The VC Bar

Welcome to the Volcano Café bar, a place for all things on or off topic and inane ramblings. There has been a need of late to find a place better suited to various theories, long comments and enthusiasm. This page will be less moderated than the main article pages and cleared out every month (this may change depending on use).

Have fun and don’t forget to tip the barman 😉

2,679 thoughts on “The VC Bar

  1. https://www.youtube.com/watch?v=zNPnBaO7tYg

    Amazing video of Tristan Da Chuna eruption 1961. That island is the last gasp, of a dying hotspot, that now erupts viscous evolved highly alkaline magmas. Good video on the 1961 growing lava dome. The volcanologists even climbed the growing trachyte coluee in this video, with glow visible between the lava blocks. Tristan maybe a typical phase when an oceanic plume dies off. The Tristan hotspot track have been decreased hugely in output over the 100 million years, when you look at the seafloor track. Soon this hotspot will be dead

    • Similar viscosity is produced by Santorinis Nea Kamenis mobile dome lavas.

      Another eruption happened offshore 2004 in Tristan Da Chuna where grey green phonolitic pumice suddenly boiled up everywhere in the coast

  2. https://www.rtve.es/alacarta/videos/documentales-color/erupcion-del-teneguia-diario-volcan/2898715/

    50 min of the 1971 Teneguia eruption in the Canaries. Beautyful alkaline olivine basalt with xenoliths.
    The sillica content is low below 50% but the viscosity is a bit higher than example Kilauea, because the temperature is quite low of most alkaline basalts. Canaries Hotspot volcanoes are perhaps the oldest active on the planet. Teide been alive for 20 million years, but its sitting on a seafloor thats hardly moving, but the output in Canaries is very low, and the magma production is small, as very alkaline as their magmas are.
    The 2011 – 2012 El Heirro eruption produced insanely strange evolved alkaline magmas, that mixed with both felsic and mafic alkaline melts.

  3. The calm before the storm, there doesnt seem to be any imminent eruption at our favorite volcanoes. Really this is probably a very normal situation, we just had a decade of exceptional events. Remember that Holuhraun was the biggest lava flow in Iceland since 1784, its rather unlikely that there will actually be another even bigger flow so soon. Same at Kilauea, its frequently active but before 2018 the last flow that probably would have impressed us was when Pu’u O’o was fountaining, and the previous really high volume flow was in 1960 and 1984 at Mauna Loa There were also almost yearly VEI 4s for a while, and 2011 saw what was nearly a dual VEI 5.
    Perhaps we need to have a really in depth and serious look at the places in Iceland that can still go big, the uncollapsed volcanoes, the unrifted rifts, the recurrence times set to tick over. Theres historically been a lot of wild speculation, all fascinating to look at, read, ponder the outcome, but today the site is different, and perhaps those old articles are not quite at the standard we hold for new content today. Rather than a guess, we need a list.

    Being that I am quite partial to effusive volcanism, there are two volcanoes which I think are currently primed for a flood basal and may do so in the near future, neither of which I have seen discussed here very much on the subject in a serious manner. I also have a 3rd candidate which I think is maybe the most interesting of them all, but which I need more information, its location might be familiar to long time readers.

      • Yes, we need a list of all the rifts that are known to produce big eruptions (over 1 km3) in Iceland, their last eruption of such size, and the repose period

    • Its probably not big enough to do a flood basalt draining event, Erta Ale is only 600 meters high and theres no large a’a flows on it anywhere to suggest it has done so before. Theres an a’a shield at the north end of the range, alu dalafilla, but its made from many smallish eruptions, the last in 2008 but probably there have been more in the last century that werent observed well or attributed to other volcanoes.
      Alayta volcano to its south is though a proper flood basalt volcano, a massive a’a shield, its sort of the Bardarbunga of Afar. It had a big eruption in 1907, probably a bit under 1 km3 in volume, so pretty comparable to Holuhraun and fissure 8.

      The Hekla of Afar is Dubbi, the volcano that breaks all the rules of volcanology. Really the similarity is striking.

  4. I’m not advertising websites I promise!
    Saw this study on mantle plumes and found it quite interesting – they didn’t seem to think Yellowstone among others classified as a hotspot.
    Have to say I don’t see many other reasonable explanations for the East Australia plume nor for that matter Reunion – although others like Galapagos and Cameroon there are alternate explanations.
    http://www.mantleplumes.org/PlumeProbability.html

    • Actually, east australia hotspot is possibly from uplift and decompression, and a bit of extension. The field is on thin crust, its only 20 km thick at that location, same for the also active Undara field in Queensland, not all of Australia is ancient cratonic crust.

      Galapagos is certainly a plume, its magma production is comparable to Iceland, and not a lot less than Hawaii, the lavas of all 3 are nearly identical tholeiite plume basalt.

      Reunion is also a plume, same as Afar and Virunga.

      • Hawaii is indeed a ridicolusly powerful Hotspot melting through a 100 kilometers thick oceanic litosphere like a glowing knife through butter.

        My question is for you
        Swedens – Finlands cratonic litosphere ( thickest in the world! ) are around 270 to 340 km thick. Thats ”only” little more than twice to 3 times as thick as Hawaiis oceanic litosphere.

        What woud happen if the Hawaiian Hotspot was placed under the behemoth of the superthick Baltic Craton Shield?

        I expect northen Europe woud get a huge litosphere dome boulge, but woud it break through 300 kilometers of rock?

      • Hawaii under Sweden perhaps: the worlds most blowtorch hotspot VS the superthick superboring sweden craton… perhaps it owud happen when all the magma woud pool under the craton?

      • Fantastic video on Mantle Plumes: excellent graphics and information
        PS Super Earths with their deep mantles must be a paradise for these plumes.
        Now back to Hawaii Hotspot placed under Sweden, I asked albert before, but perhaps it woud break through like Siberian Traps?

      • Sweden and Finland are so thick that the astenosphere is just a thin layer here, just enough to allow us to glide east, but much less astenosphere here than under an oceanic litosphere or near a spreading ridge. Cratons haves deep roots that contains diamonds 💎
        If Kimberlites can blast through a craton,

        Then Hawaii Hotspot placed under Sweden .. woud certainly do something! I imagines a huge magma pool at the base of the litosphere, if + 300 km is enough for 1600 C decompression of the hot plume melting. We place the Hawaii plume in the Baltic Sea

        • Hmmm placing Hawaiis Hotspot under Baltic Sea craton woud result in something perhaps bigger than Siberian Traps.. magma pools under litosphere as you explained.

          Cheers from your friend Naha#Svensson

        • Most, if not all very active Hotspots occurs under oceanic litospheres in the deep seas. Because souch litosphere is much thinner and easier to melt through than a continetal one.

          Sweden is extremely thick and certainly Finland is a real craton behemoth hundreds of kilometers thick! Basicaly almost as thick as the distance to ISS

          Its not certain that Hawaii woud be able to melt through there. But perhaps dome it.

          • It would just divert around it and erupt at the edge, thats what happened under India when it overrode the Reunion hotspot. I dont think any of the flood basalts have actually erupted right through a craton, they go in the gaps, which is why a lot lead to rifting.

            That being said, Hawaii as it is right now being very hot and focussed, possibly could puncture a craton if it was too wide to flow around. But it will be about 70-100 million years before continental crust of either Australia or Zealandia overrides that location, assuming the Novopangea model. If the Pangea Ultima model proves correct it will never be overridden in this supercontinent cycle and possibly wont live that long anyway.

          • Finland is a true behemoth even for like a Hawaii Blowtorch
            Finland maybe 330 kilometers thick at least 270 to 290 km, near Moscow its more than 300 kilometers thick on many maps!

          • Siberian Traps FB flows contains some diamonds I think
            Signs it penetrated a very very thick litopshere, It was very thick in the permian too, thats geologicaly acually very recent. knowing earth is almost 5 billion years old. Supercontinent Flood Basalts, does happens in the weaker seams between the cratons. The Earth is quite massive and still contains tremedous ammounts of internal heat, so a new FB province will happen someday, perhaps in African Rift?

    • Yellowstone, Reunion and Galapagos fit well what you would expect for a mantle plume, a flood basalt created by the plume head followed by a trail of volcanoes created by the plume tail… The trail of Reunion is a bit weird though.

      All the likely plumes are located above the LLSVPs, I guess that could mean that they are indeed strongly linked but I also have to wonder if tomography is actually imaging the LLSVPs instead of the actual narrow plume tails so that it fails to find those plumes outside broader anomalies.

      I don’t see any other way to way something like Yellowstone, or Galapagos, but maybe there is a good explanation I’m not seeing.

      • Plumes become relatively narrow after their flood basalts. For example considering that Mauna Loa volcano will leave its shield stage not too long in the future and that Loihi might enter it also around that time, then the spacing between shield stage volcanoes is about 70 km (the distance Loihi-Mauna Loa), could that be how wide the Hawaii plume is? Galapagos is perhaps just a bit bigger, the spacing between shield volcanoes is about 100 km. While for Samoa it seems to be 70 km like Hawaii. Yellowstone Caldera is also about that size or smaller.

        If a plume is 70 km across can tomography detect it? Don’t what the resolution of those studies is, but I am curious about it.

        • I also remember that Mauna Loa entered shield-stage about the time Kohala left it, and their distance is also about 70 km. So the strong part of the plume (or the plume altogether) might have a ~70 km diameter.

        • The distance between Hawai’ian volcanoes is quite constant. Regardless which direction: it is valid both along the movement of the plate and perpendicular to it. (Given the spacing, there should be another volcano in Pahala ..)

          I don’t think it is the width of the plume, it is the resilience of the oceanic crust. If you take some meltable but not flammable material, and slowly pull a candle along underneath, it will make a series of holes – not a uniform track (assuming the material is not too thick). It is like the inverse of the penitentes which wrote about a while ago. The heat gets funneled towards the nearest hole. when that is too far away, it will make a new hole.

          • Pahala swarm is maybe too deep and too close to the Big Island to actually erupt where it is, so to surface it must merge with an existing volcano, which is looking to be Kilauea. There is a gap before Kohala where the 70 km space doesnt hold and Kohala is a very big volcano possiby bigger than Mauna Loa. I have read that the rate of growth for Kilauea in the last 1000 years is actually already even higher than the long term of many of its predecessors, so it could have been getting this boost for a long time.

            Speaking of which, both Kilauea and Pahala have been pretty active this past few days, there was also an 8 km deep quake right next to Pu’u O’o and within the rift zone.

          • That isnt in contradiction to what I said.
            Pahala swarm is still underneath the crust, its not a hole, it seems there could have been a volcano where Pahala is now but it missed its chance.

            Kilauea today has an absurdly high activity for what it actually should be when you plot its age and current volume. Its something like a factor of 3 times higher than it should be. Mauna Loa is still holding on to the plume somewhat so its not just that, theres something extra driving Kilauea to its current extremes.

          • I was referring to the area where the volcanoes are in their shield stage, which seems to be very narrow, around 50 km across. Practically all the volume erupted from Hawaii comes from this tiny space which makes me think it could represent the plume extent. For example Mauna Loa was the only volcano in Hawaii erupting at a high rate between 330,000 and 100,000 years ago showing that it was perhaps was out of reach for the others, who are only 35 km away…

          • It certainly means that it contained the dominant conduit, and that magma from much of the plume are could reach it. Once a flow pattern is established, heat also gets funnelled to this area so this benefits the melt fraction. This area can be a bit smaller than the deep plume (which I think typically is considered to be 100 km across). In the early stage of a plume, the plume head can be enormous. But that is not maintained for long. the plume head itself limits the plume strength because it reduces the temperature gradient long the plume, and this provides the buoyant force.

          • The initial plume head can indeed be gigantic, when Hawaii first formed it coud have boasted a plume head as wide as the moon!
            This formed a Major oceanic flood basalt province thats now subducted. Was the initial Hawaiian LIP acossiated with any rapid global warming?

            Triassic – Cretaceous had many superplume events and LIPs as well as hyperactive new oceanic spreading ridges ( atlantic and indian ocean) was spreading like crazy back then, so much that the oceans chemistry changed. The whole Meozoic was warm and humid with clear warm calcite seas, and high volcanic CO2 that sometimes was in the many 1000 s of ppm.

            Today Earth is forming less seafloor and haves less mantle plume action because we haves many tectonic plate boundaries now that vents the heat as well as no insulating supercontinent. Thats the reason for the Cenozoic Ice Age… less volcanic CO2.

            But now humans are realising gigantic ammounts of CO2 turning the world back to cretaceous, if we not stop it

          • Strangely the Pacific Ridge have been superfast for 100 s of millions of years wirthout tiring at all. Atlantic have slowed down alot since cretaceous. The pacific ridge is getting closer to the continents and maybe overidden soon by americas? But the South Pacific Ridge is still far from the continent. The Pacific wont last forever

          • On some of the fast oceanic spreading axis, you can find something that looks like miniatyre seamount chains, are these tiny tiny shallow hotspots? that cannot melt through a avarge thick litopshere?
            These miniatyre plumes can only surface near thin thin newborn oceanic litosphere? East Pacific Ridge haves many of these little seamount chains, that maybe tiny mantle plumes that needs a very thin litopshere to melt through.

          • They are small magma chambers fed from the rift, and carried sideways by the moving plate.

      • Thats the inner plume stem and central plume head top where its 1600 C thats perhaps 70 km wide. The crust under Big Island and South Hawaii maybe competely molten

        But Hawaiis plume is quite large, hotter than avarge upper mantle temperatures extends for a round arera more than 600 kilometers out. The plume head is also dragged a bit with the litosphere above, forming a tail towards the older Islands.

        Hawaii Hotspot domes the seafloor in a boulge more than 1000 km wide ”Hawaii Swell”

        But most of melting activity goes into one or two dominant Hotspot volcanoes in Hawaii ( that suggest a smaller and very very intense Hotspot head )

        • Yes, the point is that practically all the volume is erupted from the 70 km circle of shield-stage volcanoes, and there is usually drastic changes in magma chemistry and supply when a volcano enters or leaves that circle. The material from the plume must spread around the mantle after hitting the lithosphere so that may generate the wider area of weak rejuvenated volcanism and partially molten mantle.

        • Yes, Hawaii is tremedously focused into a narrow space basicaly one 100 000 km3 edifice that grows up in just a few 100 thousands of years. The speed of the plate movement and the strenght of the Hotspot determine the size of the volcanoes produced on the oceanic litosphere.

          At current its a major sourge in Hawaiis geolgical output since Maui Nui. These volcanoes are so big.

          Mauna Loa will go alkaline soon right? 1984 was quite cool but still very fluid movable and Thoelitic. When will Mauna Loa leave postshield? Its been 33 eruptions since 1840 from Mauna Loa

          • Mauna Kea left shield stage at about 330 ka, when its eruption rate dropped by an order of magnitude. Since the plate is moving at about 7 cm/year, then the shield to postshield transition (edge of the plume?) must have advanced ~23 km, that puts it at the current position of Mauna Loa’s summit more or less. So Mauna Loa should be leaving its shield any time now.

            What is interesting is that Mauna Loa still can get almost the full supply of the hotspot. It depends on the state of the rifts, Kilauea has the most efficient rift of Hawaii, the East Rift, which is very long and unbuttresed. But when its activity is very low (due to the internal cycles of Kilauea) Mauna Loa takes over completely. Last time this happened was the 1850-1880 period, when there was 0 east rift activity at Kilauea and very little volume gain, Mauna Loa was throwing one huge eruption after another. The longest and most voluminous eruptions of Mauna Loa happened back then: 1855 (one of the longest ones, at 10 months if I remember right), 1859 (very long and the 3rd or 4th most voluminous), 1868 (volume not very well known but very large, and basically resulted in the devastation of the southern part the island with a M8 earthquake and associated tsunami), 1871-77 (longest and most voluminous, unless 1868 was bigger), 1877 (2nd or 3rd most voluminous, something like 0.5 km³) and 1880 (9 months long and nearly destroys Hilo). So Mauna Loa doesn’t show any signs of weakening, the only thing that weakens is the east rift of Kilauea, like in the past several decades. It’s a very sharp transition probably, the demise of a Hawaiian volcano that being, Mauna Loa won’t lose its strength until it loses access to the hotspot, which should be happening very soon, but until then… it can still be the dominant volcano whenever Kilauea is burnt up.

          • Probably still got another few tens of thousands of years in it, and the change is very gradual too, Hualalai is still partly tholeiitic and its nearly as old as Kohala.

            I guess if you look at it, Mauna Loa is about an order of magnitude more active than Hualalai, and (generally) an order of magnitude less active than Kilauea, but the fact it sometimes takes dominance of the plume from Kilauea shows its probably still not that close.
            Hualalai is about as productive as Katla, by the way, even postshield Hawaiian volcanoes are nothing to scoff at.

          • Apparently Hualalai also abandoned shield around 330 ka, so either the plume is not circular or there are more factors involved, so I guess it’s not that simple and Mauna Loa may still have some time left (or not).

          • I also cant see any evidence Kilaueas east rift was weakening over the last decades, it seems more open and active now than any other time since the 18th century, and the supply is still very high. There was magma accumulation east of JOKA station early this year, but no quakes, so it seems there isnt likely to be any sort of long obvious intrusion, its just filling in the entire system until it breaks somewhere it seems. Probably though the tensile strength of the rift isnt high, so it might break quite soon but with little fireworks, it might just happen suddenly after a few hours of quakes for all we know.

            Unless what you mean by ‘weakening’ is that magma has less (probably none) obstruction to flow into the rift, and not weakening flow rate, in which case that is indeed the case.

          • Another way to look at it is by looking at how much distance Kohala travelled during its shield stage. Transitional lavas of Kohala are 1.15 million years old and show its entrance into the main growth phase, while it started to submerge under water 500-430 thousand years ago which was its waning. So it travelled 50-45 km over the plume during its shield stage. This is a better estimate maybe for how wide the area that provides most of the magma supplied to the volcanoes is. It would have a diameter of about 50 km only.

          • I meant to say “the only thing that weakens it”, but missed the it. That Mauna Loa erupts less because of the East Rift of Kilauea and that when it is inactive Mauna Loa grows at a rate close to the long-term growth of Hawaii Island.

          • In the 1800 s and early 1900 s since modern historical obervations began until 1950, Mauna Loa was very active erupting 33 times between 1840 – 1984, thats a frequency with large lava flows, that quite no other volcanoes can compete with, only Iceland comes close in frequency of “larger volumes regulary”. Mauna Loa apparently had a very robust supply before 1950 s, then Kilauea became dominant over the plume, the two volcanoes often shift between dominance. Kilauea huge mass is showing that she will soon be dominant over the hotspot.

            Earlier in the Late Pleistocene Mauna Loa woud have been hyperactive with 100 s of years long shield eruptions, the longest holocene shield building episode at Mauna Loa lasted perhaps 1100 years according to some USGS data. In early holocene Mauna Loa was also very quiet for a while 7000 years ago.

      • Hawaii is a very intense and focused Hotspot into a local arera. Most of the output of the Hawaii Hotspot goes into one dominant volcano when its over the Hotspot, these volcanoes can grow go well over 100 000 km3!!!. This suggest the Hotspot is very focused and localized and alot goes into a small arera. Hawaii is a focused blowtorch that Burns the hell out of a small arera.

        Iceland and Galapagos and Afar seems more spread out feeding many active volcanoes, just not one that grows into a deep sea behemoth …

        The Azores Hotspot maybe larger than Hawaii BUT not anywhere near as close as hot or intense that Hawaii is
        Its like comparsion of a large fire and a intense welding torch

        • The large Azores plateau is probaly the inprint of the ”Azores plume” but its a plume thats now rapidly waning. Most of the Azorian Islands sits on leaky transform faults and gets a minimal supply from these.

          The supply to Kilauea exceeds the supply of all the 9 Azores Islands combined many times.

          But on the other hand, Azores haves their beauty, and a very pleasant oceanic subtropical climate.

          Azores most holocene productivity went into the Pico basaltic stratovolcano. Picos subarieal cone part is just a few thousands years old, so it have erupted constantly in holocene, with very slow basaltic pahoehoe oozing for 100 s 1000 s of years nonstop. Pico Island was for a long time ”Ligthhouse of the Atlantic”

  5. VC friendly size perhaps of this image?
    Indeed Azores most holocene productivity went into the Pico basaltic stratovolcano. Picos subarieal cone part is just a few thousands years old, so it have erupted constantly in holocene, with very slow basaltic pahoehoe oozing for 100 s 1000 s of years nonstop. Pico Island was for a long time ”Ligthhouse of the Atlantic” that was unseen by humans back then. I myself visited Picos summit in summer 2019, it was a magical sight, with the deep blue atlantic and popcorn cumulus everywhere as far as the eye can see. Pico is one of the tallest and youngest stratovolcanoes on the planet, rising from the deep sea. The flanks of Pico are covered in
    “entrail type pahoehoe everywhere” suggesting tubes and lava lakes in the summit. The Azores Hotspot is with certainly housed under Pico – Faial islands.

    • A part of the crater wall haves collapsed and slide down… revealing the round caldera lava layer fill cake

    • Yes thats was an awsome experience to see with you, Im his brother and yes it was a mindblowing sight to climb it.

      • Look at Picos size and how fast it grew, a normal spreading ridge location simply cannot do that thing.. There is a plume below there, perhaps dying. The Azores Plateau a kind of small LIP is the “handprint of the plume” Where and when the Azores plume came into existence is not known

        • I doubt Pico is entirely formed in the holocene, maybe resurfaced but for such a huge event to happen yet be so inactive now seems unlikely. You do get random big eruptions at old plume volcanoes like on Lanzarote, but those tend to be flood basalt eruptions not long lived events.

          If I was to guess Pico has been growing steadily since about 50,000 years ago or so, but maybe the rising sea level in the early Holocene caused a bit more pressure and it erupted more often, hence the young surface.

        • Chad Picos older parts are
          50 000 years or so, but pretty much all of the main cone that sticks above the water is holocene. Picos main cone is competely covered in entrail pahoehoe lavas everywhere. From the base of the cone to the summit is all pahoehoe. It erupted slowly under very long timespanns. Infact its almost built like an oversized pahoehoe mound. Uniform Entrail looking pahoehoe drap the entire Grand cone if you climbs it, I never seen any other stratovolcano thats like that!

          The lower flank of Pico does contain many later monogentic cinder cones and Aa flows. Been some cinder cones and Aa flows in human historical times.

          Being very productive under a short time, it was thought that Pico had a large shallow magma chamber, but none have ever been found under the Island. Picos magma apparently came deeply from the mantle, unevolved fluid alkaline basalt. It formed a stratovolcano because it erupted fluid magma very slowly, more slowly than Hawaii

        • Look at Google Earth, look at Picos main cone, mostly pahoehoe if not all of it, with some later Aa fissures.

          The Northen side of the cone have collapsed a bit, sliding down taking with the northen side of the main caldera wall

          Ligthhouse of the Atlantic for 100 s of years if not thousands earlier in the holocene

          • It still doesnt mean the entire cone is Holocene, just that its surface was all covered over, same as in Hawaii where pretty much all of the southern half is surfaced by Holocene lava (and all of Kilauea) but we know its obviously older.
            It is weird that Pico is so steep for erupting the same way as shield volcanoes do though, especially with the historical eruptions being pretty normal basalt cones that behave the same as anywhere else. There doesnt seem to be a lot of information on its eruptive history either, only the historical eruptions are listed on GVP so I dont think any study has actually determined when the last summit overflows ended.

          • Ropey Lavas at summit are old enough to look like “odinary grey non volcanic rock” basicaly the glass and brittle carparace been chipped away. Soooo summit lavas are likley a few 1000 years old

        • Azores is the ideal climate for you: extremely pleasant oceanic subtropical. Very famous for its special climate conditions thats very mild and coozy, perhaps mild tepid.

          Vinter around daily 17 to 19 C.

          Summer its around 22 to 24.

          A similar climate is Northenmost Northen New Zeeland. This unique climate exist only at Oceanic Locations at latitudes in the lat 30 s. Lat 29 to 39 gives this climate in an oceanic small Island enviroment. Azores are pleasant, never hot, never cold

      • I’m not convinced there is a plume at any of the west african trails/atlantic trails. We have to remember that continents broke apart here, there are lots of faults and areas of weakness especially perpendicular to the MAR.

        The ages of islands in the Canaries are not consistent with a plume either (although maybe the head & tail model) and are more compatible with a spreading rift.

        Finally, I would also question whether or not a triple (or quadruple) junction can birth a plume!

        • Canaries sits on very old thick oceanic litosphere thats hardly moving at all

          The Hotspot is very weak been sitting in the same spot for 20 million years and hardly made Islands thats only a bit larger than the Azores

          Hawaii Island is more than 20 times younger than than Canaries.

          Hotspot under Canaries, its the only way to form deep sea Islands in an oceanic enviroment, ridges and faults does not generaly form larger oceanic Islands

  6. We have a little swarm ongoing at Kilauea. Counted around 50 since 09:00 UTC, most of them less than magnitude 2. Did have one 3.3 shallow quake.

    2020-11-30 12:06:07 3.3 0.9

    Mac

    • Strange swarms, reminds me somewhat of the March 16 event.

      The M 3 is followed by a VLP earthquake with the ground moving down, up and down over 2-3 minutes. And there is also noticeable rapid deflation of the volcano after the M3 followed by ongoing re-inflation visible in the tiltmeter.

      Very similar to the March 16 event, only that back then it produced rapid inflation instead of deflation.

      A weak long-period swarm a few hours earlier:

      The main sequence of intense ground cracking, the M3 and the VLP (although this last can’t be appreciated in the spectrogram):

  7. Question – probably for Albert (as I think he’s the resident space expert?) – I saw someone ask how long it would take to drive to space – I immediately thought of rovers on mars going up olympus mons (I gather that’s 600km wide, and the rovers go at 3m/min (0.18km/hr). But then I realised that the very very thin atmosphere would still covert he summit of olympus mons.
    Does anyone know the altitude on mars where the air pressure there is the same as at 100km on earth (which apparently counts as ‘space’ because a plane flying fast enough to climb at that air pressure would be going fast enough to orbit rather than ‘fly’). And thinking about it – if that’s the definition – is the altitude lower because the orbital mechanics of mars are different to earths’ and so what would be the martian air pressure when you got to the speed of ‘orbiting’ in a plane. And what altitude would that be at? And so does olympus mons actually go up into ‘space’ ?

    • Olympus Mons summit haves extremely thin CO2 air pressure, and rises above the dust storms.
      The pressure at Olympus Mons summit is perhaps similar to the air pressure at 60 almost kilometers on Earth. But despite that… water ice clouds still drift over Olympus Mons summit and dust do slowly get desposited in the caldera. Mars lower gravity makes it thin atmosphere more extended than Earths. Spacesuit defenetivly, but not space even at OLM s summit.

      Albert can perhaps give the more fancy information

    • The answer may not be what you expect. Let’s take 80 km rather that 100, as that is the top of the mesosphere. Above that you get the ionosphere and there the pressure is different. At 80 km the pressure is a few microbar. The same pressure on Mars is reached at an altitude of 100 km. The pressure at 80 km is a bit higher on Mars than it is on Earth.

    • Albert whats the pressure at Olympus Mons summit equal in earths atmosphere? Is it similar to 60 kilometers at Earth?

          • hmm I meant space – not orbit – and I guess you would have to be driving pretty fast up olympus mons to end up in orbit 🙂

          • A railgun on the slope of Olympus Mons might manage that! Could be a cheap way of putting things in orbit around Mars without needing rockets. most of the rocket fuel is used to accelerate the fuel itself. If you can leave the fuel at home, it would make launching much more efficient.

      • Hi Albert: imagine a scenario without any mineral dust at all in Mars Co2 atmosphere.

        Woud the marsian noon skies be black?

        Mars surface pressure is only 1/100 th of earths surface pressure so there is 100 times less light raylenght scattering.

        Earths Noon skies in the tropics can be very deep blue at 1 bar. At 16 kilometers altitude its almost black for earths skies

        Without the dust im soure mars woud have black dayskies.

    • The atmospheric pressure at the top of Olympus Mons is 72 pascals, thats 12% of mars summit pressure, so the pressures is very low, but not like the karman line.

      • I think something got mixed up here. You copy wikipedia but with ‘mars mean surface’ replaced with ‘mars summit’. The wikipedia number is overstated, as Mars surface pressure varies by a factor of 2 during the mars year. There is one other site which gives the pressure but they are off by 50% because they get the height of O.M. wrong. It is not 27 km – that is the height above base. O.M. is ‘only’ 22 km above mars mean surface level.

  8. Around 120 quakes this morning on the Big Island around the caldera and the rift. Most are less than 1 in Magnitude, but we did have a 3.1.

    2020-12-03 03:59:20 3.1 1.8

    • A very sad end to the telescope. It is also a lesson for a funding regime where it is possible to obtain funding for a world-class telescope, but not for sufficient maintenance. Maintenance is expensive, but not doing it can be disastrous. Funding agencies invariably prefer new opportunities over maintaining what they have. The collapse is a direct consequence of being unable to pay for replacement cables.

    • If that happened it woud be like Nordic Ragnarrök.. the final everlasting killer winter slowly descends over the Earth.. and the sun grows smaller every year as the kicked out Earth races away. As the video suggest only geothermal vent deep sea animals woud surivive that. Along the fast spreading ocean ridges the sea will be liquid under the ice.
      But is earths internal heat flow large enough to maintain a global ocean under the ice.. if we got kicked out from the solar system?

  9. Posting this here as it’s one of the best volcano videos i’ve seen. Real in-depth and clear explanations of the driving forces behind Mt. Paektu. https://www.youtube.com/watch?v=3C2HVOB-g5s
    As someone with a background in chemistry and basically just picking up what I know about volcanoes and geology in general as I go – this was extremely helpful.

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