El Hierro and the art of Bad Science

The first of the phreatomagmatic explotions that was caught on a picture back when the eruption was going at a much higher rate than today. It was most likely not a real phreatomagmatic explosion, it was more likely to have been a combination together with a massive gas release. But this is what will be in store most likely for the residents of La Restinga.

After releasing the sixth missive that volcanic vent affectionately known as Bob is dead, the authorities have now finished the monitoring of the volcano.

This declaration of cessation of activity is contrary to all known data. All released data point towards that the volcanic edifice is still growing at a rate of 10 to 15 meters per 2 weeks. There is still harmonic tremor associated with new magma arriving into the volcanic system from the deep. There was a steady and visible disturbance over the volcanic vent, and the gas-measurements are still above normal readings.

Instead of happily following what is happening the authorities have decided to shut down the web cameras, discontinue active monitoring, abandoning bathymetric scans of the volcanic edifice, and generally trying to hide that there is a volcano on the island of El Hierro.

This is most likely done due to political pressure to achieve a former state of touristic bliss, since it does not have any good scientific foundation.  The responsible organizations have instead chosen to only rely on data that supports cessation, disregarding contrary factual information. This is the Popperian “Art of Bad Science”.

Only problem here is that soon Bob will be hitting the threshold of where hydro magmatic activity will be clearly visible on the surface. Something that was caught on video a couple of days ago by our commentators in here. This activity will only grow during the upcoming weeks.

In 2 to 4 weeks the authorities will most likely have a set of rather distraught residents at La Restinga as they start to see ‘rooster-tail’ explosions surfacing on top of Bob. If activities then continue we are somewhere around 14 to 20 weeks before the volcano surfaces.

Now somebody with a bit of math skill will say, “What? It grows with more than five meters per week! It should be up faster”. Not really, this is due to a cone needing more material to grow, the higher it get. So, the speed of growing in height will decrease over time.

The authorities are probably betting/hoping that the eruption will finish within the next few weeks and save their collective behinds. Sadly they will just then issue a proclamation that the volcano have “re-awakened” to save them.

I am sadly reminded of George Orwell’s 1984, where the author describes “newspeak”, where the meaning of words changes as the powers that be see fit. I never thought I would see scientists involved in the Newspeak of Volcanoes.

I feel very much for the poor residents of La Restinga that in a short time will be scared uselessly and without cause out of scientists running the errands of political buffoons.



617 thoughts on “El Hierro and the art of Bad Science

  1. I haven’ t discovered much since yesterday. This is a summary of what I have found so far:

    1) Activity in Iceland seems to wave up and down reaching peaks over periods of both 60 years but especially 120-140 years.
    2) During these peaks rifting occurs widely in Vatnajokull, not only Grimsvotn but also Kverfjoll, and sometimes Oraejajokull, Askja, Bardarbunga, or even at Krafla, and often but not always with very large VEI5 eruptions.
    3) When that rifting occurs, Hekla never seems to erupt, neither Reykjanes (but regarding Reykjanes there is not so much data to confirm that). Reykjanes seems to be active when Vatnajokull shows little activity. During periods of little rifting activity around Vatnajokull, large eruptions of Hekla and Katla seem to occur often.
    4) Also Hekla and Katla never seem to erupt too close to each other. At least in what concerns large eruptions. They are usually spaced by at least 10 years and often by 30 years.
    5) Large earthquakes in SISZ occur quite often, about every 10-15 years, and when they do not happen, Hekla eruptions do that role.
    6) More than often, these large earthquakes occur right before or after Hekla eruptions, and sometimes even Katla eruptions.
    7) The earthquakes seem to be larger when the peak in Vatnajokull is larger, this has happened for example right after Laki. Sometimes they occur right before the starting of those episodes, other times after, but they do not seem to occur at the same time of such events.
    8) The time of release between large events seems to average 2-5 years when Vatnajokull is active, 10-20 years in SISZ events (including Hekla), about 50 years regarding Katla, and about 150 years regarding the dead zone, and even longer times for activity in Krafla, Westman Islands, Reykjanes, Further away from the hotspot events seem to take longer between them, but this also depends on the region. Tensile regions like the dead zone, snap over longer periods.
    8) Large events at Tjornes seem to occur less often than at the SISZ, over periods of about, yes, 60 years or so.
    9) There is little data, but it seems to suggest that the switch from and out of Reykjanes activity into Vatnajokull appears to have large dead zone eruptions between them. Only wild speculation this.

    This is as best of what I have seen in the history of large Icelandic events. These are tendencies, not golden rules. What this means for present activity?

    Katla is due for a large eruption, but not Hekla. Next large event in SISZ (including Hekla) might happen within 15 years, but no large Hekla eruption. Because we seem to be around a peak of rifting activity from Vatnajokull. This means, that volcanoes like Askja, Kverfjoll, Bardarbunga, Esjufjoll, Oraefajokull are more likely to erupt. Next event at Tjornes seems probably within the next 15 years too. No likely activity at Reykjanes. The big news is that we might be due to a large rifting episode in the dead zone within the next years.

    • This is interesting (as opposed to 1m4 eartquakes), thank you. Especially your #3. At the same time as it explains why Hekla defies our expectations, but why Reykjanes is active in spite of Vatnajökull being so too…? There is one difference between historic times and the present – man-made activity such as artificial lakes and geothermal plants. Would this be enough to explain the abberations? I do not know, but artificial lakes do change local geology (pressure-levels throughout the surrounding areas) and geothermal plants do change the thermal distribution and possibly the plasticity at depth.

      • Why do activity in Reykjanes/Hekla seems opposite of that at the hotspot

        Because I actually think that the hotspot affects both places, but when it channels magma into one area, one rift becomes active, and if the western rift separates, then, this releases a need to rift over the east, and vice-versa. The hotspot is what makes one rift active, and is what makes rifts jump. Now, rifting has happened largely in eastern belt. But I have a feeling that maybe after one last big Veidivotn-style episode sometime this century, we will switch back to Reykjanes.

        I also remember once reading on a paper, that activity over Hekla/Katla seems to be opposite of that of the hotspot focus. We have seen activity at the Westman Islands and Eyjafjallajokull, there seems to be a shift of activity away of the hotspot. So I am not totally sure, if this next peak will feature so much focus in Vatnajokull yet. However last Grimsvotn eruption seems to show otherwise. Maybe we will see about 50/50 activity over Vatnajokull and over the south/southwest.

    • I think that you are in general quite correct in many things.
      I still think that we are one Hekla eruption away before it goes quiet.
      Katla I think is just not “in the zone” yet to take over.

  2. Regarding the last Hekla quake.
    It is most likely only one, it seems to have been in the site of the Raudubjallar eruption in 1554.
    This quake was probably around 2.3M. Raudubjallar and the 1554 eruption had nothing to do with Hekla.

    It is interesting with two non-Hekla quakes inside the Hekla volcanic swarm. First the Vatnsfjöll quake yesterday, and now a bigger one in another volcano. Interesting times are coming I think.
    Might be that Hekla is nearing a very long snooze.
    Since Irpsit have mentioned cyclicity I will now mention the long cyclicity of Hekla. The last 1000 years are really out there regarding Hekla. Normally it is Vatnsfjöll that erupts often, not Hekla. So if that system reactivates, well then it will be calm for about a 1000 years in Hekla before she erupts in one of the large tephras.

    • And that is Vatnafjöll and nothing else. To little coffee to spell really.

      Regarding Saurbaer, it has since yesterday been flatlining. It is not showing any usefull things now. It gets rather apparant since it did not pick up the Raudubjallar quake. And it should have done that.
      There is though a slight possibility that Saurbaer has been picking up magma moving into Raudubjallar.

      • And also, since Saurbaer is not showing data I can not say if it was a magmatic or tectonic quake.
        All I can say after looking at the Mjoaskard and Haukadalur SILs is that it was definitly only one quake.

    • I haven’t told this, but I think Hekla just started what I call a rifiting episode in that broad area of South Iceland. Something that also happened before in Reykjanes in 1200-1300, or in Krafla in the seventies, or in Vatnajokull very often.

      This episode explains that the area has been rifting quite regularly since 1947, with frequent Hekla eruptions, and this could eventually lead to Vatnfjoll also erupting. (My wild speculation)

      We know that SISZ has readjusted in 2000/2008, Hekla erupted in last decades, Eyjafjallajokull in 2010, and Vatnajokull in 2011 and during last years. I do not know if Vatnsjoll needs to rift, because so many change has been happening around it, compared to last centuries. The area which is due to rift, is actually the dead zone, somewhere between Katla to Hamarinn, and also around Kistufell and Kverfjoll. Those are my bets.

    • Carl, there also seems to be a focus over the tip of spreading rift: Westman Islands, Eyjafjalljokull, and maybe west of Hekla 😉

    • The SIL on Santorini that is showing horkloads of human interference is the THRA2. That I do not even have a link to any longer since it is basically useles..
      SANT and THRA are fairly usefull if one combines them.
      If tremor is high on SANT and popcorn is increasing on THRA, then it is most likely something real.

      Personal rule of mine, always double check with another reliable SIL.

    • Winds maybe? Be nice to have a wind reading up near the Sant sta. The airport seems to open at 7 am local time and winds were blowing then. But even if it’s calm at the airport there is not a certainty that the top of the Mt. is calm. Sant seems to be sensitive to wind. Somewhere there is a statement by a member of the observatory deriding the claims of tremor readings on SAnt and not Thera, suggesting it was folly for the tremor to go up the mountain rather than the shorter leg to Thera . Thought that was like whistling in the dark. A possible reason is the SW-NE fault damps the signal. But in spite of the new official approach to discussion, some topics may still be damped.

      • It is actually really hard to read those signals since we do not get the spectral chart for them. Without them what we get is at best good enough to pick out the more heavy readings.

    • That is just madness.
      Perfidio Almas is just slowly going ever more nuts.
      First time I heard about the guy was when he declared that a diving photographic competition would be held in La Restinga right after the eruption had started, and then he has just done and/or said one ludicrous thing after another.
      But saying no to 3M€ is probably going to make him unemployed. Politicians are normaly allowed to be stupid, but they are not allowed to saying no to free money.

        • It is rather intriguing.
          Politicians rarely say no to getting more money.

          It might be something so simple as that Perfidio Armas is a member of another party than the one that rules the Canaries as a whole.

        • It’s not external money as far as I can tell; it was a request to allocate money from within the Canaries own budget. From Diario El Hierro http://www.diarioelhierro.es/

          The headline in Spanish is: “CC y PSC rechazan destinar 3 millones de euros a El Hierro”

          “EUROPA PRESS, s/C Tenerife (28/3/2012)
          The Parliament of the Canary Islands has rejected with 31 votes against a proposition No law (NLP) which was intended to urge the Government of the Canary Islands to appropriate to divert its funds three million euros to provide a specific plan for the island of El Hierro.”

  3. @Hekla:

    And now it got really weird…
    They just adjusted the latest Hekla quake.
    It was a 2.2M and it happened 7.5km down straight under Haukadalur SIL-station.
    So it is definitly back inside the Hekla volcano again. This is the southern end of the Hekla fissure swarm. There is currently a pattern of Popcorns taking place.

    • I think this one, and yesterdays quake on the other side of Hekla could be compression quakes as the fissure of Hekla proper is moving due to pressure changes in the system due to the very large change of location of the magmas inside the Hekla system.
      There has been lately a very large deflation in some areas of Hekla. Only problem is understanding where all that Magma is going.

      • Is it time to open yet another window on my desktop?
        Carl, how feasible do you think it is that if a body of rock that was close to the solidus rapidly melted due to an influx of hot magma into the system that this might trigger a decrease of volume? (tortured grammar, sorry about that but you know what I mean).

        • The volume would stay the same really. It should actually increase a tiny amount since higher temperature as it melts actually lowers the density (inflates) the rock.
          Rock expand as it gets hotter.

        • Well, it seems like Hekla does not operate on Cumulative Seismic Release. There has been more quake energy released this time around than before the last eruption.
          My guess is that this is a sign of the magma moving to a new chamber is reaching the pressure threshold.
          I actually am starting to believe that Hekla is going to throw us something really unexpected, like a fissure eruption or something. Because the magma is clearly moving away from Hekla proper, propably to the east like it shows on Lurkings old plot. Would have been nice to see if the movement is continuing in that direction, or is something new is happening.

          I though have an alternate idea, but that is so out there that it is probably ridicolous. The watertable might actually be sinking causing the deflation. The thing that makes this a bit less ludicrous is that Hekla is reported to dry up its wells before an eruption. And that could only happen if the table lowers. Just an idea… But if it is correct we are just days or weeks away now.

  4. Volcano Activity in Indonesia on Thursday, 29 March, 2012 at 03:10 (03:10 AM) UTC.

    An active lava dome is growing inside the summit crater of Krakatau volcano. Our tour expedition leader Andi just returned from a visit and reports that the dome is now about 100 m wide, and has 2 main active vents that eject jets of incandescent gas.
    At night, the glow from the dome is clearly visible from Rakata and Sertung islands, and a continuous intense solfatara plume is rising about 500 m above the summit. Andi and our group observed also that there are now more and larger fumarole fields on the southern part of the cone. According to our observations and the opinion of local scientists, this area is inflated due to the pushing of the lava dome. The seismic recordings from the observatory of Krakatau also show an increase in activity. On 26 March, there were 138 volcanic-tectonic (A-type) earthquakes and 300 long-period (B-type) quakes alone. The question is how long the lava dome remains quiet and purely effusive in style. Explosive, also larger vulcanian-type ones, activity could occur any time.


  5. Volcano Activity in Montserrat on Friday, 23 March, 2012 at 20:07 (08:07 PM) UTC.


    Updated: Thursday, 29 March, 2012 at 09:59 UTC
    St. John’s Antigua- For the first time in two years, the Montserrat Volcano Observatory (MVO) monitoring the Soufriere Hills volcano noted unusual activity, with increased seismicity, accompanied by ash fall. Acting Director of MVO Roderick Stuart said the change, which was noted on Friday, is a break from a long state of pause, thus a reminder the volcano is still very active and residents there must always be cautious and aware. Stuart reported, “Last Friday we had the first sort of activity in the volcano in over two years. It generated some ash and because it was the first activity we had in two years, it was almost a precautionary measure that we closed daytime access to Zone C just in case this activity started something bigger,” Stuart told OBSERVER Media. The authority also noted increased steam venting activity on the volcano and a new steam vent (fumarole) that appeared on the northwestern face of the lava dome behind Gages Mountain. Audible roaring associated with the venting were intermittently heard from the Observatory, 5.75 km northwest of the volcano.

    The seismic network recorded nine rockfalls, 105 volcano-tectonic (VT) and four hybrid earthquakes. Additionally, two swarms of VT earthquakes occurred. Earthquakes in the second swarm were described as markedly larger than those in the first. Consequently Zone C on the volcanic risk map was closed until Tuesday when there was a decrease in volcanic tectonic earthquakes below the volcano. Zone C comprises Cork Hill, Delvins, Weekes, Foxes Bay and Richmond Hill. Daytime access means that persons can visit these areas using a vehicle from 8 am to 4 pm while children must be accompanied by their parents. “There is nothing to worry about now but it is just a reminder that this volcano is potentially active. After two years of nothing happening people may get a sense that the eruption is over, but it is not,” Stuart said. He said there have been five pauses in activity since the first eruption in 1996 and Friday’s end to the last state of pause could mean the beginning of another period without activity or the resumption of lava extrusion, without an explosion.

    “We are just very wary of when something like this happens, we have to be very careful and incorporate the measures. There have been various predictions as we try to forecast what could happen since we have to be ready for anything,” Stuart said. As it relates to the new stem vent formed on the dome, Stuart said it would be monitored, though they often “go away.” The ash fall on Friday did not disrupt life on the island as it was light and most of it occurred on the uninhabited part of the island. The volcano is monitored around the clock and officials visit the dome once a week using Caribbean Helicopters, a helicopter company based in Antigua. A 1997 volcanic eruption killed 19 people and buried much of the island, including its former capital, Plymouth, which is now abandoned. Half the British territory’s 12,000 inhabitants left.


  6. Interesting comment on Erik Klemetti’s blog in his post “Looking Back at the 1982 eruption of El Chichón in Mexico”

    “Over 75 percent of the major eruptions for the past few millenia have come from volcanoes with no known historical eruption. This means that is it vital to map all volcanoes in volcanically active regions to better understand their patterns of behavior. It also means that monitoring should not be limited to those volcanoes that are historically very active, but also to volcanoes that could pose a danger if active resumed.”


    • Earthquakes also happen on “newly discovered faults”. Since I live close to the New Madrid Fault, it worries me that some scientists think the fault is “dying out”. We all know what happens when something is declared “dead”.

    • Kind of makes a mockery of the Decade Volcano programme as all but two (or possibly three) of the 16 volcanoes selected have had multiple eruptions over the past hundred or so years. As an example both Etna and Vesuvius are on the list but not Campi Flegrei which is utterly moronic as little is known about the behaviour of the latter and especially since its destructive potential as measured by both VEI and potential deaths is well over a hundred times greater than that of Vesuvius and tens of thousands of times greater than Etna.

      • Not really. The aim of the Decade Volcano programme is to achieve a better understanding of the volcanoes and the dangers they present, and thus being able to reduce the severity of natural disasters.

        A volcano may be designated a Decade Volcano if it exhibits more than one volcanic hazard (people living near the Decade Volcanoes may experience tephra fall, pyroclastic flows, lava flows, lahars, volcanic edifice instability and lava dome collapse); shows recent geological activity; is located in a populated area (eruptions at any of the Decade Volcanoes may threaten tens or hundreds of thousands of people, and therefore mitigating eruption hazards at these volcanoes is crucial); is politically and physically accessible for study; and there is local support for the work.

        Source: http://en.wikipedia.org/wiki/Decade_Volcanoes

        It just means that if a “dormant / extinct” volcano shows signs of waking up, don’t ignore it. If it goes on to show eruptive activity, wait a sensible amount of time after it initally quietens down before assuming the eruption is over. Because it might take a few attempts before it works up to a large eruption.

        • Karen, most of the Decade volcanoes already were adequately monitored and most of the governments concerned certainly had/have the economic means to support such monitoring. What irks me is that there are several potentially far more dangerous volcanic systems ignored (such as Campi Flegrei, Eifel, Monte Albans and Taupo) and also several where the concerned governements do not have anywhere near the resources required which leaves these systems virtually unmonitored such as at Vanuatu or Rabaul.

          • I understand what Karen is trying to say. But you are right.
            However, what could be done if Campi Fragrance goes boom? Evacuate the whole Mediterranean?
            As for Colli Albani, I couldn’t have ever imagined that it posed any real threat (have lived on it for a while… and on Eiffel too… gulp!).
            Well living in Rio is not really safe either…
            As for Hierro, I really think people should get used to it, as long as efficient information keep people aware of any possible dangers.

          • Good, because that was not one of my best worded comments. The last paragraph should have been the first. 😳 Thank you for clarifying. 😀

        • Camping Flagrant and Taupo are well monitored systems.
          Not even a gough gets past those two.
          And you forgot Ischia in your Naples list.

          Also a couple of the african volcanoes merrit the status of decade volcanoes, Mt Fako at least is close enough to a lot of people.

          • Not a list Carl, examples. Mt Fako is another example of the second category of a dangerous volcano where the local government does not have the resources required to monitor it adequately. The Decade list should have identified ALL and not just 16 dangerous volcanic systems in close proximity to large bodies of humans and focused primarily on those where the local government was unable, technologically and financially, to supply adequate monitoring. With the latter in mind, Rainier’s inclusion is ridiculous as USGS is the best funded of all bodies charged with the surveillance of volcanoes even if Rainier certainly is potentially a very dangerous volcano indeed.

          • I could imagine that camping flagranti would get a lot of monitoring for free.. and those goths around Taupo don’t stand a chance! Ha.

            But maybe we putting the cart before the horse. Where could the next big surprises be? The Rhine Graben?
            South Australia?

          • The Kerguelen Hotspot having a VEI-9 and then another trapformation with 10 000 cubic kilomters of lava ejected per year into the ocean…

  7. Thngs certainly are moving in Iceland. Hekla is showing recordings that I have not seen in over a year of watching.

    What really worries me is that the RUV Hekla cam is not working and so I cannot check on the state of the Dalek. Poor thing he is so exposed. :cry

  8. For those who understand German, a cool documentary on Etna, starring, Dr. Boris (Königin der Nacht) Behnke! 🙂

  9. The Booming sounds are back at Clintonville apparently. There has been suggestion that these were caused by a minor earthquake swarm, but there is a lot of skepticm over this as the largest quake was a 1.5, and the quake pattern does not really add up to the frequency etc of the sounds observed.

    There is an alternative theory that it is being caused by glacial rebound, and a good discussion of the subject here http://grace.jpl.nasa.gov/data/pgr/ (which is relevant to our volcano discussions too).

      • Good info. Another schleep-little night? Carl, have you checked on all your dragons today. One might have escaped and blowing life into Icelands lava systems?

        • The likely Culprit would be Shadow… He is a rather fiery one 😉

          This is from the high-res data from the HAU sil. In this case giving the 2-4Hz range.

        • Every dividing line is 10 minutes. So this is much higher res than the public IMO plot.
          I love how it looks like heartbeats.

          • Ah, brain got swamped for a second.
            @Carl – from 14.xx something thread – Water table. One observation from yesterday is that surface water/mýrar in Saurbær/Holt area were full, either from recent rain or thaws. Next time I will try find small streams and note their status (low, average or full) easy to see actually, even for outsider. I have training in making observations.

          • I meant more the ground water level.
            If that sinks the land sinks. And volcanoes sometimes do things to the level of the ground water. And that is often not visible. But the interesting thing would be if the small water run offs from Hekla itself had dried out.
            The rivers would largely be unaffected, especially this time of the year.

    • Bruce, the link was posted by Boris on FB, but I think the El Hierro footage had already been posted here.
      Great to remind us, thanks!

        • Not seen that one yet, but the one about Hierro also declares Hierro as dead (hehe…)
          Well, fishes and their predators are coming back and they say the volcano is only degassing. Hope that the underwater ecosystem will soon recover.
          Now, a look at Auckland…

        • Bruce, 57 volcanoes! Who could have imagined?
          That is dangerous!
          For that reason you moved to Germany, you placed your bets in Eiffel rather than Auckland or Taupo?… 🙂

  10. OT: Waking up.

    My head doesn’t generally work right until I wake up. Coffee does the trick, but music helps to get you through until the coffee comes online.

    This is this mornings recipe.

    Korn: Freak on a Leash
    Eisenfunk : Pong
    Robin Trower: Day of the Eagle
    Kiss: God of Thunder
    Varuca Salt: Volcano Girls
    Ramstein: Ramstein
    Pendulumn: Out There

    And., my apologies to the classical aficionados. Short of Rush’s incorporation of segments of Tchaikovsky’ 1812 Overture in their song “Anthem”, I have a hard time dealing with it. Though beautiful and technically complex (and I don’t mean that lightly, it’s all brilliant work) I just can’t maintain an interest.

      • What took me by surprise was Eisenfunk’s Pong video.

        Evidently there is a genre of some sort of industrial goth that wear leggings and gas masks. I laughed my arse off watching those two Predator (as in the movie series) looking girls dancing.

        Not ridiculing… it’s their thing. It just struck me as odd peering back at where todays youth is at. (way out of my age bracket, I have grandkids that old)

      • lol, my other half takes great joy at “sharing” (reads as “lectures”) with those who vehemently object to metal how many of it’s musicians are classically trained; that the music itself is quite technically creative, (i.e.: that it isn’t just noise), and then provides case studies.

        Must admit I did enjoy seeing Opeth at the Royal Albert Hall, or perhaps that was just the joy at watching the parents accompanying their underage children squirm wishing they hadn’t drawn the short straw 🙂

      • Want some fun? Go listen to Aerosmiths “Train Kept a Rolling” and Foghats “Honey Hush”.

        Each song was written by a different person and had a different sound. After Johnny Burnette did a cover of them in the 50’s they assumed a similar structure and feel. This can be seen in the Aerosmith and Foghat versions which follow the Burnette rendition.

    • Oops… I misspoke. Rush used parts of Tchaikovsky in “Overture” on the 2112 album.

      Went out and had a listen to verify my recollection.

      Reading a bit, it turns out that some of Ayn Rand influenced some of their work.

    • Veruca Salt – bringing back the memories now

      This mornings wake me up:
      Black Betty, by Spiderbait in this instance and
      Pendulem’s Tarantula

      And Black Betty for those that want a listen:

  11. A couple quakes in the Askja caldera

    29.03.2012 15:16:00 65.041 -16.753 1.5 km 1.8 99.0 7.0 km W of Dreki
    29.03.2012 12:27:13 65.025 -16.671 3.6 km 1.1 99.0 3.5 km WSW

    • Wow, wonder what caused that? Jackhammers? At present I have two problems with the Santorini SILs – a) I’m not familiar with them so I have little idea what is normal, and b) rarely does more than one station show a particular pattern. Without correlation, it’s hard to make any deductions…

      • @ henrilerevenant

        I’ve been following the seismographs or many volcanoes in Costa Rica to try to guage what is and is not occuring. Turrialba has its own Webcam so I was able to watch degassing and busy seismograms simultaneously and sometimes they did not seem to be behaving the way I would have expected. I have come to the conclusion that Chouet is right: each volcano has its own signature but there are still some commonalities. Rock breaking is obvious; magma intrusion depends on how free the conduit is and whether there is a cryptodome.

        Far too complex for me but so interesting. Here is a link to OVSICORI UNA for a great bit of science KNOW-how!


        Bernard Chouet ( who accurately predicted when Redoubt was about to erupt) is a great teacher. Please Google him.

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