Posted on by Jón Frímann

New earthquake swarm in Katla volcano during the day

Today there was a new earthquake swarm in Katla volcano. This earthquake swarm was in the caldera of Katla volcano, same as the earthquake swarms that have happened inside Katla volcano since July, when this pattern of activity did start.


Current earthquake activity in Katla volcano. Copyright of this picture belongs to Iceland Met Office.

It has been few hours since the earthquake activity did stop in Katla volcano. If the pattern that has been ongoing for the past week and longer there should be a harmonic tremor spike in few hours time. But that it currently hard to know if this pattern is going to hold up or not. But I have every reason to believe that it is going to do so. For the moment, all that can be done is to wait and see what happens next in Katla volcano. At the moment, I have not seen any harmonic tremor spike during the day or at current time when this blog post is written.

154 Replies to “New earthquake swarm in Katla volcano during the day”

  1. To those who speak about the crazy connection between solar weather and volcanism (“earth changes”) we will put this theory to the test this weekend! (please read until the end before commenting)

    There was a big solar flare a couple days ago, and it has strike now our planet, with ground currents even observed in Norway. There is a significant geomagnetic storm occurring just now! So, we have a big solar impact and a volcano close and nearly ready to erupt (Katla). Katla had had many changes to erupt in recent harmonic tremor events but nothing happened. Now it has this big solar flare impact, so if any causal link exists, we should see it this weekend.

    If Katla erupts this weekend, then I will start giving some belief to that crazy theory. Otherwise, we will refuse that theory very clearly (Katla had its change with this solar activity and did not erupt), so we can shut down this debate and be settled with the fact that solar activity that does not trigger volcanism on Earth!

    Tough challenge no?

    Disclaimer: I am currently thinking that solar activity cannot affect at all volcanism on Earth. And I think Katla will erupt not triggered by the Sun, but its own internal magma dynamics.

    I bet 90% that Katla will remain more or less quiet this weekend, just with its ongoing swarms and tremors.

    1. And of course, I have seen so many major flares striking directly the Earth, and nothing never happened afterwards. So, that’s why I can’t understand why people still keep this link between solar activity and volcanism.

      The only stuff it can happen is a disruption of our own power grids, but still that needs a really big flare.

      Now, if you talk about a link between solar activity and climate, that’s another thing, definitively one affects the other to some degree.

    2. Irpsit says:

      “I am currently thinking that solar activity cannot affect at all volcanism on Earth. ”

      You are FLAT OUT WRONG in this statement.

      Auroral displays coupled with erupting volcanoes make for some of the most picturesque web cam displays… 😀

      2. Wrong set. Cant find the one i was looking for. But still a good photo at the very top.

    3. Where did you get the “ground currents even observed in Norway”?

      Today’s several M-level flares and the CME will contribute the combined effects on the earth. Currently the condition is well to induce some Richter 7 earthquake around somewhere.

      For Katla as long as the cumulative strain energy reaches the critical level, it will cry out. If this weekend we do not hear the Fat lady singing, we should wait for other 27 days.

    4. Difficult to say either way. It is hard to say no effect at all but the effect may be small as magnetic storms / solar flares are only known eally upset sensitive electrical / electronic systems. If there is a lot of magnetic material in the magma, the impact might be greater. Suspect there isn’t enough data around to do more than hypothesise.

    5. The connection between Space Weather and events like thunderstorms, earthquakes, and eruptions is in its infancy. The connection between these things is so close to being proven that it make people want to predict things that seem insane. The only problem with saying a solar flare will cause a volcanic eruption is the variables that are involed are… astronomically huge!

      The solar activity may cause Katla to erupt… but not tomorrow, or next week. It may not cause the Cascadia Fault to shake and cause a tsunami…. tomorrow. But the shaking that causes one rock to shift ever so slightly, bumping into a loose sandy stratta line, causing a rise of water…. a butterfly flaps its wings in the Indian Ocean and you get rain in Montana instead of Snow.

      The most obvious connection is a third-party connection, in my opinion. The compression of Earth’s magnetosphere by these storms has caused weather patterns to reverse temporarily. A huge shift in atmospheric conditions can help to spur activity. All of the glacier melt from this summer has started the cap to unscrew. If a major high pressure system (say, 1020+ mb) is suddenly, within a few hours, pushed aside and a low of 990 mb rolls in, then it would be like putting a marshmallow in a vacuum. And that could be all that is needed. If this event repeats over a few days, then its like old elastic in your underwear… eventually it snaps and your unders are around your ankles.

      …And that never happens when you want it to!

  2. @ Irpsit and other Icelanders
    Please, are any of the webcams on any of the sites in Iceland capable of showing an aurora, it’s something I’ve never seen and not likely to here in UK ‘cos of light pollution.

    @any UK contributors to Jon’s site
    Has anyone heard or seen anything in the media about the Katla (etc) happenings, I haven’t; no doubt if anything drastic does blow it’ll be the usual British response – ‘it’s-not-here-s- it-doesn’t-warrant-mention’ or ‘oh b….y h..l we’ve had airspace disrupted and we didn’t know’. Probably half the UK’s never heard of Katla let alone where and what it is.
    Sorry another of my short-fuse rants!!

    1. @ AlanUK here and not heard a thing! At least they can pronounce Katla, so the language barrier should not hold the Brit news back!

      Here is supposed to be a good cam for the aurora. I may be wrong but I was given this cam link when I asked the same question about where to look for the Auora,
      http://www.earthcam.com/cams/iceland/reykjavik/

    2. Good point: not heard anything recent. There was mention of Katla after Lady E erupted saying that Katla was bigger and had a tendancy to erupt 18 months after Lady E, and that the eruption would be much bigger. The Icelandic prime minister’s warning then to prepare was also reported.

      People I have mentioned Katla to are not really aware of it.

      The silence is a bit of a concern as, based on previous incidents, it has taken the government three days minimum to convene COBRA. Clearly if Katla does produce a VEI 5 or more (hopefully it won’t), then that response may well be inadequate. Katla may well do a lot more than just produce a lot of ash.

      Might start a few low-key reminders.

    3. Not come across anything in UK media either, but the aviation industry is aware of the risk according to a previous post and is issuing ash forecasts. Therefore if the government claim it “took us by surprise”, they will show themselves to be either incompetent or lacking in honesty. Especially as some of our European neighbours’ media appear to be tracking the situation.

  3. @ Watchman from the previous thread.

    Regarding the “stupid question” which actually is not stupid at all.

    I guess all volcanoes may experience a calderaforming event. Katla can do that also. She did at one point and may very well do it again. Odds are that the next eruption will not be as violent as a caldera forming eruption but one never knows until the eruption is over.

    But still, if she erupts violently and more or less empties the magma chamber the floor could collapse. But that would mean a large VEI6 or even a VEI7 eruption for her to eject more magma at a faster rate than it can be “refilled” and on top of that the structure needs to get weakened aswell to the point of fracture.

    But still I dont believe it will come to that. 🙂

    And again..Just my 2 cents and as a rank amateur its nothing to hang ones hat on. 😉

  4. Nothing at all in the UK press as yet, if they do it’ll probably be just the usual scaremongering, and worries about airplane schedules… grrrr. They never mention the people and animals that may be destroyed.

    1. I do remember watching Channel 4 news in the UK during this years Grimsvotn eruption & they did cover how people (in certain places) & farm animals were coping, they did it for Eyja eruption last year also.

  5. When I went to Iceland in 1997 I went to Landmannalaugur – this is before the time of Google maps and things like that and the maps I’ve had of Iceland never mark it as a town (as it’s not) – I remember going to Eldgja and the Laki fissures on the way so I’m guessing it’s a lot closer to Myrdalsjokull than I think it is.

    I’ve also been trying to work out where the campsite in Porsmork is that I stayed in – it was a long way up the valley over some ‘rickety’ bridges and had like a concrete-style eating gazebo. People talked about going over to Skogar so it must have been close to the Fimmvorduhals walk.

  6. Are these 2 EQ on the rim of Askjas caldera (which is fiiled with water and forms the Öskjuvatn lake <- did i understand that correct?) suspicious in any way?

    Friday
    09.09.2011 18:10:57 65.013 -16.707 4.2 km 1.1 57.62 5.6 km WSW of Dreki
    Friday
    09.09.2011 18:10:56 65.050 -16.769 10.5 km 1.3 42.47 7.8 km W of Dreki

    1. The quality is too low to really know where they were. Epi/hypocenters might be changed after they have been checked out. If they get checked.

      57,62 and 42,47 as poor quality.

  7. Looking now at the recent quakes in the Katla caldera the pattern from a few days ago is really starting to be erratic. They are really all over the place. Now i realize they dont occur in 2D and they have different depths but still..Bugs me. 😉

  8. @peter pan: SpaceWeather have mentioned on it’s site about ground current caused by the Geomagnetic storm. It should be a good weekend for the aurora, perhaps some of us in the UK will spot them.
    @Daniel_swe: Is this the set of aurora & eruption pics you were looking for? http://www.flickr.com/photos/stefnisson/4507697271/.
    The weekend has returned & it could be Katlas turn on the Brennivin! 🙂

    2. Shame those appear to be fake pictures as the aurora is superimposed over the ejecting lava. Well I don’t believe the aurora comes down to ground level!

    1. Cool! Thanks Alli! I’ve bookmarked it and will enjoy being a member. Looks like the rest of this blog’s followers are deep in conversation! I’m a complete amateur so any and all volcano info and chat is welcome. Thank you!

  10. I dont know whether this has any relevance but there is a lot of bird movement out there at the moment and 1000s of birds are migrating south which is very unusual behaviour at this time of year. Do you think they pick up on the magnetic storms / solar flares etc and are sensitive to the electrical currents in our atmosphere. You often hear of birds having a massive exodus just before a volcanic eruption so who knows…………….just a theory.

    Fantastic photos by the way 🙂

    1. In the UK, birds traditionally migrate south in the Autumn. We are fast approaching Autumn.

      1. Leaves on some trees where i live (Somerset UK) started turning brown & falling the beginning of august!!

  12. BreakingNews Breaking News
    More: Reuters reports slight rattling from Vancouver quake felt in Seattle; Seattle police say no signs or reports, damage
    há 1 minuto » BreakingNews Breaking News
    Magnitude 6.7 quake off Canada’s Vancouver Island; Tsunami is not expected – USGS, PTWC
    há 12 minutos

    1. I felt it here in Seattle, 9th floor office building. Just a very gentle swaying. I noticed it first because the water in my cup was rocking back and forth instead of the ripples I’d see from normal vibrations in the building.

      I really hope it is not a pre-shock for “the big one” they’re expecting here in the CSZ. http://en.wikipedia.org/wiki/Cascadia_subduction_zone

    2. Dangerously close to the CSZ.

      OT (at first glance): Seems like everytime Obama speaks, there is a major quake or hurrican or volcano’s start to rumble. I am doing some statistical correlation analysis on this to prove the correlation. Given that he is the antichrist, this would make sense. Disturbances in the force mirrored by the earth as we are one with mother earth. So this debunks the CME theory as CMEs are actually caused by these disturbances, which lately seem to be coming directly from Obama and sometimes from Trichet or that Italian nut job.

      1. I thought of doing that on extreme weather events in the UK and the correlation with UK politicians doing u-turns. I bet it would work too. That’s statistical correlation for you 😉

      2. btw, for those who didn’t get my punch line: CME = Cranial Mass Ejection. Its a syndrome where the afflicted has a complete loss of organized thought and s*** just flies out of their brain from nowhere.

      3. Classic!
        Craig, don’t think extreme weather events for u-turns will work. Met Office posts an extreme weather warning on *everything* these days, including sunshine. Or maybe it will correlate anyway!

  13. UK here and I have been watching Katla’s activity since Eyjafjallajökull erupted. Love the cams and Jons site with updates. Everyone I know knows about what is happening due to posts on facebook myself and other volcano watching friends make and I believe the some daily paper mentioned what’s going on yesterday.

    Anyway back to watching the cam and reports.

  14. Looking at the pic by Mark on the prev post where he pointed out how circular the recent Katla swarms appear on the IMO pics. Without depth it’s hard to get a sense of what is possibly happening down there. I want to flip the IMO pics horizontal so I can see what’s going on below ground. So……being very cheeky here….

    Could anyone do a plot based on depth of these recent swarms (say past two weeks) with each event colour coded so we can see what it happening with each swarm? Would this show where intrusions are focused and how one swarm affects then next? (i.e. one magma intrusion causes stress in an adjacent area) It could all be in my head but I have to blame everyone on here for that 😀 I doff my cap to those who produce the charts for us to digest on here. I do that myself but on a far far tinier scale and look in awe. Thank you for helping us all understand Iceland that little bit better (even if it takes others to tell us what we are looking at).

    OT I’ve yet to see an aurora in the southern uk – not because of light pollution but every time there’s something decent in the heavens it’s cloudy :s

    1. Looking at the pic by Mark on the prev post where he pointed out how circular the recent Katla swarms appear on the IMO pics. Without depth it’s hard to get a sense of what is possibly happening down there. I want to flip the IMO pics horizontal so I can see what’s going on below ground. So……being very cheeky here….

      http://i.imgur.com/QtroP.png

      The hotter the color, the more recent the earthquake.
      Last 14 days plotted.

      3. See the post at the bottom on the page. Unfortunately I’ve written the capcha wrongly and the system forgot I was replying to you.

      4. Excellent and wow! Thank you Mr Moho.

        I can see why some have been speculated as hydrothermal in origin. Are older events (the darker colours) forcing heat up to melt the ice above (convection I am thinking but please correct me). That is my very unqualified opinion looking at the data as a lurking rank amateur. What do the more experienced heads see going on (if at all beside lots of movement)?

        Interesting also what’s happening outside the caldera to the south east.

      5. That’s really interesting. There seem to be some clear focal points. How does your analysis match the known topography of the caldera?

  16. Could someone please tell me which of the web cams offers the best view of the Aurora Borealis?

      2. Suzie to see any auroras it would be best to have a north facing view. I have not had a chance to check all Mila’s cams.

      3. Looking north is not “a criteria”, northern lights were dancing over Reykjavík (due east) earlier.

  18. Last 360 days plotted. The hotter the color, the more recent the earthquake. It’s quite a mess however. Note that in the previous graph I did something wrong and older earthquakes were plotted ABOVE newer ones. Here is the originally intended opposite:

    http://i.imgur.com/fabgX.png

      4. The older purple quakes appear to be over the cryptodome as shown in this diagram.

        http://en.wikipedia.org/wiki/File:Eyjafjallaj%C3%B6kull_en_Katla.png

        The quakes also appear to be at shallow depth, which fits with the description of a cryptodome.

        wiki descrption of cryptodome: –
        “A cryptodome (from Greek κρυπτός, kryptos, “hidden, secret”) is a dome-shaped structure created by accumulation of viscous magma at a shallow depth. One example of a cryptodome was in the May 1980 eruption of Mount St. Helens, where the explosive eruption began after a landslide caused the side of the volcano to fall, leading to explosive decompression of the subterranean cryptodome.” source http://en.wikipedia.org/wiki/Lava_dome#Cryptodomes

        Could it be that pressures building up below the main Katla crater are having an impact on the cryptodome. If this is the case, it suggests that the walls of the main crater could have been compromised and that sideways release of pressure is greater than upwards. I assume such a situation could impact the dynamics of any eruption, with a greater area of pressure build up over a longer period and a possibility of a larger eruption. 1918 is a long time back, historically Katla eruptions (above ice) have been far more frequent.

  19. What can i say.. ! Amazingly quick, thank you.
    It is interesting how what seems to be an initial set of quakes (in purple) below
    Godabunga, may have released enough strain/pressure to allow what appears an upwelling of magma (?), represented by the later ( in yellow) towards the main caldera as your depth charts show. From 23 km down, thats 1/2 way to the moho if my memory serves right.

    1. It’s awe inspiring and humbling to think of the immense forces acting under iceland and a volcano is just a tiny outlet of that. I know we have to becautious about what we are seeing but these charts really help visualise that process – much better than my old geography books anyway 😀

  20. Those are authentic ( I am Icelandic and know the photographer personally) and the the “lights only seem to reach to the ground because of a mountain in the back ground, light from them penatrates the smoke giving the illusion of being superimposed.

  25. Friday
    09.09.2011 21:37:26 63.601 -19.293 9.0 km 1.1 34.58 4.8 km SSW of Goðabunga
    Friday
    09.09.2011 21:32:31 63.657 -19.136 15.4 km 2.3 61.82 5.9 km ENE of Goðabunga
    Friday
    09.09.2011 20:54:13 63.568 -19.237 5.3 km 0.5 39.52 6.9 km W of Hábunga

    Do we have a harmonic tremor spike at ALF and HVO stations?

    1. I missed it live, but I have just watched the “time-lapse” three times! Thank you for the link! 🙂

  27. Thank you Jon for this amazing site, and thank you to all the people who post here, for all the information and learning you share. I have no background of any kind in this science, so please forgive me for asking this.

    When I look at this: http://hraun.vedur.is/ja/myr/myr_str.html#img
    what am I looking at?
    It looks so dramatic and gets referred to regularly. I suspect this question has been asked before and apologise for bringing it up again.

      1. Thank you Jay. As an indicator of stress at that location, is it just part of a cycle? ie; goes up and then back down again?

      2. It’s a cumulative plot. Each event (quake) that occurs in the sampling area gets added to the plot, thats why it always goes up. The plot (as noted) is the energy of the event, and it’s one of the more vexing plots that they make that I can’t quite duplicate.

        Once an eruption occurs, they generally start a new plot, such as this one for Grimsvotn.

        http://hraun.vedur.is/ja/vatnajokulsvoktun/grf_uppsafn.html

        In the case of the Mýrdalsjökli plot, they are running the three activity areas on one plot and chose a common starting point so that the energy release in each area can be compared to the other areas.

      3. So do we expect an eruption when the graph gets to 5.0e+14 for the Katla plots? Or does the level differ for each volcano?

      4. Differs… and it also differs from run up to run up.

        Its not of any great predictive value other than noting how much energy has gone off there as compared to previous events at that location.

        There are far too few eruptions that have been monitored like this to be able to make any real predictive analysis… and each volcano and circumstance has a huge number of variables that can affect what actually happens.

  28. Guys! Fantastic northern light tonight here!

    Now it calmed down a bit, but I am waiting for those super-bright lights again!

    Also the moon is glowing with a yellowish hue due to the much ash blown from Grimsvotn over here the south Iceland. The wind is a fiercy northeast, and very very cold. Only 0ºC now, and freezing wind.

    It’s a surreal night tonight

  29. I am only cooking dinner now as of 23:25. I couldn’t think about coming home with such surreal auroras. Finally, I got some rest now. But the full moon glowing in the ashy sky is still very damn weird and beautiful. We’re lucky that the wind has blown the ash towards here yet. I really don’t like it ashy weather.

    1. that has got to hurt. Excellent link.

      Jon – do you think this solar/seismic discussion is better suited to your space blog, rather than here so you can keep it strictly seismic in nature? What is the link, I remember you posted it not long ago. Thank you.

      2. All the best with the new blog Jón, i will drop in for some enlightening information and share some. Admiration for your emphatic approach. More research (on my part) is ongoing, most needed.

      3. Youtube video titled “Sudden Cosmic Global Warming” shows the north pole temp rising by 50 deg C, and the cause?…. a massive flare fom a magnetar almost 30k light years away.
        94 million miles is a stroll in the park. A daily observation of both space weather and terrestrial weather will show how they are connected. As we approach Solar Max, with the new theories proposed since the last max to be tested, the new sources of data, and the theory of Dr. Henrik Svensmark on the connection between cosmic rays and cloud formation, the evidence is greatly increasing.

        We may find that the event/events that cause solar activity also cause terrestrial activity. The Sun may not be the cause. That theory may not be proven this cycle. We may have to wait until solar cycle #25… in 2150 😉

  31. Okay… been at this most of the afternoon.

    Again, mainly directed at Carl le Strange and Jack@Finland.

    First, one of the original plots of the SISZ area. This is a plot of energy release per longitudinal position along the SISZ. All quakes 1995 – 2011.

    Nothing is intended by marking the position of volcanic systems along this plot other than to give the viewer a frame of reference.

    http://i55.tinypic.com/2qd67x4.png

    Now… the same set of quakes as a function of what year they occurred. This is nothing more than a plot of the 12 hour quake count for the quakes in the above plot.

    http://i56.tinypic.com/2iifrpv.png

    This is the periodicity run to detect “psuedo-cycles” in the data from the quake rate plot.

    http://i55.tinypic.com/2by6bd.png

    10 noise runs were conducted using the mean and stdev for the quake rate plot. They are the gray dots.

    What is mean? Well, I don’t know. There appears to be a 252.5, 282, 299.5, 399.5 day signal somewhere in that mass of quakes. This could be a result of periodic large scale pulses of energy (stress-strain) that enter the Icelandic area from other parts of the two main plates and become manifest on the SISZ, or it could be anything.

    Again, I don’t know. I just thought it would be interesting to take note of.

    If you are confused now, welcome to the club. After all, I just plot stuff.

    1. Of those intervals that I pointed out, ≈282 to ≈286 seem to be the most significant… (provided that any of it is). Note that the over all trend of the points near that location rises against the generated sample noise points. It does this again at a 2x multiple up around ≈572 days.

      Again.. dunno what it is. I’m open to suggestions.

    3. Read briefly the paper, and found nothing spectacular. It seems similar results can be obtained by just picking all the data points in pairs and calculating the time difference. If there is any periodicity in the data it will be found out. Of course, if the data IS periodic (e.g. music), you’ll see strong peaks very nicely. The result will be the same, if you used ANY other method to reveal the priodicity (e.g. Fourier methods, etc.).

      Then to your plots. Let’s see what we really have there…

      The quake count vs. time plot is very enlightening. Major swarms once a year or so. Kind of leads to an educated guess with a weak periodicity around 200-400 days. Why weak? The daily average (about 10-30 quakes) is not very low if compared to the highest peaks (only 10-30 times more). And, the spikes are not truly periodic, they are actually sporadic.

      The last figure is very much like your another one from several months ago (I guess is was done with the Fourier method). Hence, they both seem to say the same thing: There are no truly periodic features. The fact that you get some spikes at X with a value of 30-50 just reflects the fact, that there were two major swarms with 200-600 quakes X days apart, nothing more.

      There is also another feature which adds support for the statement “nothing meaningful here, move on”. If you compare your “quake data periodicity” (red dots) with your “random data periodicity” (gray dots), you’ll see the peaks to not actually differ that much from the background noise in the last plot. Actually the peaks are only twice the noise. As the noise was one stdev, those peaks are only ~two stdevs. That is to say, very likely they are not real peaks with a meaningful physical explanation.

      If you were to find any true periodicity here, you’d be better to offer a physical explanation for it! Nature does not play periodically unless there a driving force for that with suitable bounds.

      So, what’s going on at SISZ? I think it is only the movement of the two plates. The strain in the area vs. the strength of the base rock vs. the relative movements are such, that on the average one major quake swarm occurs every year. “On average every year” does not mean it occurs e.g. during the same season. It only means, we get e.g. approx. 10 swarms in ten years, but not necessarily a swarm every year.

      Humans are just very eager to see patterns. because they think next about predicting based on that pattern. When there is no real pattern, the prediction of course fails. You’ll get just what you ordered!

      The first plot is very interesting, and I have enjoyed our discussions with Carl and you on this issue. I’ll let Carl comment it first as I have some more stuff to read on it…

    4. Lurking: Could you replot the first figure, but smooth it, e.g. with 2-3 km (one-tenth of Hekla to Torfajökull distance) running median?

      1. Thank you for your discussion on this.

        As for the replot, I have to go in and extract that data set again. I’m currently in the middle of smoking some Jalapeño, Serrano, and Habañero peppers on the grill so it will be later today (possibly) before I get it it.

        With the peppers I intend to prove a point. Chipotle was touted to me as “hottest of the hot” and I don’t think so. All it is are smoked Jalapeños. So… I’m treating a sample set to the same procedure to see who comes out on top. I’m saying the Habañeros. The Serranos are being done as a control group.

      2. Well, everything happens for a reason. There is no such thing as an accident. Sure, stuff can be outside your control, but there will always be an underlying reason(s) that things turn out the way that they do.

        In this case, I managed to get my data set more complete than it was.

        Back when Eyj erupted, I started doing data pulls off of the MET website and keeping the data in a spreadsheet. This got to be a pain in the arse after awhile. Go more than a couple of days and you get a large hole in the data. After finding the data in a flat file format on the SIL website, that eliminated the need to do periodic updates. I could just go pull down the weeks I was missing and be up to date.

        Then January 2011 came along.

        In the weekly SIL list, was a hole… about 2 days long. Week 52 of 2010 didn’t have it, and week 1 of 2011 didn’t have it. I figured that eventually that they would get around to correcting the problem and went about my merry way… and forgot about it. The only time I would think about it was in the long term plot constructions and think “oh yeah, theres that hole.”

        Today, while recreating the referenced plot, I decided to take a look to see if they ever filled in that hole. They did. So, now my data set is good… and I am a bit more pleased. Nothing really odd happened in the hole, so it was probably some clerical issue… and probably not very important.

        Anyway, here is the reconstructed plot, and a central point moving average of 55 points (in blue), that roughly equates to about 2.6 km.

        http://i55.tinypic.com/dq2ooz.png

        —

        Back to the odd-ball “psuedo-cycle” plots.

        I have been ruminating on the “spikiness” of those peaks. They didn’t exceed 3sd and they were very VERY narrow in nature. (single point above the rest). If there were some “resonant” phenomena at play, I would expect some width to be apparent in the spikes. The only part of the plot that has any width to the features, is in the baseline floor where the set as a whole trends upwards. It never climbs above 1sd, so its likely nothing more than an oddity, caused by the characteristics of the rock and settings… but not significant enough to stand up and be noticed.

        But… it was worth a shot anyway.

      3. Thank you! I though it should be enough to smooth out the ruggedness of the plot, revealing the general features (areas with higher release vs. more silent areas). Well, not quite to please my eye, but enough to see what I wanted to take a look at.

      5. Very interesting and revealing plot!

        The big quakes still have aftershocks in the same area. Hekla is silent, until she erupts. And the big quakes in 2001 changed the behavior at Hengill which I do find a bit peculiar.

  32. Thanks Lurking. I understand how this plot is put together now, kind of! Am I correct in thinking that if all activity should stop, this graph will also, and a new one will emerge when activity starts again?

    1. (Note to all, this refers to the SIL tensor plots and not that oddball collection of data that I have been making for Carl and Jack)

      No… the moment tensor plot will not stop, unless whoever is collecting the data decides to stop it for what ever reason. Either a new line of research, something significant happens, or for some other reason. It’s all dependent on who is making the plot for whatever reason. In this case, it’s to get an idea of how much seismic energy has been expended inside of an arbitrarily selected box. That is, “arbitrary” for the purpose of this response. Icelandic researchers have decided where the boundaries are at, and which areas belong to which volcanic system. They don’t follow the boundaries of the fissure swarm because that would a whole new level of uncertainty in the data analysis. Rectangles are easy to deal with and it’s easy to calculate the area. This value, the area, goes into determining just how intense the activity is there. (so and so much energy per unit area)

      A good way to visualize what the plot means, is to imagine that you have a balloon with a pressure gauge. You don’t know how big the balloon is, or how much it will hold. All you have is this gauge that tells you the amount that went in. You use that along with measuring the amount of expansion that you can see on one side of the balloon.

      Can you predict when it will go? Not really. But with experience you can get an idea of whether or not the balloon is in danger of popping.

      The plot is really straight forward and easily constructed. I can’t replicate it because SIL is using some knowledge of the systems that I can’t quite figure out. It could be the shear modulus of the rock, some effect dealing with pore pressure, or any number of variables that are unknown to me. I don’t pursue the matter because the whole purpose was to get an idea of what the systems around Katla were up to. Since they produce the plot, it would be a waste of effort for me to try and reproduce it. Plus, my plot would not be authoritative. (I’m not a Geologist).

      Hope this helps.

  33. You can not state that there is no connection between solar activity and siesmic activity, the science is undecided on it, you might want to read this page http://docs.google.com/viewer?a=v&q=cache:k5Hs_8ZKmd4J:arxiv.org/pdf/1012.3585+on+the+relation+between+solar+activity+and+seismicity&hl=en&gl=uk&pid=bl&srcid=ADGEESigQk3_h9oKpv8ew43kAdLYgdSMAjZQami5l768O1PyLdW28tGePLNShT1w7gRCnfBP7VgQv-4tU2fa5e6GAOFaOqddoYHnp_dTzGKVUj8M-cw0CWMRUWUtyhRSaVIL-_mzHhw2&sig=AHIEtbTfqkFVN8qhA4v6Vwd1Ygpbf6xTCQ

    1. @ Ben. Woooo…. Careful now!
      Thanks for the ongoing working hypothesis (proof), there is also a blog regarding all things stellar. Personally i do not think we live in a closed system and wave form energy comes in many frequencies, as well as the magnetic and gravitational forces that we have to endure from the great benefactor. Great bed time read for me, onward and upward.

      1. I think half the problem is that in searching for correlation, we attempt to identify instant recognition of corresponding data, as if effects were apparent immediately. With larger bodies and distances, let alone the myriad forces and vectors involved time lapses and delays are inevitable and patterns/cycles become less easy to see. More research!

    2. Bev Wallace says:
      September 10, 2011 at 01:59

      “You can not state that there is no connection between solar activity and siesmic activity”

      Oh yes I can.

      All USGS listed events Mag 4.5 or greater from Jan 1973 to Aug 2011 plotted against the Solar Flux.

      http://i52.tinypic.com/2vmx7km.png

      3. Wow looks like it actually goes the other way… low solar activity means more earthquakes, at least in the long term. Not sure about flares though.

    3. How about flares only? Some people get on the bandwagon of it being flares that cause the seismic activity and it not being the Solar Flux.

      Okay, here are the Flares for Solar Cycles 21, 22, and 23 vs the running daily worldwide quake count. (vertical scale is logarithmic, left is the Flare Strength, right is the quake count.)

      http://i54.tinypic.com/k2gryv.png

      That spike in the quake cound at 3/11/2011 is the Japan quake. I don’t have cycle 24’s flares on here because I am a bit tired and the Jim Beam is good.

      ‘yall have a good night.

      1. While I’m thinking of it, beware of reading too much into the daily quake count upwards trend. I call it technology skew. It happens because more detection gear gets placed into the field.

      2. “technology skew”… fact.
        Well done Mr Lurking, we now have a balanced conclusion to the solar flair/EQ discussion, there is no visible connection with flares on the plot.
        The only thing that is in the way of equilibrium now is people who add 2+2 and get 3 or 5 instead of 4.

    1. Now That is interesting Jon. … and I could imagine not very good for your eyes!
      What interests me is how far the ash is still capable of being blown even at such a low level. I wonder if it is volcanic ash that I see on some plants. I sometimes get a black sooty layer on broader leaved shrubs that I have tried to explain. It’s not due to aphids and happens rarely. I put it down to gunk from a local galvanising plant. But it is a mystery.

      1. The air here has been fairly dusty this summer, despite frequent rain. Suspect four causes: Grimsvotn (dark ash preceding the riots), local building works (light coloured dust), occasional Saharan sand and most recently the riots (soot from burnt cars & buildings).

      1. All the SIL station around Katla are showing a fairly big spike not sure exactly what this means at the moment..

    2. They are all unchecked and below 90%, so i think they will be lower in amount and size. The weekend is young, 🙂

    1. Not Krýsvík; seems to be near the geothermal plant at Hellisheiðarvirkjun. I cant tell if there is a volcano nearby – my searches have only pulled up a reference to a dormant volano somewhere in the vicinity.

      1. Did someone in a previous post suggest that such swarms can be man made and created by the pumping of cold water into the ground such as at geothermal plants.

      3. I think the earthquakes are manmade, but now they affected something on the volcano. They seem too deep. But they are happening exactly at the place of a how water station.

  39. These are predominantly deep earthquakes at @3 – 6km so it is more likely they are tectonic rather than manmade, although some are at shallower depths – I think we will have to wait for those more expert than I to take a look

  40. Hope this one is man made… as well as the others showing in Jón’s helicorder.
    08:46:02 64.064 -21.402 3.8 km 2.2 90.03 3.0 km N of Hellisheiðarvirkjun

  41. Thanks to those who gave auroracam sites yesterday – indescribable beauty!!
    Once again, thanks
    A

    1. Can anybody help me interpret the last part of these charts?
      This is AUST gps station, located on the northern rim of Katla caldera.

      http://strokkur.raunvis.hi.is/~sigrun/AUSTstutt.png

      What are the thin red lines? I guess specific volcanic events.
      In September something happened that made upward inflation increase suddenly and eastward deformation to invert trend. What happened there?

      By the way, the general inflating trend is quite noticeable.

  42. The swarm at Hellisheiðarvirkjun on the Reykjanes peninsula plot, looks intense.
    As I am looking none constrained from Friday 09.09.2011 11:02:26, I think it is probbably right on the plot though. This looks normal to me regarding the Reykjanes peninsula plot goes though I must say, what a place 🙄

  43. There was a clear harmonic tremor event in Katla just a couple of hours ago. You can see it in several stations like Lagu Hvolar or Skógar. But now it is over. It’s happening every Saturday due to the volcano burping gas after a heavy night of drinking.

  44. Active morning at both, Katla and Hengill
    Stærð Tími Gæði Staður
    2,5 10. sep. 07:11:08 90,1 1,7 km NNV af Hellisheiðarvirkjun
    2,4 10. sep. 05:21:25 90,1 3,9 km NNV af Hábungu
    2,3 09. sep. 21:32:31 61,8 5,9 km ANA af Goðabungu
    2,2 10. sep. 08:46:02 90,0 3,0 km N af Hellisheiðarvirkjun

  45. By comparing the Icelandic Meteorological Office Reykjanes Ridge map with Google maps, the swarm seems more centred on Hveragerði and according to Wikipedia, the surrounding area is part of the Hengill central volcano, and is geothermally active and experiences very frequent (usually minor) earthquakes.

    http://en.wikipedia.org/wiki/Hverager%C3%B0i

  46. I think the whole of the southern portion of Iceland was at Irpsit’s drinking party last night!!! 🙂
    Interesting swarm in the Hengil Volcanic system. I think that is where it is located .
    Carl will be interested in this one. It’s his “favourite” Volcano.
    Looks like being one of those Saturdays where I find lots of excuses to pop upstairs to check my PC . The family get a glazed look in their eyes when I start prattling on about volcanoes and earthquakes.
    The quakes are mostly quite deep. It is tempting to suggest this is magmatic. With boreholes and water being involved it is hard to assess and I will leave it with the experts. Katla in comparison seems less complicated! 🙂

    1. Diana:
      Soon they’ll start saying “what’s up with her? – something is wrong!”
      I know it from my own experience. 🙂

      1. My friends and relatives think I’m a crank for my interest in volquakes. You’d think that I had some sort of unsavoury hobby the way they carry on. 🙁 To make it worse my sister went on a diving holiday in Luzon earlier this year and climbed up to the lower lava flows on Mayon. It should have been me. *stamps feet*

  48. This is really picking up now isn’t it? I hope for your sake that this is just the norm, & not a further tell tale sign of an impending eruption!
    I wonder what she is going to do next!

      1. asm, hau and sau. They’re all showing some sort of alteration. Probably due to the swarm.

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