Brimstone over Iwo Jima!

Joe Rosenthals photograph from 23 February 1945 is one of the most iconic images ever taken. If the camera would be pointed at the same spot today at the same elevation we would only see rock since the place have been magmatically uplifted 17 meters.

Joe Rosenthals photograph from 23 February 1945 is one of the most iconic images ever taken. If the camera would be pointed at the same spot today at the same elevation we would only see rock since the place have been magmatically uplifted 17 meters.

68 years ago US troops stormed the beaches of Iwo Jima’s Mount Suribachi, the site where they landed is now a full 17 meters above the ocean surface.

I have often written about caldera forming eruption being cyclic, and that as the magmatic system starts to evolve after the cataclysmic event it starts with small eruptions ever so slowly getting larger as the magma chamber grows in size with each magmatic influx. This is though only true for some volcanoes like Grimsvötn or Krakatau. There is a class of volcanoes that behaves radically different.

These volcanoes are the resurgent domes and Iwo Jima is one of them. Iwo Jima is not one of the easiest volcanoes to write about since there is not a whole lot of research that have been done on it, at least not a lot that has been released to the public. It has after all been a military facility for 75 years, and during those years it was even for a time a nuclear strategic air bombardment base.

Resurgent domes form as a magma is filling under the rubble of the cataclysmic caldera forming event. The rubble first get soldered together as magma oozes up through old feeder channels, as the magma filled the area between the rubble it was in the case of Iwo Jima quenched and in the end a hard but flexible layer 2 km thick had formed.

By then the magma started to accumulate under the current Island of Iwo Jima slowly pushing it up from the bottom of the caldera floor until it breached the surface. When exactly that happened we do not know, but if the rate of uplift have been constant it happened roughly 680 years ago. After that the Island grew into today’s height of roughly 170 meters.

Iwo Jima Is situated inside a nine kilometer wide caldera, at 21 kilometers it takes up about one third of the original size before the caldera forming event. Iwo Jima is surprisingly benign for being such a massively inflating volcano. There are a number of reasons for this.

The first reason is that even though inflation is changing between 10 centimeters to 80 centimeters per year it is fairly constant. And by that the roof of the magma chamber has time to move without cracking. If you bend rock over a long time it is surprisingly bendable, especially since the rocks over the chamber are rather hot making them very ductile. If the rate of magmatic influx was lower the roof would get less heat and thusly becoming more brittle, and during a sudden magmatic intrusion it would crack. If the rate of influx was higher it would in the end just melt through the roof.

Classical phreatic detonations photographed at Iwo Jima.

Classical phreatic detonations photographed at Iwo Jima.

The roof is though not perfect, there are a crack in it so that gasses can pass out from the volcano, and it is from there the name comes, Sulphuric Island. This degassing lowers the volatility of the magma giving additional time for the swelling before a larger eruption would occur. There is just not enough force for a lot of magma to punch through.

Now most say that Iwo Jimo erupts quite often, but in reality it erupts less frequently then commonly believed. Instead most of the eruptions are phreatic detonations, which even though they are spectacular, are not true eruptions since no new lava is ejected out of a vent. Instead it is just rock being blasted as water comes into contact with a highly warmed piece of rock (or even magma) at depth causing a hydrothermal explosion.

Inevitably though the roof will burst the same as any overinflated balloon would do, when that will happen is anyone’s guess. In theory you could try to measure the quality of the roof over the magma chamber to decide how durable it would be according to a number of criteria. Sadly enough it is impractical onto the boarder of impossible since it is not a homogenous piece of rock.

And that is the problem with your average resurgent dome. It will go about pushing up the bottom of the old caldera floor, having some minor activity like Iwo Jima with phreatic detonations, some small eruption with a little lava, active fumaroles and hydrothermal fields. And it will be fairly gaseous, all right then, stinky is the word. And in all that benign activity it is hard to remember that the island is doomed to one day blow up and we will not know if it will happen tomorrow, or thousands of years into the future. The most likely though is that Iwo Jima will not survive for that much longer, probably not more than a few hundred years, even before it has grown to the same size as the old volcano. And the reason for that is that it has a very shallow magma chamber. If we compare it to other known resurgent domes the chamber is just too shallow to be able to take the strain for much longer.


122 thoughts on “Brimstone over Iwo Jima!

  1. Caldera structures… much more prevalent than one would think.

    I am beginning to think that the only difference in whether a system goes caldera, is the balancing act on how fast magma enters the system, and the strength of the overlying roof.

    • Heres this “thing” that I found while putzing around on Google Earth. It’s ellipsoidal, and has a central uplift/dome like structure. 38.287716°N 128.122839°E. It’s likely either some sort of a collapse structure, or an impact site. Well, just because it appears that way, that don’t make it so. I can’t even get a name for it.

      • After looking at your “thing”, I found a cool “thing”. Panning left you will see a river between the cities of Yonan and Kaesong. Follow the river up and just below the city of North Hwanghae, is the outline of an old man’s head. Dear Leader?

            • Well here is the most detailed geology report I could find. This is an interesting book for anyone into geology and the history of warfare.
              Scroll down to the article about Clandestine Tunnel #4 in the Korean Punchbowl.
              If it’s a caldera then it is very, very old. There are volcanoes but not in the immediate area although the geology suggests at one time this area was volcanic.
              My take on it is that there is a hard “dome” of intrusive granite that may have been overlaid with sedimentary rocks or was covered by softer metamorphic rock. As the top layers wore away and were eroded weather particularly running water so a disc type shape appeared . The water would follow faults and there is mention of many faults within the depression. The fact that the intrusion was dome shaped would account for a dome which could be construed as a resurgent dome within a caldera on initial observation.
              Water would naturally erode from the crest of the dome downwards removing softer material than the granite. This erosion would enhance the appearance of an elliptical or circular shaped crater.
              Like Lurking I too admit to being baffled and to being a mere amateur and ruminator 🙂 But it is a nice little mystery and the feature is by no means small. I wonder if there are more of the same and like Lurking wonder if these features have a special name?
              Come on professionals surely you can enlighten us can’t you? 😀 😀

            • Mail for Lurking… 🙂

              Edit: That papper came in the worst formatting I have ever seen…

    • Oh how dreadful! My sympathy to all involved. Such brave men. They don’t deserve to die even though they accept it as part of the job. Too, Too tragic. 😦
      Never mind TG, I am sure your family are happier with you working locally.

    • Very sad. I know there are much too few a/c employed on firefighting, despite Heavy Jet conversions like B747, this likely leading to more fires having to be fought from ground level. I am however very happy you have some thing to fly, not all have such 😉

      • Don’t get me started about the P-3’s like the DC-4,6,7 they should still be on the line.
        Aero Union had 8 they went out of business due to ineptitude and politics.
        That and the Bank (BOA) won’t sell anything at a reasonable price so they sit at
        McClellan AFB in the weeds…

    • According to the news, they had to resort to deploying their shelters, but that was to no avail. Not sure what is involved in the shelter other than as a radiant shield. I’m pretty sure that there is no protection from debris and you are limited to what air you have carried with you. With the oxygen consumption rate of the fire, there may have been very little left for any critters scurrying about on the ground… including firefighters.

      R.I.P. to the crew.

        • Still a lot better than without…
          But I sure as heck would not like to be in one. I probably do not have firefighter material in me.

            • {snicker} Motivation.

              Not quite related… but a fire story none the less. One of our “Explorers” (16 year old that is a volunteer with parents signed permission.), the very same one that had pulled a knife on me in the parking lot, was on the line behind me and we were preparing to head up into the attic where the fire was. (from a lightning strike). We charged our bottles and he was having issue with his timer. I took the nozzle and headed up after the fire. I didn’t find out until later that I had literally drug him up the attic ladder as he was clinging to the hose. Found the fire, put it out, looked around for residual hotspots. Found that I was crawling around on top of a house trailer. It seems that the entire house, had been built around a house trailer. From the outside, it looked like a normal house. But in the core… house trailer. Whoever did it, did a pretty good job. The rooms melded into the structure like they were ment to be there. Internally the only way you knew you were in the trailer was that it got a bit more cramped and the walls were thinner… plus the floor had a different feel to it.

    • yeah Rick ! I too checked out the weather. We’ve seen this before and I suspect maybe some human/mechanical activity.Also the air pressure tend to make it’s mark.
      I would be looking to see a few micro quakes at least if Hekla was seriously disturbed.

  2. Thanks for the interesting post, Carl! Do I understand it right that the magma chamber is really only at 2 km depth?

    This year I convinced my family to have our summer vacation in the Eifel volcanic field. So in two days it will be Vulkanbrauerei instead of Volcanocafé and taking lava samples for Spica instead of googlefooing lava picures.
    Hopefully my mobile internet is not too crappy so I can drop in here once in a while 🙂 .

    • Yes, the thickness of the roof is only 2 km. They tried to do a drillhole, but they couldn’t because the drill bits just melted.

      Have a nice volcano vacation with Vulkanenbrauerei!

      • That’s incredibly shallow, especially for how much it has stretched.

        I’m almost a bit curious as to whether Ioto (Iwo Jima) was the cause of one of our hidden mystery eruptions that we can’t attribute the source to in the last 2000 or so years. A 9km caldera collapse event in the middle of the pacific should have been larger than Krakatoa’s largest known eruption (which created a 7km caldera)

        One thing about an eruption with such a large shallow chamber out at sea, is that you can be pretty darn sure that there won’t be much left in there when the caldera collapses and water rushes in unlike other eruptions where it’s common to see only a portion of the magma chamber erupted.

        I’d be really interested in learning more of the mechanics behind resurgent doming vs. more traditional somma formation along ring fractures. I know that these two post-caldera reformation styles aren’t necessarily mutually exclusive, but I never really considered how certain calderas seems to just re-bubble up without erupting, while most larger calderas have a tendency to go the somma route, sometimes creating multiple somma volcanoes depending on the size of the caldera itself.

        From my initial thoughts, it seems like water plays a pretty large role in whether there is a resurgent dome or whether it goes the more traditional somma route. Some of the large resurgent dome volcanoes I can think of are somewhat similar to Ioto – (Ischia, Pantelleria, etc) in that they’re island volcanoes. Then again, there are tons of island arc volcanoes such as Krakatau that avoid resurgent doming, so I would imagine that the magma chamber depth also plays a large role in whether it goes resurgent dome style as that has a big impact on how brittle the crust is above it due to heat as well as thickness.

        • On another slightly unrelated note – I’ve always thought that volcanism in and around Japan has been surprisingly mild in the last 10,000 years or so compared to how many large volcanoes exist there (not counting Kikai of course).

          If I remember correctly, there hasn’t been an eruption larger than VEI 5 in Japan in the last 6000 or so years. I suppose after the earthquakes and tsunamis, the Japanese can use a break from natural disasters.

          • Ah, I see that you allready knew about Kikai 🙂

            To be honest I would not be so sure that there has not been another VEI-5+ eruption there. After all you have loads of calderas there that are underwater ones.

            • Apparently there was a huge eruption in Japan some time around 1 million years back in the central area of the island. I forget the name of the eruption, but it would be larger than any of the other known huge Japanese eruptions in memory.

              The interesting thing is that they still can’t find the source for it, all they know is that it came from one of the central areas near the YakeDake and On-Take stratovolcanoes. I believe the ejecta was around 600square km, placing it in the low VEI-8 category. I know 1 million years ago is forever, but in geological timeperiods for large caldera systems, it’s pretty “on par” and at least shows the potential for an area I never thought could place such a large eruption.

              This was something that surprised me because most of the huge calderas in Japan are either in the north, or in the south. That doesn’t mean there aren’t huge volcanoes in central japan either, but nothing that screams large VEI-7 like Ata, Aso, Aira, Kikai, or some of the Honshu calderas which are also quite enormous.

            • 1 000 000 years is a lot. It could easily be one of todays larger volcanoes there and the entire caldera is now covered up. In that time even a moderate erupter would have eradicated all of the evidence.

          • I suppose after the earthquakes and tsunamis, the Japanese can use a break from natural disasters.

            Not to mention Ferris Bueller corrupting Godzilla.

        • I can pretty much promise that it was not Iwo Jima that stood for one of the missing eruptions. But, there are loads of calderas around it that easily could have. Just take a look at the Kikai caldera that had numeous large eruptions.

          I think one has to put in degassing as a factor. Iwo Jima is degassing heavily all the time. The Japanese soldiers where dug down into long tunnels into the mountain, and many of them suffered damages from the gases that acumulated in them and many actually died from exposure. That degassing makes the magma unusually low in volatility, ie. it does not erupt as easilly as more gas rich magmas do. That is the reason for it not having blown sky high allready.

          Most other resurgent domes seem to be having reforming magmatic chamber systems at greater depth. But, I think the big difference is if there is a ready passage for the magma to go through up to the surface. In the case of Anak Krakatau it started to erupted almost emediately after the caldera formation.

          And then you have a couple that seem to hover in the middle, with one or two vent volcanoes on the side, and with a large caldera that seems to be acting as a resurgent dome.

  3. Thanks for the post – another volcano I knew nothing about. I must start reading more!

    Very sad news about the firefighters – they are all so brave. Several firefighters were taken to hospital here in the UK today – a huge fire in a plastic recycling centre started by a Chinese lantern coming down (these things infest Britain in the summer – do other countries have them? – paper lanterns lit by a naked flame and sent up into the sky to come down on peoples gardens, thatched roofs, and so on – literally a flaming nuisance).

    Meanwhile the 140,000 people who were at Glastonbury are wending their way homeward – luckily I was driving in the opposite direction!

    • We used to have them, but an air ambulance helicopter got one in the turbine intake and then they were banned.

      • Ah hates Chinese Lanterns. One started a nasty fire out near Monterrey CA. some years ago. No homes or structures lost but, Not a fun place to work where that landed,,,
        Local store here in La Grande sold them-until the Ranger from the USFS showed up and she
        MAY BE HELD RESPONSIBLE!!!!!” The merchant removed them…
        Ranger was on that fire I mentioned..

    • Unfortunately we have those huge Chinese Lantern contexts with all those lit up fireworks hanging from them. Those are heavily fought but you can still see and hear them flying out away from the favelas where these contexts take place, A real shame!

  4. This fall Nautilus is going to the Kick Em Jenny volcano, Grenada. Let us all pray for NO hurricane!

    • Yes!!!
      I am looking forward to the Kick’Em Jenny photage. It is a very interesting volcano with it’s very short eruptions. I would love to know if it is real eruptions or just mostly phreatic detonations.
      For the newcomers. I have a huge problem with 30 minute long eruptions that are only seen on instrumentation from volcanoes that are dormant for years in between. Most often when it happens onland they are “just” phreatic detonations. But as soon as they are only instrumentally seen they for some reason end up as “eruptions”. For instance the 2011 “eruptions” of Katla and Hámarinn and the hypothetical 30 minute “eruption” of Bárdarbunga in 1996. I am always suspicious of short “eruptions” that nobody sees from volcanoes that are known to have massive week to month long eruptions otherwise. A case of “Me want eruption” sickness happening even to pros.

      And before Boris Behncke jumps all over me, I know that Etna is the exception.

    • Very good news. Please do keep us posted on this mission. I am particularly interested in Caribean volcanoes. KTJ crater is not that deep (about 200 m from memory), there is a 3d profile somewhere (see the site of university of wast indies in Trinidad)

  5. Hi

    Thank you for this article Carl. Nice uniting the historical and volcanic sides. I think there was a minor event a few weeks back (probably phreatic then)

    This a 4 subplots video of the earthquake activity under El Hierro Island for June 2013.

    The left top view show the view from the south, the right top view shows the view from the west of the island.

    The color is according to rank (event number) and is linked to date (see left side of the color bar at the bottom right)

    Terrain elevation is shown according to the right scale on the colorbar.

    Earthquake magnitude is proportional to the scale shown on one side.

    The lower left subplot is the “usual” rotating plot.

    The lower right subplot is a top view, with a lower resolution mesh instead of a surface for a better view of the earthquakes.

    The title of the top view shows (from left to right) earthquake count vs total, date span, current date.

    • Yes, it seemed to be yet another phreatic event. It seems that they are coming more often now. Since 2001 there have been a couple every year.
      Up untill 1952 there was 18cm of uplift annualy, then it dropped to just 11 cm per year, and in 2001 it rose a lot, spanning between 25 and 80 cm per year.

      DFM, I think you should do a post of one of your wonderful plots. There are now people in here who missed the excitement of Bob, and also it could be an idea since the inflation has gone up again.

      • Thanks

        80 cm seems a lot to me. There would surely be earthquakes associated….
        As for the post, I know I should. I’ll try to come up with something in the near future.

        • I jumped at that figure too, but it seems like there was that extreme at the beginning of the current increased level of uplift. Most likely there is somewhere a japanese paper on it with associated earthquakes, but alas, my japanese is not that splendid (cough).

          Looking forward to the post 🙂

      • Seems like it is working. Have you tried purging the buffer?

        Here is the last one I found.
        2013/06/30 18:39:04.16 27.6851 -18.0998 18.70 5.50 1 33.00 5.6 1.90 – 6 6 0.19 300.0 1219054 W EL PINAR.IHI

          • The browser has a memory buffer where it stores how the pages you often go to look so that they will load faster. Normally the browser check for changes and upload those to the buffered page. But sometimes that does not work. First thing to do, press F5. If that does not help, delete browsing history and cookies. If that does not work, blame Oracle, than tell us and someone more computer savvy person will help you to fix the problem (and with blaming Oracle).

            Edit: Why blaming Oracle? Well, they produce Java, and Java sprouts cookies and all other sorts of problems. They also always try to forcibly make you install a particularly useless toolbar so they can spy more effectively on you (remember, you already get their cookie monster Java machine that you can not live without).

            • That’s done the trick, Thanks Carl…
              It must be months (years?) since I cleared the history 🙂

            • It is a very usefull trick. I can even get rid of some malware and crap that has gotten into the system.

            • You have touched a sore point here carl. I spent most of today trying to get rid of a nasty search thingy called Holasearch. It came down with a Java update. I am pretty good at not allowing this kind of malware on my PC. I read carefully and make sure I either tick or untick boxes that stop these unwanted and sneaky little programs. This one managed to slip past me and the darned thing took over IE and Chrome. I won’t go into details of the hoops I had to jump through to get rid of it, but be warned about Java Updates and be very wary.

            • Oracle… yeah buddy.

              I was asked a question by one of the users (well, a manager of the users) why the printer – tray mapping occasionally gets stupid. One clerk can issue a print, and it comes out on a printer on the other side of the office. I explained that when the main office at the state capital rolls out an Oracle update, it sometimes whacks the tray mapping. I even had one office go completely inoperable due to all systems winding up with corrupted mapping. It’s simple to correct, but quite tedious when you have 17 stations and 3 separate trays per printer among those 17 stations… all with their own unique printer share fed off of the server.

              Nothing I can do can stop it, short of finding the person responsible for the updates and smashing their fingers with a hammer… but that might shorten my employment.

    • Hi Cryphia, great video,
      Sounds good too, my clunkputer is wired into the HiFi and the wall clock is rattling away…
      Hittin’ some deep rumbling bass notes…

      • OoooooooooooooooooH! That’s made me feel better 😀 Nice to watch since nobody gets hurt. I certainly wouldn’t like that in my back yard! and I agree with Schteve.. the sound is awesome. 😀

        • I particularly liked the Schtromboli segment, I only really know Schtromboli from the 3 minute webcam; this video fills in some gaps…

        • Merapi and Mayon killed people…
          The ring fault eruption did some people in at Mayon, and we all know Merapis story.

    • I actually had a tear in my eye watching Anak Krakatau. I’ve sat there one night at the same beach as they filmed from, and sailed up to the remnants of the old island. Even though Anak Krakatau was not erupting when I was there it was still magical.

      Another thing that caught my eye was the splendid photography from Mayons ring fault. Mayon still erupts from the top crater, but it is getting to high up and to narrow for the pressure, so there are increasing eruption from the ring fault around the volcano. And, I guess most people know what that entails in a country with that many inhabitants.

      • I hadn’t realized that Mayon had started to form eruptions from newly active Ring Faults. The very fact that it HAS ring faults in the first place says a lot for a volcano that hasn’t had caldera-forming eruptions in the past.

        • Yepp, it says a lot.
          I know it has one, but how new it is I do not know.
          The photography of the eruption of the flank vent at the ring fault was stunning. And that particular vent eruption surprised the local authority a lot. I think next time they will make the exclusion zone larger in regards of it.

          I think Mayon is close to having a more destructive eruption, but if it will be a blowout of the too narrow top crater, or if there will be a flank collaps (it is awfully steep), or a full blown fing fault collaps I think nobody knows, and it feels pretty horrible to even contemplate it since there are large cities very close to it.

  6. Whilst I was noseying around North Korea I found another rather large Volcano that I had not really stopped to look at in depth. This one too could go with a pretty ferocious explosion with the help of a 3 mile crater lake!
    There aren’t many volcanoes to the North West of The sea of Japan. What causes the Changbaishan volcanic region? It’s a sort of relatively small volcanic plot of land far from the North pacific Subduction zone. There are a few of these isolated volcanic areas…Dariganga Volcanic field, lesser Khingan Range, Longgang group and single volcanoes likeJingbo. This articles may explain why these wide ranging “islands” of Volcanicity occur. It’s a bit technical but I got the gist of it and for me it puts another little volcanic jigsaw piece into place.

    Click to access dyh.pdf

    • Changbaishan was supposedly the source of a VEI-7 eruption around 900 A.D. With that said, it’s definitely a very strange volcano. It has the look and feel of a traditional subduction stratovolcano, yet it’s not sitting near a subduction zone. Unfortunately, the Chinese and North Koreans aren’t the best at volcanology and don’t devote a ton of research towards this volcano.

      • What is even more sad is that they are actively suppressing local knowledge about the volcano. I have a friend from there who did not even know his familly was living next to an active volcano (Baekdu). When I told him he looked it up and read about it, but when he tried to read about through the cencored chinese internet nothing came up about it being a volcano.
        Sadly the chinese do not give a rats bone about human lives being lost through natural disasters.

      • Cbus the paper above (last link) is about trying to identify this anomaly. Like I said it’s technical but explains pretty much how the Chinese are trying to get a better picture of what happens . It would appear that the subducting rocks from the west pacific plate come up against the Eurasian plate and so cannot dive straight under and down . They move more horizontally and break into fragments in this transitional zone. This creates the strange pattern of these subduction type volcanoes so far from the actual subduction Zone.

    • Dunno . Looking at the area on Google Satellite there may be some older calderas to its SW. Could this be an old subduction zone?

      • Note to self – must find time to finish my post! The Sea of Japan saw quite a lot of active volcanism (Ulleung-do, dokdo) with tephra fall out from Ulleung-do’s VEI6 eruption (about 9K yeas ago) reaching as far away as 800kms (Honshu) and is often used as a marker, such as when they study the sediments in Lake Biwa. Most volcanism is associated with the spreading of the sea floor and the formation of back-arc basins when the islands of Japan started to move away from the Korean mainland.. There’s even some postulation that a mantle plume may be involved although not all agree with this idea.
        If you look at the sea floor there’s a quite a lot of interesting volcanic features including seamounts. I have some free time coming up so I’ll get back to writing my post shortly.

        • I am looking forward to the post 🙂

          Actually Baekdu is situated on subducting zone of it’s own. It is an old subduction zone where the Koreas slammed into China. For some reason the subduction zone volcanism stayed active even after the subductioning stopped.
          An alternate reason for that might be that there is proto-separation going on due to the upcoming breaking of the Eurasion plate, a process that is visible at Lake Baikal.

  7. OT: Japan!

    Looks like I’m going there for a couple of weeks in second half of July.

    Looking for suggestions on good photogenic volcanos to visit. Sakura Jima obviously, hope to see some activity there… what else? Anything else restless at the mo?


        • Lurking ……ROFL! One of my favourite films 😀 😀 I think it is a reflection of my life! Quite how I have stayed alive, both physically and mentally, all these years I have no idea but one of my greatest moments on the dance floor was when I was about fifteen and I was strutting my stuff on the local ballroom dancing class one Saturday Night. I felt all eyes on me. I felt at last I could have morphed into Sophia Lauren or Leslie Caron. I felt beautiful!
          Until I looked into the mirror in the telephone booth when I phoned my Dad to come and pick me up.
          My face resembled a fully mature Chinese Panda . 😯
          As I am very blonde , my eyebrows and eyelashes are invisible so I had bought a PERMANENT brown dye and applied it……..carelessly without heeding the instructions. It took weeks to wear off the skin round my poor little eyes……One of the reasons I would never want to be a teenager again ! 😀 😀

          • Oh, Diana, what a funny story! You must have been so mortified! I wouldn’t want to be a teenager again either.

            • Lol Bobbi… I remember this moment with pain and anguish 50 years later 😀 ..It was worse when I had to go to school looking like that! It took a couple of weeks to get reasonably back to normal…..I never ever dyed any bit of me since 😀 😀

    • the HEK strain has gone up very fast this morning – Hekla probably read that article and is reacting against it! 😀

    • Nothing pointing to any reversal in the activity of Hekla.
      All stations are either uplifting (4), stable (3) or in the case of Isakot deflating. This is normal for Hekla, now and then she seems to redistribute magma from one part to another, but the general trend is towards continous uplift and increase in magmatic volume.
      She is quiet right now, but she might at any time stop being that.

      In general though Hekla tend to erupt between December and June, I think this is due to some local phenomenon regarding the water table of ground water.

      Will she erupt this year? Who knows. I really thought she would go off in May. But right now I think she might nap untill Next spring. On the other hand we still have those rapid motions in the strain meters.
      Anyhow, to answer your question. She is not in any reversal.

      Regarding Mayon, she is withing striking range of 5 million people or more. Legazpi city is just a stones throw away.

          • Yepp, one quake every two to four days, often “in line of SIFZ” to towards west end of Dead Zone (at Torfajökull), via Vatnafjöll etc.. So are these really Hekla´s?
            I think perhaps only 30% related, other 70% be reaction from what may (or not) be happening in near future there. Read central spreading. So is Hekla part of the spreading…
            I do not know. At least I am furious in Hekla decived us this spring… 😉

            • Today’s letter is I.

              I is for Islander and for Intriguing.

              Remember children, do not play football on a pitch that has fissures under them.

            • The sweepstake is still going – now if Hekla can wait til 2013 is over … 🙂

            • I also am furious with Hekla for not erupting when I said she would. 😦 Now I shall turn my back on her and she will go off for sure. 😀

              Regarding turning back, I am very busy for the next month so wont be on here too much so she is bound to do something then I reckon.

            • Eyjafjallajokull and Grimsvotn both erupted when I went to the bank. Purely coincidental, I know, but it is a deterrent to visiting the bank 😉

  8. 5,000,000 people within distance of Mayon. That is really scary since it looks like a very powerful volcano placed in the smack-dab in middle of Legazpi city I call that a real gate to hell.

    • Well, it’s not like it’s the first time cities have been built either around or withing a volcano. There are a plethora of cities built on slopes of volcanoes or even with the caldera of a volcano.

      The thing that makes Mayon dangerous is that it’s a highly active volcano, and it’s height and slope has reached a point where it can’t really build itself much higher without toppling over, which is part of the big concern.

      • And in the case of the Philippines you would have to work hard to find a spot that is not next door to a volcano, especially with such a large population. The only thing to do there is good monitoring and mitigation.

      • From my previous comment, I don’t mean to say it’s not a big deal that people build cities so close to a volcano, but it’s more that it’s just surprisingly common.

        • Actually, as the volcanologist Rudiger Escobar Wolf pointed out a while ago in here, volcanoes make for ruddy good fertile soil. So, it is actually advantageous to live close to one. Well, up to the point it goes caldera at least.
          So, we get the algorithm pointing towards it being better to perhaps be blown apart than to be certain of starving to death, and in the case of Mayon and most volcanoes people back when the cities was built did not realize that their at least half friendly volcano was slowly evolving into a real beast.

    • Hi briony … I haven’t seen mention of it here … thanks for the link … its fascinating!

    • Thanks for that link Briony, it really helped me visualise what was happening up on Eyjafjallajökull when the lava was struggling to flow down the glacier. Really interesting!

  9. Just looked at the Pacific NW Seismic site. Rainier, Hood and South Sister, -all have some
    quakes …

  10. I know this is coming from out of the Blue, Has anybody here experienced White Island Volcano in New Zealand? I’m starting to find out that I like unusual looking volcanoes and this one looks really cool to me.

    • There is also this one about the gas sampling over the island on Gns channel

      Edit dfm : I seem to meet a problem, go directly on the channel

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