Theistareykjarbunga – Iceland’s Slumbering Giant

Carl / Originally published December 2011

This is a re-post of an article by Carl, written long before (in impatient volcaholic time-scales) fellow giant Bárðarbunga’s eruption.

The Five Large Volcanoes of Iceland

Mudpots in the Theistareykir thermal fields. Photographer unknown.

Iceland holds five volcanoes that in historical time have had eruptions transcending the 10 cubic kilometer mark during post-glacial times. The most obvious are of course Grimsvötn, Bardarbunga and Katla who share the same eruptive grounds for their large scale fissure eruptions in the area of rifting running roughly from Vatnajökull down towards Katla. There we find the Eldgja/Laki/Veidivötn-fissure systems. Among those Veidivötns Thjorsarhraun is the largest lava flow after post glaciation.

These 3 volcanoes are of the rifting fissure type (with that I mean that they have massive fissure swarms that rift, not that they are driven by rifting processes per see), have massive central volcanoes with huge calderas and massive systems of magma chambers. Normally they have frequent small scale to medium sized eruptions, and only have their large eruptions when the SIFZ (south Icelandic fissure zone) endures a rifting episode. Two of these are powered pretty much directly from the hotspot mantle plume under Iceland. The current location of the hotspot is believed to be close to Bardarbunga.

The two triple junction Behemoths of Iceland

The other two are different from the first 3 in many respects. Both of them are triple-junction volcanoes, driven almost entirely by rifting processes, are mainly fissure volcanoes with fairly unknown internal systems. Both of them are located fairly far away from the hotspot, and both are centers of unusually strong seismic activity for being located in Iceland. Both of them erupt in large scale when erupting, before going back to long periods of dormancy.

In southwestern Iceland we find Hengill, a large scale fissure volcano located next to Lake Thingvellir. The other is the northernmost of Iceland’s large sub-aerial volcanoes, just north of Krafla volcano. Theistareykjarbunga lies in the junction where the Tjörnes Fracture Zone (TFZ), the Grimsöy Oblique Rift (GOR), the Husavik Flatöy Fault (HFF), either directly intersects, or where they mechanically interact in a sense of it. Southwards from this the Northern Volcanic Zone (NVZ) comes running from Bardarbunga. Another thing to keep in mind is that Theistareykjarbunga is the northernmost of the main band central volcanoes of Iceland, and that it might have been responsible for the sub-aquatic eruptions out in Tjörnes area at the tip of its northern fissure swarm.

This of course creates tremendous tectonic strain that from time to time is released as massive earthquakes in the region. The last regional massive earthquake episode was in 1872 when 2 earthquakes larger than M 6.5 hit the Tjörnes Fracture Zone. During the last decades small but persistent quake-swarms have plagued the area.

Due to this a separate dense network of GPS stations where put up in 2006 for continuous measurement to enhance ability of calculating the pent up strain in TFZ and adjacent fault zones. It was emplaced and booted up in 2006. As a point of reference a GPS was placed on the believed to be dormant, or even dead, Theistareykjarbunga Central Shield Volcano, since this should be fairly stationary since it is almost dead center on the triple junction.

And for the first year that actually worked well. Then a continuous uplift started at Theistareykjarbunga with a maximum uplift of 30mm per year. This uplift caused concern, and the researchers then added additional GPS equipment directed at the volcano to get a better picture. Also other observational techniques were employed. Premier among the additional methods was the Envisat Interferograms that confirmed a circular uplift directly under Theistareykjarbunga Shield volcano. It confirmed inflation in a massive magma-reservoir with a depth of about 6.5 kilometers down, and covering an area of more than 70 kilometers making it into one of the largest on Iceland. And it is only logical that a Volcano of this eruptive ability should have a magma-reservoir on a large scale. Data and information taken from the article referenced in the end of the article.

Theistareykjarbunga Thermal Field. Photographer: Lara Stefansdottir

Theistareykjarbunga as we know it came into existence as a shield volcano in one majestic continuous eruption of Hawaiian type. The amount of magma ejected is sourced by Global Volcanism Program to be the largest in the history of Iceland. But it is actually so that GVP also states that Thjorsahraun in Veidivötn (Bardarbunga) is the largest effusive eruption in Iceland after deglaciation. I understand their confusion. They are so close in size that a competition is rather unnecessary, but on sheer effusive volume nothing on Iceland can compete with Theistareykjarbunga. But then one should remember that it was not an explosive event, and Thjorsahraun had explosive components, and was a lava flow, not a central volcano building event.

According to GVP there have been only 3 eruptions at Theistareykjarbunga, but that is most likely not true, there are more large lava fields belonging to both the southern and northern fissure swarms than they give credit to. But, it is understandable that they miss some, this is a very poorly researched volcano. A moderate number would be five large lava-field producing eruptions scaling in around 5 – 10 cubic kilometers, and the initial eruption scaling in on a total ejecta volume of 35 to 40 cubic kilometer if one combines the fissure eruption and the lava fields that was produced, and the part of the eruption that created the 30 cubic kilometer shield volcano. The last large eruption is well known, it was the 2700 year old Theistarekjahraun eruption.

Likelihood of Eruption

Theistareykjarbunga will most likely erupt. Big surprise. This is after all Iceland. Almost all of the active volcanoes will erupt many times in the coming geological timescale. So, just saying that it will erupt doesn’t mean that much really.

So what points towards an eruption? First of all the inflation points to an increase in eruptive risk, but there is also tectonic activity under the shield volcano that has a magmatic signature. And of course the sharp harmonic tremoring episodes that happened in October and November.

If one take into account these 3 signs it will give a certain relevance to assuming that the volcano is waking up from the 2700 year old slumber. It might of course still go back to sleep for a thousand years or more, one should always remember that.

But, if it continues to show signs, the inflation keeps on being steady, when would it then go? Well, at a minimum it would need another decade. But that is probably a way too short time span. We would need long periods of uplift, ever increasing quake swarms, continuing movement of the adjacent micro-plate. Regarding the uplift, we would most likely need to wait for meters of uplift to happen due to the immense size of the magma reservoir before it achieves critical pressure. Yes, we could have missed earlier large inflation periods down through the last 2700 years. But we should remember that Theistareykjarbunga deflated during the Krafla-fires, and that we still do not see enough quake activity for there being high pressure in the system. So I still would say that we need between a meter and five meters before anything happens. And that gives a time frame spanning between 30 to 150 years and the current rate of inflation. But, the inflation could pick up speed at any time too.

Time will tell.

How would an eruption look like?

Here we are leaving science totally. I admit being on skimpy ground when guessing when Theistareykjarbunga could erupt, but here I am putting on my psychic hat full on.

Bárðarbunga’s fissure eruption on September 4th 2014. The original image was one of Krafla’s 1975-1984 fissure eruption, however, the quality is low and this newer one looks much better. Source: Wikimedia Commons

The known eruption was effusive only, or almost effusive only. There could have been a bit of explosivity due to local hydrodynamic circumstances, but that would have been it. So if nothing has changed in the chemical composition in the magma reservoir, hydrodynamics, or in the chemical composition of the new magma that has been entering the magma reservoir, then it should be a Hawaiian type of eruption with lava fountaining, probably a fissure eruption either on the flank of the shield volcano, or out into the southern fissure swarm (signs from the harmonic tremoring make the southern part a bigger risk), it would be ranging from the 5 cubic kilometer range and upwards.

Sadly we do not know the amount of gas that would be released during an eruption. We quite simply just do not know enough today to guess about that.

Is there a risk that the system has changed? Could it be explosive? Let us start with the hydrodynamics. I do not think that the amount of water in the system have increased a lot since the last eruption, my guess would actually be that it has decreased due to land uplift after deglaciation, and a general drying out of that part of Iceland. On that reason I would say no. Could the chemical composition of the magma in the magma chamber have changed? Most likely. As time goes by magma changes chemically as it cools off and mixes with newly infused magma, and cools off again. Often this intermingling of evolved and unevolved magmas can produce magma types that can be fairly explosive. The magmas that was erupted before was low in Rare Earth Minerals, so they were not of the same hotspot origin as the Bardarbunga type that is massive in REM-content. And since the hotspot has not moved that much since the last eruption there is not much talking for it being another type of magma entering now, but this is just guess-work.

So yes, there is a very slight increase in risk that it will be a bit of explosive component during an eruption. But the average would be mainly effusive only. The scale of eruption though means that parts of the eruption probably would go as a VEI-2, or even a small VEI-3. Not much really if one count the scale of a likely eruption. But, the risk would be high gas content, and of course that so little is known about the volcano. Icelandic Met Office (IMO) will most likely keep an eye on things and expand the network around the volcano well in advance.


86 thoughts on “Theistareykjarbunga – Iceland’s Slumbering Giant

  1. No one talked about it yet.

    Hekla just had several earthquakes today. I have been wandering what this means, but knowing Hekla is Hekla, I think changes of an Hekla eruption are a bit higher tonight….

    Or, if similar to 2000, then this could mean the gentle run-up towards an eruption within the next few days.

    • Hmm, but since the false alarm of 2013, Hekla has been acting a bit differently seismically with quite a number of quakes this year, I’m not sure we can read that much into this for now, not sure if we can rely on quakes as a warning sign this time round, I think maybe the quakes could be a result of resettling due to the magma reservoir being particularly highly-filled compared the last few eruptions…

  2. About the possibility of Theista being responsible for sub-aquatic eruptions at Tjornes, what about the eruption there in 1867, could that have been from Theista? And has there been much happening at Theista in the last few years since the unrest settled?

  3. Besides Hekla, there are other interesting activity in Iceland.

    – West of Langjokull, a small swarm continues, this is an area where tectonic earthquakes can go up to M5

    – Trölladyngja, largest shield volcano in Iceland, north of Bardarbunga, and near the site where the dike activity began in 2014, has a deep swarm. Magma seems to be moving in there.

    – Finally, Krisuvik also had a small swarm, but this is not so special.

  4. Carl, from last post, what are your 8 supervolcanoes? I only find four.

    1 Toba
    2 Yellowstone
    3 Taupo
    4 Uturuncu (Altiplano-Puna complex)

    Toba and Yellowstone should not erupt anytime soon.
    Taupo and Uturuncu are the only ones that give me concern.
    Taupo is the most prolific of all of these but has erupted in a large way recently.
    Uturuncu shows outstanding inflation in a region famous for supervolcano eruptions. Uturuncu is probably the next super-large eruption. Question is how far in the future.

    • Well, if you found Yellowstone in that article you must tell me what you had for a drink. I only mentioned that it was a dead parrot pining for the fiords… It has gone with the dodo.

      And the APVC is not a supervolcano, it is an order of magnitude beyond that. There are though 4 APVC supervolcanoes listed as Active, and one (Uturunku) as a possible future supervolcano.
      1. Atitlán (Guatemala)
      2. Guacha Caldera (APVC)
      3. La Pacana (APVC)
      4. Pastos Grandes (APVC)
      5. Taupo (New Zealand)
      6. Toba (Indonesia)
      7. Tondano (Indonesia)
      8. Vilama Caldera (APVC)

      • I’ve found conflicting reports about the caldera-forming eruption at Long Valley, it’s either 600km3 bulk- VEI-7, or 600km3 DRE; about 1,300km3 bulk- VEI-8, so depending on which figure is the correct one, Long Valley could also be (correctly) considered an active supervolcano, so 9 in total. Do you know which figure is right?

        Also, about Yellowstone, we know it doesn’t have anywhere near enough magma to erupt now, but is it still possible that the Yellowstone Plateau volcanic field could eventually be able to reactivate, or is that it for the system until a new volcanic field of the hotspot is formed in southern Montana, or is even that not going to be possible, meaning that Yellowstone is sort-of extinct, as in there won’t be any eruptions ever again before the chambers completely solidify (obviously can’t be called completely extinct due to the hydrothermal systems)? And I don’t necessarily mean caldera-forming eruptions, but any eruptions full stop.

        • I pondered Long Valley quite a lot before writing the article. In the end I opted out of it due to the low eruptible magma percentage. That being said, it is a place where an eruption will happen sooner or later, but it will not be super again.

          Yellowstones magma is non-eruptible as a large eruption, but small eruptions of gas free drudge is still possible. Problem is that the magma reservoir has a very low percentage of melt and the melt is almost gas free. On top of that the driving force (hotspot) is entering a craton. It is as far as we know rather on the road to being dead instead of comatose.

          I was talking about Supervolcanoes able to supererupt, and that Counts out Yellowstone definitely. Long Valley could in theory reactivate as a supervolcano in the Deep future, but that is not evident now. As far as we know it was a one hit wonder.

      • To be fair, if we are going to categorize the APVC as more than one supervolcano, we should do the same for the Taupo Volcanic zone. The northern end of the TVZ hasn’t gone quite as large as Taupo proper, but I tend to believe that the entire TVZ has the potential to do what Taupo proper has done.

        Also, the TVZ northern end around Rotorua and Okataina has done some very large VEI-7 eruptions as well, with some likely potential to do VEI-8’s.

        • Not to give away to much, but the big calderas of APVC has gone of several times with VEI-8 eruptions, something that leaves poor Taupo quite far behind.
          But, with a very large bit of luck I will return to this next year. Both Taupo and the APVC 😉

      • The should be a 9. to be advised – i.e. the one we do not know about as it has yet to do its first VEI-8.

        The gnomes of Spamrah are back! – Admin

  5. Since some of our interest has recently been on the volcanoes of Hawaii (I won’t try and name any because I’ll get the apostrophes in the wrong place…), this new paper might interest folks: .
    It’s about the Emperor Bend and the hot spot motion. I spotted a summary of it on Science Daily.
    Thank you for the Carl paper!
    BTW Carl, did you ever get that Russian tank back to your Swedish home? It bothers me, that early Volcano Café memory….

    • I sometimes (once or twice) have a problem when it says I am logged in but reacts as if I am not. My solution is to log out first (confusing the hell out of it as it is trying to decide whether I was or was not logged in) before logging back in. Of course, this may not be the same as your issue

  6. The area around Kilauea has become more active since the 5.3 quake. There were around 10 quakes around Kilauea including a 2.9 .7mi and 2.7 @ 6 mi. Then a small group near the coast with a 2.9.


    • Trying smoked shrimp. But, the little buggers won’t stay lit

      • Is smoking shrimps the new thing to do in Florida after Flakka?
        I just hope that the people smoking the shrimp joints do not eat faces 🙂

        • No, the zombie critters don’t have the patience to smoke shrimp.

          Anecdotal: About 2 months after the Miami Zombie incident, I did hear of an arrested suspect in a nearby county that tried to gnaw on the hood of a patrol car while they were processing the crime scent.

  7. Significant earthquake in Turkey, close to the location of recent swarms of smaller events. It is not the fault line that runs through Istanbul but it could increase the stress there.

    • I’m curious about that sub-sea segment that recent papers have stated has not failed in a long time. Izmit might have trouble on the horizon.

  8. Query for Carl: Is the Cerro Galan caldera in Argentina considered as ‘live’, and if so has it VEI8 potential?

    • No holocene activity, but both Galán and nearby Cerro Panizos are not that well studied.
      What is Worth to remember is that both are part of the APVC. Note that both of them popped off 2.2 million years ago, the same as the others in my last article.

  9. Involcan have released a report about the recent seismic activity in Tenerife.

    Partly translated.

    ” Between Thursday 8 and Sunday 11 June 2017, the SEISMIC NETWORK CANARIA INCREASED SEISMICITY VOLCANO-tectonic in Tenerife and its environs. Thursday June 8 there were at least 10 earthquakes, being able to locate the hypocenters for 8 of them under the teide and at depths between 9-15 km maximum with a magnitude of 1.3.

    Events located in the area of mount teide in recent days, reflect a pressurization process of hydrothermal volcanic system, probably tied to the injection of magmatic occurring gases in the system. This process is especially apparent by the observation of the increase the emission of co2 diffuse in the crater of mount teide from November 2016, and already notified through the monthly bulletins involcan (

    The interpretation of the events of the 10th of June will need further analysis to establish their eventual relationship with current volcanic dynamics of Tenerife.”

    • This paragraph is about the energy released.

      ”Therefore, the SEISMIC SEQUENCE RELEASED IN 3 days about 86 % of the average energy in the same area.
      Similarly, if we believe that the sequence of the 10 June 2017 has released an energy of 8.7 X10^ 7 J and that the release of energy throughout the area of Tenerife in the previous year was 1.4 X10^ 8 J, we can say that this seismic sequence has released 62 % of the respect the energy released throughout the previous year”

    • Even though this set of earthquakes is a bit on the energetic side, it is still small compared to what could be expected prior to an eruption.
      Teide would most likely not be as noisy as Tanganasoga at El Hierro was, but it would still be quite noticable.

      • Could this new activity in Tenerife imply that Teide at this time is now awakening and that we could expect increased energy and perhaps the possibility of a powerful eruption .

        • It could just be normal hydrothermal activity, or it could be a small intrusion. Put this into relation of what Tanganasoga did prior to its eruption. This is still just minute activity and it will most likely die down.
          If and when it picks up big time it is time to start speculating.

  10. On the topic of calderas, I’ve noticed and pondered this formation around Murmungee in Northeastern Victoria while flying between Sydney and Melbourne.,146.6519309,26233a,35y,358.69h/data=!3m1!1e3

    It’s a roughly circular area of 9km diameter, surrounded by an escarpment at around 300 degrees of its circumference, and open to the Southwest. There is some speculation that it is a meteorite impact crater, but at this size, the meteorite must have been, as we say down here “A bloody big one”.
    The Eastern side are higher mountains forming foothills of the Victorian Alps, and it seems unlikely to me that a meteorite impact would have excavated a couple hundred meters off a mountain range. Though, if a meteor was big enough to gouge out a 9km diameter crater…

    As far as I can gather, it is filled with alluvial deposits, and the area was rich in gold, sparking a gold rush here in 1852. There are also diamonds to be found in the area, both of which tend to be associated with volcanism and alluvial deposits of eroded volcanics.
    The formation is part of the Beechworth area, a wine region which, along with large parts of Northeast Victoria is known to benefit from volcanic soils.

    The last volcanic eruptions in the Alpine region were about 25-44 million years ago, but as far as I have found, none of that volcanism resulted in caldera forming eruptions.

    Does anyone know more about this feature?

    • No I don’t, but one thing to keep in mind is that some calderas are subject to mineralizaion where percolating hydro-thermal fluids concentrate minerals to economically viable levels. Cabo de Gata volcanic field for example. Some of the calderas in it are well mineralized, some are not.

    • Probably just tectonic sources that made something that resembles a caldera-looking depression. With that said, who knows, maybe it’s some far extinct caldera being re-exposed by erosion? I tend to think that’s a bit of a stretch given the time period of 25 ma, but who knows.

    • from but I’m sure there will be on it in a paper or Oz geo site.

      The Murmungee basin is often misinterpreted as a meteor crater because of the crescent shape of the surrounding hills. The Murmungee flats form the base of the basin which is surrounded on three sides by range.

      The crescent ridge was formed somewhere between the Ordovician (490 Million years ago) and Devonian (417 million years ago) time periods. It consists of a variety of rock types, but one in particular, known as Granodiorite is a rare form of Granite. Geological surveys have suggested that Granite underlies the greater part of Murmungee Basin.

      The area is thought to have been formed due to selective erosion of the granite pluton which is now mostly buried. The only surface exposure of granite can be found on the northern rim of the basin.

    • Many hotpsots/weakpoints in the crust that we know of today as volcanoes could have been formed by impact events so I wouldn’t say the two explanations are necessarily mutually-exclusive.

    • Have seen a few similar sights myself when looking out the window of a plane when flying over Australia. In fact, that’s one of my favourite parts of flying, a past time if you will, noting what and where and doing the research when you land to find out what it is.

      Hoping to see this in daylight as have only flown over at night but the flight map has me intrigued! Not Australia though …

    • I did Geology years ago in Melbourne, I am long since gone from that field so my mind is a bit rusty on it. We did a field trip to the ranges north east of Melbourne and looked at Ryholite and tuff depots that were erupted in Caldera forming events.

      Eastern Victoria had many volcanoes during the Devonian Era ~350-400 Million Years ago. Mt Dandenong as an example and more north East of that.

      The Great Dividing Range (was formed in some part by subduction). So there were probably many volcanoes/calderas formed during this time, that are long since eroded and not obvious

      I am not familiar with the formation in the link you have above…but with 350 million years of subsequent changes..i doubt devonian calderas are obvious from satelite anymore.

      There was subsequent volcanism, but the Devonian was the most active time for Calder formation in Victoria.

      I think the most noteble later Volcanism was from a hotspot that drifted in a south-south westerly direction from NSW through central Victoria, Which started ~25 millon years ago in NSW. i think it has moved off the coast now and is not particularly active. It did produce the flood basalts of Western Victoria ~11,000 years ago.

      you will have to go out there with a geo hammer and crack few rocks open 🙂

    • Awful, awful fire. I worked as a fire marshal for a number of years and no-one, but no-one, should ever cut any corners with fire safety. And the advice for residents to stay in their flats goes 100% against fire service recommendations.

      • I just read -(Think it was the Daily Fail) earlier that there were no functioning sprinklers…
        Someone ought to swing on this one…

      • Our dingbats are reporting that a substance called “cladding” was responsible for the intensity of the inferno. Sympathy for the victims, but our “news” people are LITERALLY VAPID IDIOTS. Cladding is a functional purpose for a material. There are many differnt types of various compositions and are made for specific purposes. I’m guessing (since the news can’t give me any actual information) that some version of insulation or structural coating was used that is not suited for the purpose. In other words, some lawyer just made bank. You can always count of one of them popping up trying to feed off the free money.

        • It seems probable that the problem was the air gap underneath the cladding, which funnelled the fire upward.

          • I’ve been around a lot of fire and that thing chimneyed like nothing I’ve ever seen.. including a hilliside of dead lodgepole pine and a upslope wind..
            A friend of my wife and I- who was in the Blitz- as a child said that was way too
            familiar to her…

    • No, I am at home. But it was felt pretty good in Guatemala City. My wife woke up from it and she is a very Heavy sleeper indeed.

  11. a new crazy thought drifted through my mind this morning 🙂

    if there is decompression melting near the rifting at the red sea triple junction – or even just magma injection in the region, (presumably there is).

    what would theoretically happen if some rising magma that was going to just end up as a dike emplacement clipped a drilled oil field (there are several not that far away as I understand it)

    would the interaction of magma + oil be similar to water plus magma – giving something like a phreatic eruption ?
    if so would the pressure in the oil field increase and jet out of the wells – or are they sufficiently constrained?
    would you eventually end up with underground fire ? and would that decrease the strength of the rocks when the oil was depleted and end with something like a subsidence caldera ?

    Edward 🙂

    • You will get lots of methane. Something like this may have happened during the Siberian traps, and may have caused the lethal global heating spike (that was perhaps coal rather than oil). The remaining baked oil may form shungite.

    • Not volcanic in origin, but Coal Seam fires come to mind.,_Pennsylvania

      “Analysts disagree about the specific cause of the Centralia fire. Writer David Dekok concluded that it started with an attempt to clean up the town landfill. In May 1962, the Centralia Borough Council hired five members of the volunteer fire company to clean up the town landfill, located in an abandoned strip-mine pit next to the Odd Fellows Cemetery just outside the borough limits. This had been done prior to Memorial Day in previous years, when the landfill was in a different location.”

      Somewhat odd, but the setting of “Nothing But Trouble” (a comedy) was placed in the fictitious town of “Valkenvania” and featured a coal seam fire as one of the driving points of the plot. (Why the “Judge” hated “Bankers” with such zeal.)

    • Something like did indeed happen about 250 million years ago, and very likely contributed the worst mass extinction of all time prior to the age of humanity. There is evidence for fly ash, a highly toxic byproduct from burning coal, in deposits of end-Permian age in Northern Canada. Not unlike that emitted by coal-burning power plants today, actually. Many parts of Siberia are indeed rich in coal deposits, a fact that has not gone unnoticed during the Soviet era. It’s theorized that the Permian fly ash was the result of massive amounts of basaltic magma hitting the coal seams on the way to the surface.

      Imagine one fine day about 250 million years ago somewhere in what is now Siberia, when one day – BOOM, great clouds of inky black ash come blasting out of fissures perhaps up to tens of km long. Only this isn’t regular volcanic ash – it’s literally smoke from coal seams set alight by rising magma ahead of one ofthose massive flood basalt eruptions. The smoke gets injected at least maybe 10-15 km into the atmosphere – high enough to get into the stratosphere and get blown around the planet’s high latitudes (the Siberian Traps were centered roughly around 60-65°N at that time). Sunlight reaching the surface would’ve been cut down seriously, making things a lot colder than the local flora and fauna. It’s not just fly ash, but also very bad acid rain and more than enough CO2 to warm up our planet big time. This would have resulted in a massive die-off of large animals like Cynognathus on land and in the sea within a very short period of time. This could have happened not once, but at least a few times within a period of 750,000 years, especially if coal deposits were extensive/deep enough.

  12. Curiosity compels me to ask, is there an article on Hengill? If not, will there be? If so, where can i find it?

    • I’ve been around through various incarnations of the Cafe and have yet to see one specifically about it. It’s appeared in comments many times. I think there really should be one but I don’t have the knowledge base needed to do it right.

  13. In the last few days Mauna Loa has seen a sudden increase in extension of the caldera. This may be movement in the shallow magma chamber, probably magma moving around rather than coming up. There is also a little inflation but this is marginal. Interesting to see whether it settles down again, or keeps this up.

  14. Mainly for the US readers. You can stick your zip code in here and see a simulation of what the 21 August eclipse will be like from your location. From the looks of it, I’ll get the diamond ring version.

    Many thanks to -=FRG=- CrazyEddie for finding this one.

  15. I’m at the 98% totality line. I had some issues with an old injury and held off getting my annual physical , but it is clearing up and the demand for commercial pilots is insane here in NE Oregon. Motels are going for $600
    a night for ones that do not come with cockroaches. I’ve been approached to rent out my Back driveway.. Local city is not amused..(they have their own RV park…) It is worse in Baker city at the 100% line..
    Anyway there are going to be CLOUDS of Aircraft. I flew in the eclipse in
    ’78 in Rchland, Washington,and that was insane..Now add the fact that August 21 is in the heart of fire season (if it ever warms up and dries out) the ingredients for a Mike Charlie Foxtrot is there…
    With the last one it was divine providence that no one got hurt…

    • It was pretty insane back in 2015 here in the Faroes(100% line), probably not as insane as it will be at your place though, but that is just a matter of scale really, I was damn near ready to push people into the sea. (Was hillarious on some level thouh, that most of them clumped together in cloudy locations, while we were in the yard with clear blue skies)

  16. According to a new paper from the Berkeley Seismo Lab, there JUST may be something to the old lore of “earthquake weather”….but not on a “weather” basis, (gee, it’s hot and still today…feels like earthquake weather) but rather on a seasonal timescale.
    As most know, we have two seasons here in California…our “wet” season which generally runs from late October through April, and our “dry” season with minimal/no precip from mid Spring through mid-Fall. Seems the sheer weight of California’s Winter precip/accumulated snowpack can depress the Sierra around 1/2″ in “normal” rain-years. As we progress into Summer and snow and snowmelt/runoff eases, there is an elastic rebound effect that can slightly alter stress patterns over California and Nevada.
    For me, being a San Francisco native-son, I’ve felt hundreds of shocks in my lifetime…and I was always curious why there seemed to be an uptick in local shocks around April and again in October…which up to this point I always considered purely coincidence (the April 1906 Great Earthquake and the October 1989 Loma Prieta jolts notwithstanding). But this new report does make me want to reconsider that there may have been something to my “imagination” (think Spidey-senses) all along?
    And the paper itself:

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