.
In the far east of the Mediterranean, there is growing instability from the Turkish plate. It is moving fast towards the west, caused by Arabia moving north. The stress here is a consequence of the closure of the east-west oceanic connection in our post-Tethys word. The North Anatolian transform fault, accommodating this movement, is currently extending into the Aegean Sea, and moving towards the Greek main land.
This is the final dance, the Gigue, where everything quickens before coming together.
The Mediterranean Sea is a conflicted zone. North and south, east and west (black and red, blue and white) meet here, in a dance that has been going for hundreds of millions of years. Is this the end, the final movement? Africa continues to move north, albeit at snail’s pace of less than 1 cm per year. Eventually this should close the Mediterranean Sea and bring to a close the era of the Tethys: ‘Ruhe Sanfte; Sanfte Ruh’.
Plate movements relative to Europe. Source: Miramontes et al., 2023, Oceanography of the Mediterranean Sea, Chapter 2
But it may not. The Tethys has managed to avoid this fate before. It does so by rifting at its southern edge, creating a new ocean crust. Will this happen again? The only sign of any rifting is south of Sicily and it is very minor. Could it grow? Perhaps more likely, could the Red Sea finally get its act together and grow west, into the Mediterranean?
Crisis in the Med
Conflicts bring crises. The Mediterranean Sea has seen many wars around its shores. Even the Pax Romana did not bring lasting peace. But its biggest crisis did not come from humanity. It came from the Earth itself.
There is a fragility in the Mediterranean Sea. The lack of through-flow causes dangers. It has happened elsewhere in the Tethys, when parts of it became isolated and stagnant, but nowhere as serious as in the Mediterranean Sea.
The Strait of Gibraltar is crucial to the survival of the Mediterranean Sea. The water that flows through from the Atlantic Ocean keeps the sea alive: without it, the water level would begin to drop. There is also some inflow through the Bosporus and Dardanelles, channeling the water supply of the major rivers entering the Black Sea: the Danube, the Dniepr, the Don.
The flows go both ways. The inflow from the rivers and the Black Sea amounts to around 11,000 m3/s, the large majority from the Black Sea. The inflow from the Atlantic Ocean through the Strait of Gibraltar is around 600,000 m3/s. There is also an outflow through the Strait of Gibraltar which is nearly as much. The net inflow balances the evaporation rate which averages to 40,000 m3/s. But salt does not evaporate, and therefore the outflow must be a bit saltier than the inflow so that the Mediterranean Sea does not get any saltier.
The Mediterranean Sea is indeed saltier than the Atlantic ocean, and a lot saltier than the Black Sea. Saltier water is heavier. The inflowing water is lighter and therefore flows at the surface. On return, the saltier water flows along the bottom, through both the Strait of Gibraltar and the Bosporus. The inflow and outflow can happen simultaneously, one above and one below. It is give and take. But more water flows in than out, to compensate for the evaporation in especially the eastern Mediterranean Sea.
The Strait of Gibraltar contains a barrier around 25 km west of the narrowest part of the Strait, where the depth is as little as 100 meters. This is called the Camarinal Sill. Elsewhere it is deeper. There is a channel that is up to 300 meters deep and ends in the Gibraltar Trough, a 600-meter deep feature that connects to the Gibraltar or Alboran Basin, reaching 960 meters. The inflow and outflow pass through this channel.
Isolation
Image source Duggen et al. 2003, Nature, 422, 602
The crisis started in Spain. Around 7 million years ago, the region began to experience uplift. At this time, the Mediterranean Sea was connected to the Atlantic Ocean via two corridors, one north of the current Strait and one south. The southern one (the Rifian corridor) ran along the current Atlas mountain; it was the deeper of the two at some 700 meters. The northern channel (the Betic corridor) ran from south of Seville to Valencia. The Strait of Gibraltar did not yet exist: between the two channels was land. Whether there was also a direct connection to the Black Sea (or the Paratethys, at that time) is not known.
The uplift coincided with volcanic activity stretching across 500 km from southeast Spain to North Africa. This was not caused by a mantle plume: the volcanism was triggered by upwelling from the asthenosphere, the layer between crust and mantle. The precise cause is still under discussion. One suggestion is that the subduction of the old Tethys oceanic crust was rolling back westward, and that the upwelling filled in the hole. As the new material was much warmer than the cold oceanic lithosphere it replaced, the land was pushed up.
The evidence for the uplift can still be seen in fossil reefs in the region along the two channels, which are several hundred meters above sea level. As the land rose, the two channels narrowed. The Betic corridor may have closed as early as 6.3 million years ago. The Rifian corridor ceased to exist by 6 million years ago. A surprising consequence of this came 6.1 million years ago, when camels briefly appeared in Spain. Exactly how and when they crossed the remaining water barrier is not clear.
Water went in and out through the channels. But as the channels became shallower the return flow became impeded. Salt went in but not as much was able to come out. The Mediterranean Sea became saltier.
There had been signs of trouble for some time. Between 6.3 and 5.97 million years ago, plankton became gradually less diverse. This was probably caused by increasing salt levels. It is possible this can been traced back even to 7 million years ago. The outflow has gradually become more restricted.
Water can dissolve a limited amount of salt, before the salt begins to come out of solution. The crisis point was reached 5.97 million years ago, when suddenly, across the entire Mediterranean Sea, deposits of salts and gypsum began to appear. It seems likely there was a worsening of the situation at this time, perhaps with the outflow being further reduced. This would continue for the next 380,000 years. The gypsum and salt layers were not deposited at a constant rate. It was cyclical, with slowly increasing salt levels followed by a return to lower levels, and again a slow increase. There are 16 of these cycles visible in the deposits.
The saltiness (salinity) stabilized further during this time. It reached as high as 15% but did not go further, at least at this time. Gypsum formed, but halite, which forms under higher salinity, did not. There was still some regulation of salt levels, with the deposited salt and lost water being continuously replaced by the inflow from the Atlantic ocean.
There is a bit of a conundrum here. The stabilization of the Mediterranean Sea, albeit at a higher salinity, shows that it still continued to receive water from the Atlantic Ocean, and there must even have been some outflow of excess salt. But both channels had already closed, as far as we know. Models show there must have been a remaining shallow channel several kilometers wide, otherwise the salinity would have gone much higher. Which channel was this? (And would this not have kept out the camels? Perhaps the volcanic eruptions briefly closed the channel at times, with camels taking advantage of the opportunity. Speculation.)
It has been suggested that the inflow at this time came from the Paratethys or Black Sea. However, this could have replenished the water but not the salt as the Paratethys was only brackish. There must have been an unrecognized connection to the Atlantic Ocean.
The solution may be the obvious one. With the two main channels closed, the Gibraltar channel may already have existed and provided the missing link. It is really the only realistic candidate that we know about!
Gypsum was deposited mainly where the water was less than 200 meters deep. This suggests that the water was stratified, as is common in hyper-saline water bodies. At lower depth, the oxygen levels may have been depleted. The Mediterranean Sea was not a happy buddy.
Desiccation
This troublesome phase ended 5.59 million years ago, but not for the better. The second phase of the crisis began. At this time the remaining connection to the Atlantic Ocean was lost, whether this was at Gibraltar or elsewhere. Whether it was blocked completely or just severely restricted is a moot point: any inflow was no longer sufficient to keep up with evaporation. This may have happened intermittently before, but so far it had always re-established itself. Not so this time.
Little new ocean water came into the Mediterranean Sea. Rivers still brought in fresh water and rain would fall, but this could not keep up with the evaporation. Sea level began to drop at some 50cm per year. (Incidentally, this is similar to the rate as seen in the Aral Sea.) Within 1000 years, the sea would have been down by a staggering 500 meters, the surface level of the modern Dead Sea. All around the basin, the coast line receded. Rivers eroded deep canyons into the newly dry land. Any chance of a salt-water flow back towards the Atlantic ocean was gone: water does not voluntarily flow up-hill.
The precise cause of the blockage is not known. Worldwide, the cooling towards the coming ice ages had begun. As glaciers grew and declined, sea level fluctuated by as much as 50 meters. Part of the blockage may just have been from this. But the fact that it lasted so long suggests that there had also been a more lasting change in the remaining channel. One possibility is that the salt deposition was having an effect. It is similar to having an ice-age glacier lying on the land: the weight would have depressed the surface below, and thereby lifted up regions further out. Perhaps this isostatic uplift was the ultimate cause. Or perhaps an inconvenient volcano was to blame!
As the sea became saltier, new gypsum layers were deposited. Previous layers were now above water and became affected by erosion. Slopes became unstable and there would have been many landslides. These deposits are called the Resedimented Lower Gypsum (RLG) and they can provide a chaotic picture. The picture below shows such a deposit, found on Sicily. Earthquakes and tectonic activity became widespread at this time.
Source: Roveri et al., 2008, Marine Geology, 352, 25
And it did not stop there. The desiccation continued for 50,000 years. How far sea levels fell is not known. Some argue it did not fall much below 500 meters. Others find it could have fallen by as much as 1.5 or even 2 kilometers. In that case, only the deepest basins remained – everywhere else the sea became dry. Moses would have had no problem escaping from Egypt, although the journey across the salt-covered desert would not have been pleasant, or survivable. A recent paper argues for both, claiming that eastern Mediterranean went down by 2 km but the western basin only by 800 meters – the Sicilian barrier divides these basins, so they can evolve separately, depending on what inflow they could still get.
Two different views of the Mediterranean during the worst epoch of the crisis. Source: Krijgsman et al. 2018, Marine Geology, 403, 238
This was the heart of the Messinian Salinity Crisis. It is called that, by the way, after the geological epoch, which is named after the city on Sicily where Messinian salt and gypsum deposits are found – whether that means that the salt is named after the epoch or the epoch after the salt is an open question. The name was assigned to the epoch long before the Mediterranean crisis became known.
Halite began to be deposited, eventually reaching a staggering thickness of 2 kilometer in places. Halite forms in water with salinity of at least 35%: this extreme saltiness lasted for some 50,000 years. After that the Mediterranean Sea was unrecognizable. An arid phase followed with little rain: there no longer was a large body of water to provide a source of rain! The temperatures in the exposed regions would have been high. For every 120 meters of elevation, temperatures change by about 1C. At 500 meter depth, where the shoreline may have been for a while, it would have been 5C hotter than before. We can see all around us what just 1.5C of warming does. 5 degrees would have turned the place into an inhospitable desert. And the sea level even may have been as much 1 kilometer lower than this, tripling the heat. The surrounding regions would have been affected by the drought, the sand storms and the blowing salt. Times were not good.
This type of event has happened elsewhere. In fact we are ourselves have caused just such an event, though at a very much smaller scale, in another relic of the Tethys: the Aral Sea. But the Messinian crisis was off the scale. Over 400,000 years, over a million cubic kilometers of salt, 5% of all the salt dissolved in the world oceans, was deposited on the sea floor of the Mediterranean.
Lago Mare
The third phase of the crisis began when a ray of hope appeared 5.55 million years ago. The salt level of the remaining water reduced to below 35% – halite formation ceased. Fossil remains of fresh-water fauna have been found, suggesting the presence of lakes on the dry sea floor. Clearly, a new source of water had appeared. The most likely origin is the part of the Tethys ocean that covered the area around the Caspian Sea, the Paratethys. It may have started to overflow into the dry Mediterranean basin. This is the time of the ‘Lago Mare’, the lake-sea. The evidence is not fully consistent. Other studies find evidence for marine fish, which could only have come from an Atlantic overflow.
Overall, the indications are that conditions moderated. The climate became more humid. The water level stabilized, may even have gone up a bit, or may have fluctuated wildly – all have been suggested.
The Mediterranean Sea had gone through a deep crisis. But the worst seemed to be over. There were stirrings of life again. The three phases were like Bach’s famous Chaconne, the most emotional of his dances.
The mystery channel
There are major questions about the era of the Lago-Mare. How low did sea level go? (It may have been different for different basins.) What was the role of the Paratethys? And most of all, where was that mysterious channel to the Atlantic Ocean?
The depiction above is from Krijgsman et al 2018, Marine Geology, 403, 238. They have looked in detail at the various channels from the Atlantic Ocean. The Gibraltar region was a complicated one, with a variety of possible pathways for the water. But they find that most of those had closed long before the events. In the depiction, green indicates when the channel became dry land. Black means no data – erosion may have wiped out the layers of that age. The indications are that all channels had gone by 6.5 million years ago, with the possible exception of the north Rifian channel where no data has been found. After 5.3 million years ago, the modern Gibraltar channel is established. Before that, there is a lack of data on it. There is a good case that the mystery was indeed hiding in the open: Gibraltar.
The sea floor in the region shows an incision which runs for 300 km or more to the east, with a downward incline. It begins 20 km west of Tanger, well into the Atlantic ocean. The incision is filled with as much as 300 meter of sediment but remains identifiable. In the Strait, it splits into two branches, leaving the Camarinal Sill in between. The incision is around 2 km wide in the north arm and 4 km in the south arm. That is pretty much the size needed for the inflow during the early phase of the Messinian Salinity Crisis, and deep enough to provide for some outflow. Thus, it seems plausible that this is the original channel that remained active between 5.97 and 5.59 million years ago.
If so, the likely cause of the second phase of the Messinian Salinity Crisis is that the Strait of Gibraltar became blocked, and the third phase was help by a partial re-opening – perhaps just a bit of an overflow.
The Zanclean flood
The end of the crisis was spectacular. It happened 5.33 million years ago when the barrier at Gibraltar broke down and the time of the Lago Mare came to an abrupt end. It is called the Zanclean flood, after the geological epoch of that name. It is also the official starting gun for the Pliocene.
Geologically speaking, the change was instantaneous. There is no transition layer. Plankton re-established itself: the Mediterranean was a normal sea again with normal salinity. But in the deeper basins such as the Tyrrhenian, the recovery took much longer, perhaps 50,000 years. Even though the upper levels were normal, the deeper levels remained very salty, dense, and slow to mix with the healthier upper levels. This may have taken 50,000 years.
There is no mystery about the location of the new channel. The Strait of Gibraltar existed after this time, and it is the only candidate. But how fast was it? And what caused it?
One model is that of a sudden collapse of the Gibraltar barrier. If that were to happen with sea level in the Mediterranean basin 500-1000 meters lower, the event would have been catastrophic. The cascade would have quickly deepened its channel, allowing extreme flow rates. The whole sea would have re-filled within two years, with water level rising at 1 meter per day. This is called the Zanclean flood. This would fit with the 390-km long channel scoured into the Gibraltar Strait all the way to the Alboran basin, and to the 960-meter depth of this basin. This is the image that made the crisis so popular. Noah had nothing on this. A kilometer-tall waterfall with a flow rate of many times that of the Amazon river, who could resist?
But there are other models. One model suggest that there had been earlier inflows, and that the Mediterranean basin had already mostly re-filled, but step-wise. Another one suggest water levels were only a few hundred meters below that of the Atlantic ocean, requiring a far less dramatic flood.
The major uncertainty is in what the Mediterranean Sea looked like between 5.55 and 5.33 million years ago. Was it dessicated, with water limited to deep basing and lakes fed by individual rivers? Was it nearly full, with water only a few hundred meters below base level? Or was it fluctuating between these two, as some have suggested? The second option does not require a catastrophic flood event. We don’t know. The picture of the Zanclean flood is irresistible, too good not to be true.
The solution may be hiding around Sicily. In the second model, the Mediterranean is a connected basin, an ocean with islands. But in the first model, with water levels 1 kilometer below (or more), the sea is divided into separate basins, where the area around Sicily provides a barrier which separates the two halves of the sea. The western half would fill first in the flood, and then overflow into the deep eastern basin. That overflow should have left scars. Indeed, a deep, chaotic layer of sediment has been found here, but it is not accurately dated. So the Zanclean flood remains a mystery – or should that be a myth? Is it too good to be true?
Even in the mildest model, this was a spectacular mega-flood. Think 10 to 100 Amazon Rivers thundering through a corridor a few kilometers wide and cascading down 500 meters, lasting for years. The initial flow rate may have been as high as 0.1 km3 per second, flowing at speeds of 100 km/hr. Once the barrier broke down, erosion would have a field day.
What caused the reflooding? The cause is clearly in the Atlantic ocean. The global sea level may have risen higher than before, as the climate warmed a bit, leading to an overtopping of the Gibraltar block. Or the land may have become lower, either due to a tectonic adjustment or due to erosion. In either case, it would have been a long time in the making. The pressure of a sea that is a kilometer higher on one side of a barrier than on the other side is immense. If the land barrier weakened, for instance from a large earthquake or landslide, it could have failed catastrophically. A slow overtopping might have done something similar, causing a large waterfall on the far side which slowly eroded its way back – until the land could no longer withstand the water. Hercules saved our world.
After the end
In the beginning was the Tethys. Our world has been shaped by the Tethys ocean. It is an ocean that lasted for hundreds of millions of years, disappearing only recently. The Tethys has left signs of its past existence everywhere, from the basins of the Black Sea and Caspian Sea to the long mountain chains stretching from Spain to Myanmar. The Tethys ocean reformed parts of it many times. The Mediterranean Sea is one of those reformations. Perhaps it is not the last one: if the Red Sea eventually were to form an ocean it would have a claim to be the latest incarnation of the Tethys.
The extreme events that the Mediterranean Sea experienced 5.5 million years ago may have occurred elsewhere during the closing of the Tethys. Africa is by far the largest fragment that closed the Tethys, but did smaller fragments do similar things on a smaller scale? And continents have collided before, leaving us their ancient mountains chains. Did similar events to the desiccation of the Mediterranean Sea occur at those times? Plate tectonics can be a frightening dance. Humanity is not foremost in its mind.
Still, the earliest hominids were around when these events played out. Did they see the desiccated sea? Was Hercules one of them? We know not, but it is an interesting thought. Out of Africa – into the abyss.
The Rock of Gibraltar is still there. It is made from limestone that is far older than the Mediterranean Sea, but it is looking at a seascape that dates to the heady days of the Messinian Salinity Crisis. Here is the gateway that saved an ocean. It saved our divided world.
Albert, 25 December 2024
A more recent flood is described in Jokulhlaup in the English Channel
A bit of Mediterranean history can be found in And the sea was no more: the story of the Tethys marbles
From All of Us to All of You: Happy Christmas!
Optical Illusions
For Christmas entertainment, here are some images
Which colours do the balls have? Believe it or not, they are all the same colour.
A Christmas star: rays of light are seen emanating from the centre. But are they real?
Look at the image. How many dark dots can you see at the same time?
Happy Christmas to all of you! We are lucky to have the best (and nicest) readers in the world.
This post complements the Christmas post from last year, which is on a closely related topic. It is hard to get away from the Tethys.
I’m finally caught up on my VC reading, I’ve been behind for several months now. Perfect timing, as always Albert your Christmas articles are always such a standout! And I could read about the Tethys all day, every day… so never fear. Paleotectonics never ceases to amaze and fascinate.
Hope you had a wonderful holiday, and thanks so very much for my post Christmas gift of knowledge!
I saw the Messinian Salinity Crisis open for Porcupine Tree and Gojira at the Kingdom Hall in Paducah Kentucky. Good show.
they give Godspeed You! Black Emperor a run for their money 😀
Thanks for the great article and music!
I’m back!!!
Mery Christmas!
Kīlauea began to draining five minutes ago. This might be a new normal for Kīlauea for a few weeks.
Also, deflation just reversed to inflation, again.
Also, new webcam now.
Wow the drainback looks like a full hole in the ground with lava cascading toward it. Its exactly like some of the 1959 film that basically looks like a portal to hell. I do wonder seriously if you look down the vent how far down it goes. Its a wide open hole to the magma chamber.
First phase covered 2.6 km2 to 3 meters deep on average, so about 8 million m3 in 12 hours. Or about 180 m3/s effusion rate on average. The second episode that just ended lasted longer and didnt cover as much of the floor but looks like it built perched ponds. The first phase probably in reality was much faster than its average for the first hours then slowed down to the same average as stage 2.
Should say too that this measurement would make it the fastest eruption since 2020, maybe even fastest opening of any historical summit eruption at Kilauea although I havent checked 1967. In half a day it erupted about half of the total volume of any of the 2023 eruptions that were all much longer.
I guess too, now this is going to fill and drain, the actual final volume of all this might not get much more than 10 million but the volume erupted cumulatively could get much larger. Of course that huge cumulative volume in reality ends up back in the magma chamber and pressure increases, although it might not increase in pressure overall immediately as was the case in 1959. Its likely there will be a significant eruption on one of the rift zones within 6 months, but before that we get another nice lava geyser 🙂
Thanks Albert for a marvelous Boxing Day read (Ncl being far, far to the east of most of the VC community!) I’ve done lots of work with NaCl and with gypsum, it all chimes very well with my experience. (We tend to use calcium chloride since it is much more soluble than sodium chloride – but you have to exclude sulfate or it will come out of solution as anhydrite – which is the astringent sister of gypsum.)
I had been wondering if there is a subduction zone SW of the Iberian Peninsula, as I’ve seen data from time to time which suggested that. I was interested to see if thrusting might’ve lifted the Gibraltar area thus closing off the entrance to the Med. Searching does find an incipient subduction zone, but that would not have been active at 5 Ma. But via the search I found a nice visual tool for subduction zones from the University of Montpellier in France:
https://submap.gm.umontpellier.fr/maps-index
You just drag the square box on the map to wherever you want on the globe, select the features you want like “Relative Subduction Velocity” and hit the “Generate Map” button. It’s pretty cool.
Indeed there seems to be some subduction in or around the Azores–Gibraltar transform fault (AGFZ) and the Alboran Sea between Andalucia and Morocco/Algeria. On top of this there seems to be a slab of the ancient ocean Tethys left there. This would explain the subduction. It would then have been active 5 Ma, even more active then. I cannot see any other eplanation as ocean crust is subducted when it is very old.
Seems the fountain was high enough to produce some tephra.
https://www.usgs.gov/observatories/hvo/news/photo-and-video-chronology-december-25-2024-kilauea-summit-eruption-pauses
Yes it made a lot of reticulite, the fountains yesterday were over 100 meters and on the KW cam were still obscured by the crater rim. At the start of the eruption KW cam had the fountain clearly visible, so possibly between 150-200 meters, hence the tephra on the rim I guess.
Seems drainback is only at one vent, the others formed on the original dike but may have only reopened as satellites of the drain vent the second time, so might be intermitent or die completely in future phases. I expect fountains to get higher as this goes on but maybe gaps between phases to increase too.
It is so typical for you, Albert, to sit down around Christmas and prepare such a nice informative and decorated article as a present for your readers, thank you very much and Merry Christmas!
This I didn’t believe: – The Mediterranean Sea is 4000 km long, equivalent to the entire breadth of the USA.
But you are right as always. The sistance from Tétouan, Morocco to Kairo, Egypt is about the same as from DC to LA.
The explanation for the names of the Red and the Black Sea is great. So our Mediterranean is the White Sea. Have to walk the dog and then continue the reading. Nice Boxing Day Literature.
By tradition, we do a post on a topic that is too large/complex for a normal post. And Christmas is a great time for family and friends, but it can be a bit lonely for some. It may help to have something interesting to read. So look at it as our Christmas gift to our readers.
“We don’t quite know which mountain was the southern pillar”. Basically the Southern pillar should be Monte Hacho on the Peninsula de Almina near Ceuta. It might have been know as Mons Abila in the ancient, but this is not sure. Altogether it seem to be unknown whether the so-called pillars were here at all.
Thank you for this interactive map, very interesting:
https://maritime-forum.ec.europa.eu/contents/map-week-submarine-volcanoes_en
There are astonishingly few submarine volcanoes in the eastern part and a surprising amount of activity in the Alboran Sea. Most submarine volcanoes are in the Tyrrhenian Sea thougk north of the Aeolian Islands with Stomboli, Lipari, Vulcano 😉 and others.
“It [Tethys] finally reached the newly formed Atlantic ocean”, addition: And went on westward passing between bothe Americas and was still open when the meteorite hit. it went all around the world joining the Pacific Ocean and the newly formed Atlantic Ocean and was first closed in Asia when India collided with Asia about 33 Ma after a first collsion with a Tethys island arc 55 Ma.
“Eventually this should close the Mediterranean Sea and bring to a close the era of the Tethys. But it may not. The Tethys has managed to avoid this fate before. It does so by rifting at its southern edge, creating a new ocean crust. Will this happen again? The only sign of any rifting is south of Sicily and it is very minor. Could it grow? Perhaps more likely, could the Red Sea finally get its act together and grow west, into the Mediterranean? ”
Agreed. Another idea. When the Somali Plate becomes loose Africa might rotate clockwise having more room in the south. It is pretty tight up there esp. in the north-east. The African Plate is not India. It doesn’t fit in nicely, so another solution might be found by plate tectonics. Spain also might become loose again although this is less probable because of the tight suture od the Pyrenees.
If Africa rotated clockwise Gibraltar might close and we would get back to your idea with a larger Red Sea which has a spreading ridge anyway. So the reconstructed part of Tethys would be the Indian Ocean part. As there still seems to be a portion of good old Tethys in the Eastern Mediterranean this looks very promising. Earth might reconstruct one of its eternal oceans in the deep future. Panthálassa has always been there in the form of the Pacific Ocean.
“The northern channel (the Betic corridor) ran from south of Seville to Valencia.”
This doesn’t seem to be correct. As your nice maps shows which is similar to this one (link) and would maybe be better positioned here (time-saving), the Betic Corridor ran from what is now Alméria in the east to Sagres, Portugal in the west. Valencia is in the meddle of Spain’s east coast, Sévilla is further east that Sagres and more inland, connected to the Med. Sea by the Guadalquevir, the river that the seafarers used to get from Sévilla to the Med. Sea.
https://www.researchgate.net/figure/a-Geological-map-showing-the-location-and-geometry-of-both-the-Beticand-Rifian-Corridor_fig1_348995245
Better positioned: I meant your own map further up in the piece.
“In fact we are ourselves have caused just such an event,” — I contest this. We might accelerate it though. On the first map in your piece about the Aral Sea however it is clearly visible who is culpable: 1. India and the Collision, 2. The African and the Arabian Plates moving north-east. The Aral Sea and also the Caspian Sea are parts of Tethys that were cut off the ocean flow. With more travelling north-east of the above mentioned plates they will possible dry out completely and become deserts like many old parts of Tethys (Sahara, possibly Gobi, Libyan Desert and possibly Mojave).
We can only accelerate the process or stop the accelaration, but we wouldn’t stop the process. Only the breaking-off of the Somali Plate and a rotation of Africa would bring it to a halt maybe.
On the other hand – in case we are responsable for global warming – it might become subtropical around those seas and rain more which would enlarge them.
I think that rapid overflow above the Gibraltar barrier is what people like just as much as the sudden death of all dinosaurs, very sensational, nice possibility of films with today’s tecjniques.
The Mediterranian Sea might have been refilled more gradually, i,e, after the end of a possible glaciation. As the second article in the link here shows there are hidden surprizes in the Antarctic Ice Shield which is certainly difficult to explore.
“Now, researchers have dated ice that’s a staggering 6 million years old. It offers the first direct glimpse of the Pliocene epoch”,
https://www.science.org/content/article/scienceadviser-6-million-year-old-ice-sheds-light-earth-s-climate-ice-age
The end of a glaciation would mean a) That the sea levels rose like you mentioned, b) that the Med. Sea would also have been filled with melt water from the Alps, The Appenine and the Atlas.
a) would mean an overflow, but not to that sensational level. In case of a warmimg phase there would also have been more rain. We are allowed to look back at Libya about 15/16 months ago. There were no dams back then, the Nile is the longest river of the world with a drainage area of 3,254,555 square miles, but a small drainage volume which, after a cooling phase with a warming period might grow. And no dam between fighting Ethiopia and Sudan plus Egypt would mean a lot more volume. Rwenzori Mountains might have had larger glaciers.
Too many possibilities to believe in a sensational scenario. Earth is too slow to create many sensations aside from volcanoes and tsunami.
At the end you mention Tethys again. As the Valley of the whales shows there were several drying periods
https://iugs-geoheritage.org/geoheritage_sites/whale-valley-cetacea-and-sirenia-eocene-fossils-of-wadi-al-hitan/
There might have been a long subduction and drying period of the Tethys Ocean, and a part of it still sits in the Eastern Mediterranean. This process might have added to the salinity crisis.
You helped making my Boxing Day (Children have left me alone with the dog – we are uttely bored now) interesting, thank you again.
Hi Albert,
read last Christmas’ piece again. This year’s tops it for me. For the next year I want to give you an idea which also seems to be a nut hard to crack:
“Based on plate tectonics acting over millions of years, the “gravity hole” is believed to have been caused by fragments from the sunken floor of the much older TETHYS OCEAN in the narrowing gap between India and Central Asia, as the sinking fragments were offset by mantle plumes of lower-density hot magma from the Earth’s interior”
https://en.wikipedia.org/wiki/Indian_Ocean_Geoid_Low
Happy holidays to everybody!
The tiltmeter ESC at Pauahi Crater, it shows an abrupt change in direction with this eruption. Pressure us definitely being increased in the magma system by the drainback even if the actual summit tiltmeters dont show that currently. Im a little sceptical on the advanced longevity of this vent beyond a few months now, its likely to head east more than significantly fill Halemaumau. But thats speculation, more certainly I think the next phase starts within 12 hours time from now (2:46 AM HST)
The cycling between eruption and draining was also seen towards the late phase of Fagradallfal number 1. It has to do with gas being lost quicker than the magma provides it, and once the gas runs out the lava level goes down.
Usually I think it has to do with a snowball effect between the nucleation of gas in the conduit making magma lighter and the speed of the rising magma, eventually breaking down when pressure is too low. In this case, degassed lava trying to invade the conduit from above makes it a bit more complex
Did the magma that erupted on middle ERZ in September migrate back during last months towards the summit area? Maybe we have a period, when there is a movement there and back from ERZ to summit.
I doubt it, there is pressure exchange but magma physically can probably only flow one way, with exception to the rift conduit that this tiltmeter sits near the end of. An exception might be if there is a deep caldera abd it starts filling then the ERZ probably does backflow, as in 2020 when the summit filling started. But there is also south flank sliding too so the apparent deflation at Pu’u O’o seen after late 2021 up to this year might not be magma backflow but rather just absense of magma flow into the ERZ and the south flank moving away still resulting in subsidence.
Whatever it is though now Halemaumau is too full, pressure will rise in both the ERZ (and SWRZ) connector and under the caldera together, until one of the rift connectors breaks, which might take weeks or might be years, depends on how this vent goes but im not expecting the latter.
1974 they analyzed the eruptions this way:
“Despite their distinct individual characteristics, each of these eruptive episodes was related to underlying, common magmatic processes that affected the entire Kllauea summit area in the latter half of 1974. Deformation of the Kllauea edifice and the distribution and character of volcanic earthquakes show that the magma storage areas migrated westward beneath the summit region in 1974: from the upper ERZ, to the area between the uppermost east rift zone and Halemaumau (July), to Halema’uma’u and the west (September), then into an area between the western KFS and the upper SWRZ (December), with subsequent intrusion into an area south and southeast of the SWRZ (early January)”
They observed that “magma storage areas migrated westward from upper ERZ to … the west” including upper SWRZ. Where and how can the magma storage areas migrate?
This migration from the upper ERZ to the western summit area reminds me to the trend 2024.
The storage doesnt migrate, the whole magma system is the magma storage, the area actually getting supplied magma changes. From 2020 to late 2023 it was mostly Halemaumau getting fed, then late 2023-mid 2024 the SWRZ got filled, and then mid 2024- about a month ago the ERZ got partly filled. Now it seems all 3 are probably filling but the summit is the easiest path.
The ERZ isnt full, the middle ERZ might need about twice the volume it actually got so far to fill up completely to 2018 level. And the part just beyond Pu’u O’o probably needs almost a full refill. But it us likely getting magma to go that far east needs the summit filled to a high level and it wasnt there yet. The floor of Halemaumau is 940 meters elevation roughly and it was about 100 meters higher in 2018 before the eruption. Filling the whole crater by another 100 meters now will take a few years even with the recent huge supply Kilauea has.
I can see it maybe having eruptions along the SWRZ and upper ERZ or elsewhere in the summit in that time but a major ERZ eruption and new shield I no longer see likely before 2030, although it is very likely to actually some point in the 2030s. This vent now I think will function very similar, though, and may create a lava shield in Halemaumau like Halemaumau itself was in the late 19th century. And a lot of fountains, maybe huge ones 🙂
I have also thought about whether the location of the new vent can become the place for a future lava lake comparable to the 2008-2018 Halema’uma’u lava lake. We have already seen how magma came up and drained down in cracks. If the dike succeeds in creating an open conduit, this may become a sustained vent where a lava lake becomes possible.
2008 the opening of the Overlook lava lake vent was preceded by explosive activity. https://www.usgs.gov/volcanoes/kilauea/science/chronology-kilaueas-summit-eruption-2008-2018 Very different to the recent purely effusive eruption.
I think it is very likely to become a new lava lake, although it would take years to become something like the 2018 lake. The Overlook lake formed while magma could flow put the ERZ, and both Pu’u O’o and Mauna Ulu only evolved into lava lakes when each if them formed flank vents. In 1960 the Kilauea Iki vent also erupted ash at one point but didnt reopen, but this might be the same idea.
Basically, this vent will probably be more of an episodic ventthat overflows or fountains, until there is an eruption on the flank that lowers the pressure and lets the summit vent collapse into a pit crater. This was also what happened to Halemaumau itself multiple times.
S2 camera shows a very small fresh lava flow from the furthest right small vent on the wall:
https://www.usgs.gov/media/webcams/s2cam-view-halemaumau-crater-summit-kilauea-view-west
well spotted!
Might be a new episode beginning to happen…
There is a little noise starting on the seismometers around the area.
This is SDH, RIMD and KKO also are showing.
Thank-you for the explanation of the natural history of the Mediterannean Sea, Albert!
The Mediterannean Sea has an impressive deap low at Calypse Deep with 5km. That’s a deep as the Pacific ocean around Hawaii. It reminds to the oceanic past as part of Thethys ocean(s).
With the small exit towards the Atlantic Ocean the Mediterannean Sea reminds to “lake-like” seas that only have small bottle necks to the oceans: Hudson Bay, Baltic Sea, White Sea (south of Kola peninsula). The Baltic Sea hat the opposite story of the Mediterannean Sea: It is in the center of the Baltic Shield. The Baltic Shield once was a mountain chain like the Alpes or Himalaya, that later was eroded completely. While the Mediterannean Sea is a sea, where before was an ocean, the Baltic Sea is a sea where before was continent.
Are there Black Smokers in the Mediterannean Sea? Are Black Smokers comparable to Fumaroles on land? Vulcano and Campi Flegrei have Fumaroles. So it wouldn’t be a surprise if something like this happens below the sea level.
The only thing that is needed to make the entrance larger is some massive earthquakes in the Rif or the Betics. And well, Morocco has massive earthquakes.
Map from Albert’s piece, upper third:
https://i0.wp.com/www.volcanocafe.org/wp-content/uploads/2024/12/word-image-16992-4.jpeg?ssl=1
Although earthquakes could also lead to a closure. 🙁
I don’t think that Black Smokers (New submarine volcanoes in rift zones) and fumaroles (chimneys in dormant or active volcanoes that release gas) can be compared. I added dormant as Mount Damavand has fumaroles, but is considered dormant.
If I’m wrong, Albert or Chad might specify or correct this.
It is like geysers: they occur where the magmatic system is very stable, to allow a water circulation to establish. geysers occur where the risk of an eruption (other than a water one) is minimal.
A little spatter visible above the crater wall…
The small spatter cone north of the main fountain is erupting persistently but really slow. Its definitely not erupting at supply rate, but does show that the eruption isnt over yet at all. It seems very unlikely to just stop now, I am guessing in 2-3 days another fountaining episode will begin as the tilt recovers.
I do remember this exact behavior was described in 1955 and 1983 which were both eruptions with a long pause after the initial eruption that then resumed, there were often very small but persistent vents active while inflation resumed and ultimately voluminous eruption picked up again. And in 1959 the vent looked completely dead after phase 1 but restarted after 4 days with no activity, and actually often Pu’u O’o and Mauna Ulu were quiet between fountains too though not always.
Lava effusion from the north spatter cone, while the main fountain vent is glowing and seems to be an open hole.
The Future Is Wild did cover a hypothetical future drying of the Mediterranean in 5 million years time, complete with speculative future animals.
https://youtu.be/IL1kL3xmZa8?si=LtTsxdWaIiUkbH1h
Im not sure about absolute dessication but I guess at some point the sea will be totally cut off with no hope. Im personally not convinced the Red Sea can stop Africa, it might reach the Med before they both close but its a short lived thing. I guess the long saga of the Tethys will end soon after, probably within 50 million years time, although the crust south of Crete is old Tethys seafloor so technically the sea still exists much diminished.
Ii would like to see a much more fleshed out The Future is Wild, with maybe only one time or even place shown but the ecosystem much more explored. I imagine a world probably full of things evolved from our livestock and pests, and maybe ourselves too. Our warming no matter the severity might only create a greenhouse world for half a million years, followed by return to glacial conditions, that is a lot of potential for rapid evolution.
To quote a Danish saying, making predictions is very hard, especially if it is about the future.
It is easier to make conditional predictions (“if …, then …”) than unconditional ones (“it will be …”). We can’t predict who will win next Champions League or Premier League Title, but we can predict, what will help.
“The existence of an earthquake and volcano zone recently located on the eastern coasts of Africa confirms this. Scientists estimate that the splitting of the African continent is happening at a speed of 0.25 inches per year. At this rate, the separation of tectonic plates could occur over a period of 1 to 5 million years.”
https://essanews.com/africa-slowly-splitting-in-two-how-somali-tectonic-plate-is-set-to-reshape-the-continent,6984991873886337a
My bet: It won’t dry out, but open up to the South. Champagne in heaven? If I win it’ll be on my order. In this case I’m keen on winning. Save the Mediterranean! I’ll sit on my bench up there and will see Tethys come back.
The bet is easy as all will end like it started. When the sun becomes too hot for mammals there will be giant reptiles again. For a while. Then Earth will start boiling. It might be a round cycle.
Kilauea is now erupting throwing lava bombs!
https://youtu.be/paa3RH0mXVo
Usually sedimentation in a drying/dieing sea begins with limestone, followed by gypsum and salt. The shores of the Mediterannean Sea show a lot of limestone in many varieties. Malta consists purely of limestone. The Balkans have a lot of limestone with interesting and beautiful karst effects. Limestones of the Alpes are witnesses for the Thethys ocean. The karst effects of limestone mislead some early historical scientists to assume that we live on a Nepunist earth which has water instead of “fire” below the earthcrust.
How was volcanism during the Messinian salinity crisis of the Mediterannean Sea? During that time Stromboli would have been an impressive high volcano inside the large and salty “Dead Sea”. But five to six million years ago was long before present Stromboli.
Stromboli has been active for the past 2.300 years – some say up to 5.000 years, and it is assumed that the edifice is 40.000 years old. So, Stromboli wasn’t there. No Aeolian Island was there. It is assumed that the Thyrrhenian Sea opened as a back-arc basin around 5.000 000 years ago (5Ma).
Oops – the number. That was possibly after the salinity crisis.
Something would have been active. There is a strong possibility that Corsica and Sardinia were active volcanoes.
Besides the volcanoes of Cantal (appeared between 13 million and 3 million years BP), the volcanoes of Devès-Velay (between 13 million and 1 million years BP) and the volcanoes of Cézallier (between 6 million and 3 million years BP), all in the Massif Central, France.
Possibly also some volcanoes further west in the Pyrenees. Maybe also some edifices in the Atlas mountains. I didn’t look that up.
It was a totally different landscape. Probably beautiful edifices like Stromboli, heavily eroded today.
Pic du Midi d’Ossau, ancient volcano, Pyrenees:
Corr.: Tyrrhenian Sea
Btw, just an example of beauty and maybe a very bad example. This edifice ist the rest of a volcano that was active in the Perm. It is sitting in the middle of other oldies (up to nearly 500 million years of age) in the axial zone. The whole complex was once sitting on the north-western border of Gondwana and then in Pangaea.
Stromboli is much closer to the epoch of the salinity crisis than this guy, only the other way around 😉
Figure 9, volcanoes of the western Mediterranian:
Article can be downloaded and is interesting:
https://www.researchgate.net/figure/Geological-map-of-Corsica-and-Sardinia-after-Cherchi_fig5_43499953
There is a lot of limestone in the region but it tends to be much older.
Yes. Limestone can of course be older.
The characteristic material for Tethys are Ophiolites, a mixture of ultrabasic rocks like olivine or serpentinites from the mantle together with oceanic crust and sediments. They are found in places around the Mediterranean like Oman, the Spanish coast up to Ronda and other places that had subduction and are a sign for subduction in the past. Subduction was certainly not everywhere, similar to the Pacific Ocean. The Ring of Fire has gaps like California (terrane) and Canada.
Limestone is often a sign for a history under water, but it is not specific for just one ocean. I got the idea that limestone with a longer history under salty water tends to become red, some at least in the sun, while travelling. Up to now I was too lazy though to check whether some people who can come along with some evidence have had the same idea, say scientists. In the Grand Canyon that’s to say its rocks (Canyon from Colorado River – possibly larger after the end of Younger Dryas) the Redwall Limestone has definitely a long submarine history.
And this history would include the Three Plates Pacific plus Panthálassa.
A propos Olivine – where is Jesper?
Did Jesper become famous?:
https://universemagazine.com/en/first-meteorite-crater-found-on-io/
We are very proud of him!
Rightly so. Seen by now that he wrote here last on Dec. 24th. Nice guy.
OT, but that site is doing something wonky with its images that is preventing them from showing up in Firefox. (Let me guess: tested only on Chrome?)
Specifically, instead of the image being a simple jpeg file I see this as its “address” when I “view image info”:
data:image/svg+xml,%3Csvg%20xmlns='http://www.w3.org/2000/svg'%20viewBox='0%200%20952%20543'%3E%3C/svg%3EThere doesn’t seem to be an actual link to an .svg file, just to the specification? Meanwhile the alt text has this:
Sure enough, if I paste that into the address bar I get what looks to be the intended image.
So why have they done this weird thing instead of just img src= and the latter URL, which would Just Plain Work(tm) in all browsers on all devices, and put proper descriptive text in the alt for people with visual impairments and screen readers to benefit from it?
The way they are doing it now a) breaks on current builds of Firefox, leaving a big empty space where the image should be on the page, and b) is not as good for accessibility by the disabled. As well as being just plain weird, when there is a thirty-year-old generally accepted straightforward way to embed images in web pages that, as I said before, Just Plain Works(tm).
Oh, lovely. WordPress decided to turn that into an embed even though it was in code tags. F&@!ing idiotic.
The URL I am referring to appears if you mouse over the image. Well, it does on a PC. If you’re on mobile I guess you’re screwed. 😛
Looks as though a magmatic intrusion may have resumed or restarted around the area north of Fentale in Ethiopia again, there’s been more M4.0+ earthquakes occuring there over the past week, albeit a different depth this time I think.
Is it a dangerous volcano?
The central volcano maybe, it looks mostly effusive but there is a caldera so could be explosive too. But the actual rift now is north of there, im not sure why GeologyHub has said it us a rhyolitic intrusion, at 9 km deep would probably be olivine cumulate that would be similar viscosity to granite mush but a dike able to erupt at this location would be mafic. An eruption in Awash national park would be a basaltic fissure eruption maybe moderately explosive but mostly harmless. If it sets off or otherwise involves the main Fentale volcano then that could be more serious. But it would need to be a very big eruption to be a danger to Addis Ababa, which doesnt seem like a very plausible outcome.
To be honest I think we will see it erupting soon, and probably pretty suddenly when someone goes over there after it already starts. Not sure how many people live close enough to see it immediately, or if internet access there is good enough for quick reporting.
But an event like this in Hawaii or Iceland would have us basically putting predictions to the day it happens, I would definitely put Fentale on my list of volcanoes to do a 2025 eruption, personally.
In the middle of Awash-Park, National Park. Among other animals, home of: Nile crocodiles, Rock pythons, Saw-scaled viper (Echis carinatus pyramidum), Puff adder (Bitis arietans somalica), Rhombic night-adder (Causus rhombeatus), Black mamba (Dendroaspis polylepis antinori), Eastern pallid spitting cobra (Naja mossambica pallida), and Black-necked spitting cobra (Naja nigricollis).
Just mentioning them because they might flee like in St. Pierre (Pelée 1902).
Only about 100 miles east of Addis Ababa, which is a very large city.
Here’s a close up of the swarm on USGS’s earthquakes map. That’s eight M4.4 to 4.9 tremors in a week.
Looks like there’s been quite a few since the 27th too. If there’s that many M4.0+ earthquakes I suspect there’s a significant amount of smaller quakes that we can’t see listed too.
current situation, recent insar image:
Wow, yes there is definitely something going on for sure. I wouldnt actually be surprised if someone finds a tiny flow or something out in the rift that erupted unnoticed, looks like the intrusion was relatively shallow to cause so much movement.
That black area near the end is lake Basaka, and Fentale itself is just north of that lake directly, so the intrusion does directly involve the central volcano and not just the rift zone north of it. Definitely a good chance of an eruption there now and probably of more rifting in this general area in years to come too.
Theres a big caldera filled with fresh black lava just southwest, I think it is Kone volcano, and if so both it and Fentale erupted together last time in 1820, I think that was already mentioned here somewhere. Next to Kone is Busat-Bericha which has basically no info or even a Wiki page but also looks like it has erupted pretty recently so might be a 3rd.
Thank you very much for the detailed explanation! 🙂
From HVO:
“Summit Eruption Observations: Webcam images indicate that the eruption within Kaluapele (the summit caldera) resumed gradually yesterday morning around 8 a.m. from vents on the southwest side of Halemaʻumaʻu crater. Very weak effusion of lava over the past day has produced small flows that remain close to the vent in the southwest portion of the crater. HVO geologists in the field this morning report sluggish oozing of lava from the active vent and no significant spattering. They also report numerous rockfalls from the crater walls.”
Interesting with the rockfalls, theres no strong tilting or elevated seismicity, so im not sure what would cause this.
Also the main fountain vent has opened again with spattering and a small flow, it took a few hours to starts properly fountaining after last pause so I think it we might get some action soon 🙂
I guess if pressure is the driver, then the tiltmeter will recover the pressure of starting episode 2 in maybe 2-3 days so maybe that is when major fountaining will begin, not in a few hours time. But its interesting that maybe gaps between episides wont be quiet then, Mauna Ulu was often active between fountain episodes and the same is true for Etna, as long as pressure still builds as it appears to do so now.
Also if maybe the northern spatter cone might be the dominant vent in the next fountain episode instead.
Thanks Albert! I have alway been intrigued by this event and I think you did a better job explaining it than anything else I have seen.
I know the POC and JKA Tiltmeters are offset by 18 degrees, but does it look magma is bypassing some of the magma Puʻu ʻŌʻō and transporting it further downrift? The POC has dropped 6 microradians to the northwest and JKA has risen 2 microradians to the west/northwest in the last month.
Eruption is definitely slowly intensifying, looking like it might start fountaining properly tomorrow even
Yes, the eruption continues. The lava field looks active, and behind a visual barrier we can observe some spattering: https://www.youtube.com/usgs/live
On SDH station gas release has resumed, while tilt is flat increasing:
?fileTS=1735391318
Yesterday Stromboli did a lava flow ~half way to the Mediterranean Sea: https://www.volcanodiscovery.com/stromboli/news/260894/Stromboli-volcano-Eolian-Islands-Italy-new-lava-flow-on-Sciara-del-Fuoco.html
Thank you. Nice pic.
Very nice article, Albert – Happy Holidays to you and the VC crew from coastal North Carolina. Steve
Thank you
Spurr seems to be rocking and rolling at the moment, anyone have any thoughts on it? GVP suggests it was dormant for several millennia after its most recent caldera forming episodes, and then recently woke back up to do repeat VEI 4’s.
Could Spurr be entering a rather prolific cycle of active, moderately large explosive eruptions?
I’ve recently thought about whether ash clouds from Alaska once have reached to Iceland or from Iceland to Alaska. Did the 1912 Novarupta Ash cloud pass to Iceland and Europe? It was very much in the north, were westerly winds should be able to carry ash quickly towards the east. It was like Krakatoa or Pinatubo in the latitudes of northern jetstreams.
This website explains a lot about Novarupta: https://avo.alaska.edu/eruption/novarupta-1912-6
“Volcanic dust and sulfurous aerosol were detected within days over Wisconsin and Virginia; within 2 weeks over California, Europe, and North Africa; and in latter-day ice cores recently drilled on the Greenland ice cap.”
“Within several hours ash fell on Vancouver, British Columbia and Seattle, Washington. The next day the ash cloud passed over Virginia, and by June 17th it reached the skies above Algeria in Africa (Fierstein and Hildreth, 2001).”
Novarupta is at ~58°N, comparable to Northern Scotland or Southern Scandinavia. But Jetstreams can move the ash cloud to very different latitudes.
I would expect it depended on the strength of the SPV (stratospheric polar vortex) that year in terms of how much ash was lofted east quickly and far enough to fall on Iceland; was Novarupta ash found in Iceland? That I do not know, but it’s a very short hop from Greenland to Iceland and Novarupta was quite large.
That said, I think Alaska and the Aleutians are due another VEI 4/5 event in the not too distant future. Just reviewing Spurr as a volcanic system has me wondering if it’s entering a prolific phase, since it was so inactive for quite a lengthy part of the Holocene. And then to wake up and do back to back 4’s in a few short decades – mighty impressive. Seems to be a potentially potent volcano.
Also, was Spurr’s caldera born of a traditional collapse event or was it more of a sector collapse like Bezymianny / St Helens? Seems it was quite a large event, regardless.
It’s probably unlikely that solid ash fall gets to Iceland. But I assume that it’s possible that ash particles in high atmosphere are able to get there and to disturb modern air traffic.
Yes, we have waited for some time for a real Plinian event. Most eruptions after HTHH were not more than Vulcanian to Sub-Plinian. But a real Plinian black mushroom Cb cloud is due in the world again.
Ruang was a VEI 5 plinian eruption this year. Was just at night so you see the massive lava fountain at the core of the plinian plume, where in the day it might be mostly grey ash.
Chad, what was the total volume of the two eruptions? IIRC it was two VEI 4’s that together breached VEI 5 classification, with the second being the larger of the two and nearly a VEI 5 itself?
I still see it frequently cited as a VEI 4 event, which seems unlikely (especially in summation).
I dont know myself but on GeologyHub he said one was like 0.9 km3 and the other similar a little smaller. Anyway the total is definitely over 1 km3. Splitting them is silly when there was only days separating them. It was for sure a VEI 5 and a plinian eruption.
https://www.facebook.com/share/v/15pURgqn5J/
Video of the lava fountain within the last few hours, its actually much more continuous than I thought though not very high volume yet. But I think it is slowly ramping up to a paroxysm in a few days, pressure is still growing.
Tsunami-like waves in Peru. No indication of possible causes. Link of live images below (in Spanish).
https://youtu.be/33sRVk3LR6o
BBC reports that “The waves are being caused by persistent winds off the coast of the United States, according to The Chief of Hydrography and Navigation for Peru’s Navy, Enrique Varea”
GeologyHub proposes a different version as to the cause of what he calls a “true tsunami”.
Link: https://youtu.be/TkD-Trt6cTcy
Video from the start of the eruption, showing the size of the lava fountains back before there was aby really good view otherwise. Really started off with a bang.
https://youtu.be/A9XLLEVVan8?si=vbERfZi_ITZyiAli
https://www.youtube.com/live/OuDDJaiwoLo?si=22Y-0AMb4FeC4XbI
Live view now, fountains are now much stronher though not as tall as last time yet. HVO said deflation started hours ago but tiltmeters only just started showing it, so fountains could still get much bigger if the output now exceeds the supply rate.
The daylight images show that there perhaps was a partial collapse of the western caldera wall. https://www.usgs.gov/observatories/hvo/s2cam-halemaumau-crater-summit-kilauea
The thermal webcam shows that the active lava field area has increased, it covers nearly a third of the covered old lava lake:
The lava fountain of Kilauea has risen again … with the “burning tree” in the foreground that reminds to Moses’ thornbush again.
Today Eldey is rocking, but probably a usual earthquake swarm. Would an earthquake swarm before and eruption like 1926 look much different?
That is quite the swarm, an M3.5 and a lot of of M1-2s today. Certainly if it was happening at Sundhnukur we’d be expecting an eruption imminently. Could it be a dike?
Iceland today is really quite something. Biggest swarm in a long time at Eldey and some very significant activity around Katla, plus a M3.8 at Bárðarbunga and a quite busy day for the Tjornes Fracture Zone. Could it be that there is some kind of rifting going on off of the Rekjanes Ridge and that is creating tension all along the plate boundaries? Not an expert so could be magical thinking
The recent quakes are quite weak and don’t have a ’99’ quality. I expect that the location has a larger uncertainty than normal. Once checked, it may turn out they come from a more focussed swarm
All the Katla quakes have very low quality and are probably false detections due to the Eldey swarm. Earthquake swarms like this are common at Eldey. It’s not unlikely that it would be related to the current rifting episode at Reykjanes, but it could also be business as usual for the Reykjanes Ridge.
Bárðarbunga is really interesting. Seismic activity has significantly increased during 2024, and it doesn’t seem to slow down. GPS stations KISA, VONC and DYNC seem to indicate that Bárðarbunga is currently inflating at an increased rate. It’s still decades away from recovering from the Holuhraun eruption, but despite that, it probably has a lot of magma in store. It’s worth keeping an eye on.
Is Bardarbunga more likely to do an eruption soon than Grimsvötn?
I don’t think so. I’d say the chances for an eruption from Bárðarbunga have increased, but if I had to bet on which one goes first, I would still put my money on Grímsvötn.
Iceland is going to get strong frost over New Year’s Eve & Day: https://www.ruv.is/frettir/innlent/2024-12-30-grimmdarfrost-a-gamlarsdag-431965
-10°C in Reykjavik, -20°C around Katla, -25°C around Hekla. A good reason to sleep or to awake for volcanoes?
Two quakes at a depth of 10 km today, one 4,9 14 km NW of Awash, a second one 30 km WSW of Awash in Metehara , magnitude 5. First one reported from VD two minutes later, second one just reported from German Research Ventre for Geosciences.
https://www.volcanodiscovery.com/earthquakes/quake-info/10058698/quake-felt-Dec-29-2024-Near-Addis-Ababa-Addis-Ababa-Ethiopia.html
“It is located adjacent to Awash national park, Lake Beseka, Metehara sugar plantation and factory where more than 50,000 people live. The most important and busiest highway and railway route of the country crosses the lower flanks of this volcano.”
https://etd.aau.edu.et/items/f77cf78e-4cc6-4962-b756-3c4f213a13cf
Volcano Kone is 30 km to the East and erupted last at the same time as Fentale (1820 +/- 10 years).
Centre of course. F***. Sorry, hate typing faults.
The depth sounds like the default value used when the depth cannot be measured. It could be anywhere between 5 and 15 km, to cover the most common range
Looks like a M5.1 has just struck there.
the situation explained by volcanologist, John Seach:
https://x.com/Gianfranco_AC/status/1873322534386692365
There was a strong swarm starting on September 27. This swarm lasted a month which is common for Ethiopian dike intrusions, it’s how long an intrusion in ~1400 AD lasted (attributed to Dubbi but possibly Alid volcano instead), and how long Manda Inakir was swarming in 1928. Then there was an almost full lull lasting two months when activity flared up again on December 26 and now we have a stronger swarm than the first.
So basically Fentale is doing a dike intrusion series related to rifting, similar to the present Sundhnúkur situation, or to the Krafla Fires, or Manda Hararo in 2005-2010. This is the second dike intrusion which it’s somewhat larger than the first. But the difference with Iceland is that little basalt erupts in the Main Ethipian Rift, rifting is probably almost entirely intrusive. I wouldn’t rule out an eruption, but the north rift of Fentale has probably rifted a lot of times in the Holocene yet doesn’t have any young-looking lavas. The best chances for an eruption would be for the central Fentale volcano to erupt, maybe a rhyolite eruption or some basalt from near the caldera.
https://ds.iris.edu/ieb/index.html?format=text&nodata=404&starttime=2024-09-01&endtime=2025-01-01&orderby=time-desc&src=usgs&limit=1000&maxlat=9.97967&minlat=8.48867&maxlon=40.60547&minlon=39.45190&sbl=1&zm=8&mt=ter
Brillant explanation of the situation, great the comparison to another rift zone, thank you v.m.
Also brillant map on Interactive Earthquake Browse. I also found that the lava there should have less silica, but not as little as the fast running lava of Nyaragongo:
https://www.volcanocafe.org/nyiragongo-and-its-ultra-alkaline-magma-part-iv/
Also, I know there were just some comments on it but Fentale is showing quite persistent unrest with regular large quakes at depth… The persistence suggests we may see something eventually happen here I’d wager, though probably more of a fissure eruption unless it were to involve the main edifice – that the current thinking?
Seventeen tremors between M4.3 and M5.1 in the last week.
Nearest volcano is Dofen with an eruption or several in the Holocene, no precise dates.
Now up to 28 tremors M4.4 or over in the last week. Including an astonishing 11 M4.4+ tremors in the last 24 hours. I suspect some of the earlier ones are now scrolling off the USGS seven day period as well.
I have no idea what is going on, I’ve never seen so many medium sized tremors in one place in such a short time.
Interferogram of Kilauea, there was no movement southwest of the caldera so seems this was a ring fault eruption not an eruption on the fissure swarm from Kilauea Iki to the SWRZ, unlike the last eruption of 2023. This isnt too surprising from the earthquake locations that went along the caldera fault more than anywhere else.
Seems like instead of a tall fountain this time there are two strong vents, and maybe the north spatter cone acting up again too. Output does look lower than episode 2 was though, I think probably episodes 1-2 were overpressure while now we are seeing the system more at equilibrium, only building pressure based on the degassed lava in the vents after.
It is actually a little like baby Pu’u O’o, it had quite low fountains and moderate effusion rate for the first few episodes after it was the only vent (episodes 4-5 in 1983) but fountains got stronger over time. Seems possibly the same now, relatively little overpressure and no mature vent yet. But in a few weeks I would expect a different situation. Im doubtful the eruption will end on its own now too, only when pressure is high enough to send magma down a rift zone.
Yes, it seemed likely considering where the vents were located.
After seeing the main vents were along the wall I thought the same. I think there must have been another fissure possibly an entire parallel dike that did open in the lava lake possibly where the 2020-2021 fissures did, but which died out and closed.
It is interesting how activity has been most concentrated in the southwest end of the 2018 caldera. It began there in 2020, and 2021 focussed there too. 2023 eruptions not so much but those were not so voluminous. And now again the southwest end is dominant. Even a century ago Halemaumau had become mature at the southwest end of what was a line of vents before 1868. So this general trend might have been ongoing ever since at least 1790, or even much longer. In the extreme case that the new vent builds a new cone and shield and actually does overflow the caldera I can see it only doing so at the southwest end within a decade but never getting to Volcano House without the vent moving. But thats a while off yet.
The old lava flow map of the summit (valid until 2018) shows that there happened several historical eruptions in the SW corner of the caldera. A famous one was 1919-1920. If the current eruption produces a high lava lake that afterwards drains in cracks towards SWRZ, we may get something like this.
“In late November 1919, the long-lived Halema‘uma‘u lava lake stood at a high level … On December 15, an eruption on the caldera floor just southwest of Halema‘uma‘u produced a small lava flow. More significantly, surface cracks opened in a southwesterly direction outside the caldera to a distance of 10 kilometers (6 miles) down the rift zone” https://www.usgs.gov/news/volcano-watch-1919-1920-mauna-iki-eruption-kilauea-volcano
2023 Hector posted an article about SWRZ: https://www.volcanocafe.org/kilaueas-triple-swrz/#:~:text=The%20events%20of%201919%2D1920,turn%20on%20November%2028%2C%201919.
Is it magma that caused last Pahala earthquake swarm on its way upwards? Today Pahala had a 4.3 earthquake at 30.78 km depth. Is it related to the events on the vents in Kilauea?
Probably not but I dont think we can be sure really, even after all this speculation its still pretty unclear how the Pahala quakes connect to Kilauea.
While getting distracted with the African Rift and browsing I found a beautiful pic (Wik.) of a volcano. Yes. It is, however, from the Precambrian (4,6 Ga to about 538.8 Ma), standing at a height of 8,625 ft. and is located in the south of the Sinai. I didn’t even know that the Sinai had mountains at all. I know that the Sahara has volcanoes, but that is from VC.
Nice fountaining today.
Making a sizable cone now too. I remember saying back in 2019 that this caldera will probably be very different by 2030 🙂
There is a sticky looking lava flow near B2, lava that was ponded in the flows from a week ago that got pushed forward by advancing lava from now. Its not a push out from the lake actually.
Bravo, Bravo, Bravo for the Messinian !!
Famously featured in Turtledove’s ‘Bottom Land’ novella and as the apocalyptic finale to May’s ‘Many Coloured Land’ series.
And eg contributed Nile’s sediment retro-filled notch-gorge that beset construction of Aswan High Dam. IIRC, there’s a corresponding gorge beneath the current Rhone, but no dam to suffer the consequences.
Tangential, is there any indication of a ‘Canaries’ mega-slump coincident with the onset of Zanclean Flood ?
Having an immense tsunami, perhaps hundreds of metres tall, roar ashore would serve as an excellent ‘can-opener’, with ensuing mega-flood briskly removing *local* evidence…
😉
Heh. Outlander+Game of Thrones = The Pliocene Saga. It would have made a good TV series. Unfortunately, Julian May passed about 7 years ago.
That is an interesting suggestion. We have no data for the Canary Islands that long back (none of the current volcanoes existed, and the previous generations are deeply buried). The Lisbon tsunami reached a fair height in the region sof Southern Spain and Morocco.
The large, unidentified eruption in summer 1831 (VEI 6?) has been identified as Zavaritskii volcano in the Kuriles.
Thank you. St. Andrews, nice. Found an article about it:
https://www.dailymail.co.uk/sciencetech/article-14236299/Scientists-finally-reveal-cause-1831s-global-cooling-event-caused-crop-failures-devastating-famines.html
With all of these mystery eruptions and their significant climate ramifications being studied gives me the impression that the Tambora climate effects are underestimated.
Re the Eldey swarm, IMO has commented:
Seismic activity at Eldey on Reykjanes Ridge subsiding (RÚV, 30 Dec)
Looks like Eldey gets to stay the same size it currently is, at least for now.
Good picture, good paper:
https://www.sciencedirect.com/science/article/pii/S0377027317303670
Tenor in all papers I’ve looked at: Lack of research, lack of reports about eruptions in the past, hazards underestimated. Efforts should be made to acquire more knowledge about the area and install warning systems. This sounds easier than it is though:
“In January of 2012, a group of European scientists and tourists was attacked at Erta Ale. Five scientists/tourists were killed, and several others were wounded, while some were taken as hostages. For safety, we had to hire three AK-47 armed soldiers to guard us. So we made it up and down safely.”
https://photosafari.com.my/articles/erta-ale-volcano-the-devils-throne-room-and-gateway-to-hell/
From last link up there:
“I cannot even begin to describe the emotions that raced through my fatigued frame as my eyes feasted upon this amazing, gurgling, cauldron of liquid rock ….. after a gruelling 15 km, six hours trek in 48°C to 53°C heat to reach the rim Africa’s most active volcano.”
Well yes, it is in the Danakil Depression, one of the lowest regions of Earth, the Dead Sea being the lowest, the Caspian Depression the widest. Contrary to Death Valley or the Caspian Sea there is no winter.
BBC must have done a documentary film about it, here only some text: (About cruellest place on earth, that’s what you get with a continental triple junction and spreading ridge near the equator, basically the opposite of Iceland):
https://www.bbc.com/travel/article/20160913-inside-ethiopias-sizzling-cauldron
The neighbouring depression is Lake Assal, Djibouti. The lake is supposed to have had fresh water at some point in the past and is now salty (French study, see wiki-overview). So we can basically see the process developping in those two depressions with Assal leading, whereas Dankil doesn’t have water yet. The Awash River runs into Danakil, but dries out there.
https://en.wikipedia.org/wiki/Lake_Assal_(Djibouti)
ALBERT
You once said we could utter wishes about what we’d like you to write about. After you have already written a phantastic piece about Rwenzori you might be interested in this area. Could be interesting, esp. at a time with many tremors further south.
Denaliwatch I have actually been investigating the Afar area for a while, and had some Volcanocafe articles in mind. One of the things I noticed exploring this area in Google Earth, is that the basin of Dama Ali volcano used to have a lake filled up to the brim, likely during the African humid period, the are young pahoehoe lavas of Gabillema and Dama Ali volcanoes that formed lava deltas into the lake. The overflowing river must have run into Lake Assal and then the Gulf of Aden.
So that was probably, when Lake Assal was not salty due to that fact. Well you could as well write about is then. I’d be hugely interested.
VC is rich, three people have worked on the Rift, Carl, Albert and Jesper. Only 30 pieces. So if you were the fourth I’d gladly read it.
Wish you a good end of year and Happy New Year and the rest of the team and readers and commentators as well.
Thanks, and Happy New Year to you too Denaliwatch!
Maybe prwtty obvious but it looks a lot like Iceland, im not aware of any really huge effusive eruptions but then Iceland doesnt have VEI 7-8 ignimbrite supervolcanoes either so it evens out I guess.
Still, the length of some of the lines of cones makes me think eruptions of at least Holuhraun scale must happen sometimes, let alone the more certain large rhyolitic eruptions. I doubt Fentale will do a Holuhraun but something 10x smaller still is pretty big, and might follow with a VEI 4 or 5.
I do wonder if maybe the whole rift segment in that picture basically erupts all in a series close in time like at Reykjanes, separated by centuries of quiet. That might explain why the EARZ has generally been pretty quiet in the past century compared to how much volcanism is obviously possible there, except for Erta Ale and the Virunga volcanoes of course that are always active.
Good idea. Reykjanes has been quiet for a long time too. Could certainly happen.
The difference of temperature is striking. Iceland can have very moist and cold weather, the north of the EARZ is the opposite. Rwenzori though – as Albert described – can have torrential rain.
Link for others, not easy to find (one of Albert’s best, imho):
The Mountains of the Moon:
https://www.volcanocafe.org/the-mountains-of-the-moon/
https://i0.wp.com/www.volcanocafe.org/wp-content/uploads/2021/02/word-image-9.jpeg
pic source VC
I agree in that ignimbrites are probably Ethiopia’s version of the Skaftar Fires. Iceland calderas are mafic so they collapse in massive fissure eruptions, but Ethiopia’s calderas are silicic and collapse with ignimbrites. Ethiopia’s Vatnatjökull would probably be the Corbetti area with a bunch of the largest rhyolite calderas on Earth. However, I think Iceland is still more powerful overall in magma production.
I mean, of course a develloping triple junction and developping rifting.
see next comment
What took me to the strange question is the fact that there are only two spreading ridges, both south, the Pacific-Antarctic Ridge and the East-Pacific Rise which ends north of the equator though, in Baja California.
The rest is a large slice of Pacific Plate subducting in many parts (Alaska, Aleutes, Kamtschatka, Kuriles, Japan, Tonga Trench, New Zealand). So, from the point of view of mechanics there should be some extension somewhere. And the biggest mass sitting on that plate is Big Island. 33,500 feet for Mauna Kea plus a little less for Mauna Loa, another roughly 20.000 feet for Kilauea, and Jesper stated that there is even a depression in the seafloor which wasn’t his idea, but from NASA or USGS.
Might be stupid or not. Big Island though is probably the biggest weight and burden for an oceanic plate world-wide. I stepped once on a flat glass plate belonging to a picture frame. Ok it is only glass, but I am only some kilogramms. It burst of course. It is just unimaginable that the Pacific Plate can take that incredible weight of that island without giving in.
So I wonder what of course how the plate is dealing with that. But maybe my thinking is too mechanical.
The Pacific Plate has to bear all of the Hawaiian-Emporer Chain of volcanic islands and seamounts. Big Island is pushed up by the plume, but towards the northwest the weight of the seamounts lets them sink down.
Even if the aged Hawaiian islands are eroded over time, the mass can’t escape there. Also the mass of collapsed islands remains there.
Yes VP, but they are now heavily eroded and some under water. I get the feeling that not a single one had the size of Big Island.
Big Island reminds me more of Olympus Mons although Olympus is nearly twice as high. It just creates an image of enormity in my mind, more than for the seafarers as they only saw less than half of it.
Olympus is an enigma – I wonder why there was no caldera collapse. But that might be due to the low air pressure.
Clives Staples Lewis (Narnia, The Cosmic Trilogy) who was about the opposite of stupid and who died the same day as JFK, Nov. 1963 already, made Mars people high and thin. Ingenious really, considering the time.
There is a striking difference which lets Iceland seem more powerful. Iceland has everything on 103.000 square km which means a little more than 300 times 300 km.
The African Rift from the Afar Triangle to Mozambique has a length of 4.000 km, if we believe it or not. That would be the distance from Iceland to the Canaries, and we have many volcanoes in one place there in Iceland and in the Azores, some mighty ones with explosive charactre, some more effusive like Big Island.
Hector, one question that may be stupid: Can science be absolutely sure, that there is no triple junction under Big Island? I mean it would’nt be the first time. According to this map the first triple junction was about as far south of the Equator that Hawai’i is north. Just a thought as Big Island is a big mass, and there are also considerable amounts of sediment around the islands.
The bathymetry of the seafloor around Hawaii has been mapped even beyond the extent of the sediment-filled moat, this data is openly available, and there isn’t a mid-ocean ridge as such. There could potentially be some weak extension, that would be hard to know, but no ridge.
As an interesting side note, which came up while Jesper and I were talking about volcano stuff, Hawaii seems to erupt in the way that intraplate hotspots usually do, with a reduced number of volcanoes and most output concentrated into one. In Reunion it’s Piton de la Fournaise, in Comores Karthala, in the Canary Islands it’s La Palma, in Cape Verde it’s Fogo, in Hawaii it’s Kilauea (Mauna Loa before 1950), in Samoa it’s probably Vailulu’u, there’s always one dominant volcano that erupts most of the lava. But hotspots close or in mid-ocean ridges/rifts are much more complex, Galapagos, Azores, Ethiopia-Afar, or Iceland have a vast arrangement of volcanoes and it’s generally hard to know which volcano erupts the most lava, probably because of how magma starts to scatter towards numerous rifts, whereas in intraplate hotspots it sets up one successful conduit and just keeps pouring out of it.
There was maybe once in very distant past a time when the Hawaiian Hotspot passed through the Kuril-Kamchatka Trench: https://en.wikipedia.org/wiki/Kuril%E2%80%93Kamchatka_Trench
How would the Hawaiian Hotspot interact with a subduction zone like this?
Thank you. Sounds very reasonable. A good observation and excellent explanation.
VP, that might be a mistake on Wikipedia btw.
The Ulakhan Fault (which is a transform fault) and two trenches (subduction zones) is not a triple junction.
The triple junction is under The Chersky Range (between the Okhotsk, American and Eurasian Plates). As the American Plate has moved way under Siberia since a long time ago
https://www.volcanocafe.org/terra-incognito-the-verkhoyansk-mountains/
there is no way The Hawaian Emperor Chain has ever been a part of this.
The African Rift system is a beginning continental rift systems, while Iceland sits on an oceanic rift system, that accomplished the creation of an ocean. We still don’t know whether the African Rift System once will succeed or fail. If it will succeed, it will create a sea channel and later expand the Indian Ocean into present Africa.
A beginning continental rift like the present one in Africa behaves different to successfull oceanic rifts. We have to compare the current stage with failed continental rifts in the world. F.e. the North Sea rifts, the Oslo rift zone, the Jordan rift valley or the Rhine rift zones.
Do you people remember Nabro eruption in 2011? Don’t know if the post from volcanocafe is still available. It came out of the blue and created a messy ashcloud for all western Asia, a truly silicic eruption.
https://en.wikipedia.org/wiki/Nabro_Volcano
No. VC didn’t exist, and in the media it would have been on the fifth page or so. Pilots would remember. Thx
The East-African Rift is only partly continental as the Red Sea Rift that ends in the Dead Sea is counted with it. Therefore it is a mixed rift, and the Atlantic Ocean might have started like that.
The Atlantic Ocean is assumed to have opened in the south first. Those islands have moved away from the MAR in the meantime like Iceland will be two different islands in say 100 k years or so.
So I believe we see an ocean in the making and that is beautiful as we can deduct how the Atlantic Ocean was born.
Iceland finally did a record year with six eruptions (if we count them as single ones). It won’t probably repeat this high number again 2025, but I’d expect that we can get four eruptions. The second half of 2024 had two eruptions at Sundhnukur. If this rule continues, four eruptions for 2025 are possible. Additionally it’s possible that other volcanoes join the action, f.e. Badarbunga, Grimsvötn, Askja, Hekla, Krysuvik, Ljosufjöll, …
Looking at the Sundhnukur series: Can we expect an ocean entry? It would be the first Icelandic ocean entry of lava since Eldfell’s eruption 1973.
A new paper per the AGU suggests a new eruption on the Axial Seamount (off the coast of Oregon within the Juan de Fuca) is expected sometime within the next year (2025).
This area has a unique array of instruments unlike any submarine setting that I know of. The primary indicator, like in Iceland, is the rate of inflation and the total amount of inflation that immediately preceded previous eruptions. In this case, the inflation has now reached about 95% of what it was prior to the large 2015 eruption, and similar to previous eruptions in the 20th century.
We shall see. This is not the first time that pure inflation has been employed in previously unsuccessful attempts to predict an eruption, however this time the inflation has rapidly increased it’s rate just in the last year after many years of steady-state stability…so maybe this burst of inflation is a key. Though the depth precludes any major surface activity or tsunami, it would be interesting if an eruption did occur since it would serve as a litmus test for improving volcano eruption predictability…at least in this part of the world.
Here’s the abstract.
https://agu.confex.com/agu/agu24/meetingapp.cgi/Paper/1560361
Is that a reasons for the recent quakes?
Was in Basin & Range plus Mojave a few weeks ago and hugely impressed.
Happy New Year to you, California and Four Corner States!
Not sure if the recent MTJ quake storm is related to increasing activity/inflation over the Axial Seamount. The area is very seismic normally, and has been increasingly noisy beginning over a year ago… so it would seem to be rather susceptible to minor perturbations. Of note is the MTJ quake(s) is now casually being linked to “remote triggered” quakes north of San Francisco near the Clear Lake/Konocti Volcanic field and way east in the Basin and Range of Nevada near Yerington.
If there is any linkage to a future eruption on the AS, it would be that the volcano was very close to eruption anyway, and the soda bottle got shook up by the quake which just hastened the inevitable.
And Happy New Year to you and all the VC clan. Hoping for an exciting 2025 with lots of activity and nobody getting hurt! 🙂
They call it a “submarine basaltic hotspot volcano”. How independent from the “Ring of Fire” is this volcano?
I think the spreading Juan de Fuca Ridge is evidence of upward flows coming from the mantle..and a “hot spot” may just be a companion plume…or perhaps remnant material from the now-demised/subducted Farallon Plate? Technically, it’s in the area of the Ring of FIre, but the mechanisms for volcanism is not the same as inland (Cascadia)
That’s my guess.
Found this old post by Dr. Erik Klemetti in his Eruptions blog where many of us first met. It’s about Nabro. Will Fentale take the same path?
Enjoy!
https://www.wired.com/2011/06/speculating-on-the-2011-nabro-eruption-in-eritrea/