Posted on by Jón Frímann

Strong earthquake swarm on Reykjanes Ridge

Few moments ago (around 20:15 UTC) a strong earthquake swarm started on Reykjanes Ridge. This earthquake swarm is deep on the Reykjanes Ridge. Strongest earthquakes so far are ML3,1 on Reykjanes Ridge.

I am going to post updates as the swarm progresses. Some of the earthquakes can be seen on my webicoders here. But the distance is great so only strongest earthquakes are going to appear there.

Update at 21:06 UTC.

EMSC reports that the strongest earthquake was Mb4.8 while USGS is reporting that earthquake at Mb4.9 in size. The earthquake activity in this area is ongoing when this is written.

169 Replies to “Strong earthquake swarm on Reykjanes Ridge”

  1. Magnitude mb 4.7
    Region ICELAND REGION
    Date time 2010-10-23 20:38:31.2 UTC
    Location 63.58 N ; 23.11 W
    Depth 2 km
    Distances 85 km SW Reykjavík (pop 113,906 ; local time 20:38 2010-10-23)
    78 km SW Hafnarfjörður (pop 22,289 ; local time 20:38 2010-10-23)
    44 km SW Grindavík (pop 2,539 ; local time 20:38 2010-10-23)

  3. Upgraded: Magnitude mb 4.8
    Region ICELAND REGION
    Date time 2010-10-23 20:38:28.9 UTC
    Location 63.60 N ; 23.61 W
    Depth 2 km
    Distances 102 km SW Reykjavík (pop 113,906 ; local time 20:38 2010-10-23)
    96 km SW Hafnarfjörður (pop 22,289 ; local time 20:38 2010-10-23)
    63 km SW Grindavík (pop 2,539 ; local time 20:38 2010-10-23)

  4. I only took a quick nap! and looked what happened…watching EQ’s is like watching water boil turn your back for 1 second and you’ve missed it.

    1. There are volcanoes in this area. But they are more or less unknown due to there location. This does not look like a eruption event as it currently stands.

  8. A new large earthquake (Mb4.3 ?) did just happen at 21:59 UTC. It is clearly visible on my webicorders. It appears that IMO is currently underestimating the size of this earthquakes. The reason for that is a technical one. At least I think so.

  9. Magnitude mb 4.5
    Region ICELAND REGION
    Date time 2010-10-23 21:59:06.0 UTC
    Location 63.14 N ; 24.18 W
    Depth 60 km
    Distances 158 km SW Reykjavík (pop 113,906 ; local time 21:59 2010-10-23)
    150 km SW Hafnarfjörður (pop 22,289 ; local time 21:59 2010-10-23)
    117 km SW Grindavík (pop 2,539 ; local time 21:59 2010-10-23)

  10. USGS &EMSC are both showing these 4.5+ earthquakes – why isn’t the Icealndic site?

    1. It is a technical issue with IMO sensors. They are not really designed to estimate earthquakes this far away from them. So when a earthquakes that far away from them happens, the size is usually under-estimated.

      For that reason I relay on USGS and EMSC when this type of earthquake swarm happens.

    1. I did also record this swarm. This swarm and the Eyjafjallajökull earthquakes are the reason for 2000+ files for February folder on my earthquake monitoring computer. I am not done reviewing that few months later. Like so many other months after that. :/

  12. Yes but this is increasing: Saturday
    23.10.2010 22:14:59 63.457 -23.975 1.1 km 2.3 59.94 9.2 km WSW of Eldeyjarboði
    Saturday
    23.10.2010 22:09:47 63.432 -24.060 12.6 km 3.4 53.21 14.2 km WSW of Eldeyjarboði
    Saturday
    23.10.2010 21:58:28 63.335 -23.986 1.1 km 3.1 86.26 19.4 km SSW of Eldeyjarboði

    1. What did I say yesterday
      I had a feeling you were correct
      the only cam I can find is the Imagine Peace Cam

  16. upgrated: Magnitude mb 4.6
    Region ICELAND REGION
    Date time 2010-10-23 21:58:57.7 UTC
    Location 63.37 N ; 23.88 W
    Depth 2 km
    Distances 129 km SW Reykjavík (pop 113,906 ; local time 21:58 2010-10-23)
    122 km SW Hafnarfjörður (pop 22,289 ; local time 21:58 2010-10-23)
    89 km SW Grindavík (pop 2,539 ; local time 21:58 2010-10-23)

  17. OK, Raving, not unique. But that’s the way it goes. It will continue to the North and in my very, very amateur view this will reflect in volcanism either in Mýrdal or Vatnajökull.

  18. Somebody wake Lurking!
    Most of them at shallow depths. Was that 60 km a right figure?

  19. EQs all over the world: Kenya, Greece, Chile, Japan, Philippines, Alaska and now Iceland… This cannot be mere coincidence. There is an explanation, which we don’t know.

      1. I understand your concern, Jón, and you are right. I don’t mean a doomsday scenario over this, but just that those things sort of come in waves, which could be perfectly normal. We just cannot explain why they happen in waves. Sholz’s pendulum effect? 😉

      2. Humans have a strong inherent tendency to see “reason” everywhere. Seeing “connections”, when there is none, is one very good example of it.

    1. It happens because of weather, ocean movement (waves) and now the spikes are due to the earthquake swarm on the Reykjanes Ridge.

      It means nothing else then what we are currently seeing.

  22. Except for the spikes, Reykjanes tremor graphs are pretty steady. But IMO is still shy about the magnitudes…

  23. Global Magnitude 7.0-7.9 quakes are up 90% in 2010
    http://modernsurvivalblog.com/earthquakes/mag-7-earthquakes-are-up-90-percent/

    Magnitude 8 – 9.9
    2010 Earthquakes so far (1)
    annual average (1)
    100% of 100yr. annual avg. to day #293

    Magnitude 7 – 7.9
    2010 Earthquakes so far (19)
    annual average (15)
    158% of 100yr. annual avg. to day #293

    Magnitude 6 – 6.9
    2010 Earthquakes so far (134)
    annual average (134)
    125% of 100yr. annual avg. to day #293

    Magnitude 5 – 5.9
    2010 Earthquakes so far (1,459)
    annual average (1,319)
    138% of 100yr. annual avg. to day #293

    Why? Solar Minimum perhaps?

    Increase in seismic activity could also trigger an increase in volcanic activity

    During the Little Ice Age volcanic activity was much higher compared to the past century. Joseph D’Aleo states that we are in a phase of more frequent volcanic activity.
    What’s the statistics on volcanism?
    The weelky updates from SI USGS don’t provide us with a complete global picture let alone an oversight global volcanic emissions and events.
    http://volcanism.wordpress.com/2010/10/14/siusgs-weekly-volcanic-activity-report-6-12-october-2010/

    Anyhow, the Little Ice Age, the Maunder- and Dalton Minimum coincided with
    solar minimum, colder climate and a high frequency in volcanic activity.

    I really wonder if these observations from the past provide us with an indication for
    the near future.

    1. The answer is no. See here, http://www.consrv.ca.gov/index/Earthquakes/Pages/qh_earthquakes_myths.aspx

      “Earthquakes are becoming more frequent. Research shows that earthquakes of magnitude 7.0 or greater have remained fairly constant throughout the century and have actually decreased in recent years. However, since there are a greater number of seismological centers and instruments capable of locating many small earthquakes that went undetected in earlier years, it may seem as if there are more.”

      I also want to point you to this post I made today about myths and other types of nonsense, http://icelandgeology.net/?p=133

      1. R. de Haan: We tend to desire that such cataclysmic events should happen within our short lifetime span. It sort of gives us the feeling of our “importance” as the “chosen ones”, I mean, those who are the lucky ones to witness such important events. Well, sorry to say, we aren’t. I’m pretty happy to have witnessed Eyjafjallajökull the way I did: knowledgeable people, like Jón, Erik and Boris providing us with precious information; friendly fellow bloggers with their eyes wide open to any changes, links and news; live cams placed at the right place at the right moment, and even better, to know it didn’t cause any large scale tragedy for the warm Icelandic people.
        I’m very cautious when I place a comment like the ones I did above, which are result of sheer speculation of an amateur. I don’t believe EQ activity has risen in a wider scale, I don’t believe sun and moon could respond for any changes in such “earthquake waves”, at least no scientific evidence to support it. But I do sense there is a tendency for EQs to oscillate in a wave basis, yet I could be totally wrong.
        It was a joke when I said my “forecast” was “right” because yesterday I said a swarm was coming. Probably I was in a lucky mood when I posted it. I said many stupidities before, and this was yet another one, only that a swarm did indeed occur.
        And I will stretch my luck a little further guessing that this activity will be moving further North. And if it does, (I don’t really “believe” it will), I leave for the scientists the task for further research.
        Jón, thank you very much for the opportunity we are having to share this space and get to learn more.

      2. “Earthquakes are becoming more frequent. Research shows that earthquakes of magnitude 7.0 or greater have remained fairly constant … , it may seem as if there are more.”

        I also want to point you to this post I made today about myths and other types of nonsense

        Strangely, as the way this reads .. it is as if you are metaphorically describing the AGW temperature record debate and also embracing the added peculiarity of NASA devising and launching every sensor imaginable to prove investigate the myth trend.

        How to Lie with Statistics is sorely in need of a revision to keep current with recent developments in “Trend Analysis”.

        No wonder Lurking is flying happier than a …

    2. Square root of 15 is approx. 4, so the number of annual quakes in magnitude range 7.0 – 7.9 will naturally vary in range 11-19 per year for 70% of all years, i.e. nearly all the time. So, even if the difference in percentage is significant, the real difference in occurrence is just plain normal. Got it?

  24. @Jón Frímann…

    Dude. Your blog kicks arse. (BOSEG!!!) I spend the better part of the afternoon running around looking for a nice stout box to ship a couple of routers and six laptops in and I come back to see that your carrying on a battle with the alarmism junkies. And.. on top of that, Iceland has decided to weigh in with a rather significant MAR quake.

    Who could ask for a better Saturday afternoon?

    1st, I would like to point out, that Arkansas and the Central US had a few out of the ordinary large quakes here a couple of weeks ago… and Little Rock (the capital) didn’t go “poof,” so….

    Magnitude 7.0+ quakes happen from time to time. As Jón has pointed out, (I paraphrase) ‘aint nothing but a thing.’

    Lets look at the real data if anyone cares to doubt this. Data source, USGS website, wordwide quakes, Mag 7.0 and up. Binned quake count with a 180 day window.

    http://i51.tinypic.com/2dumc20.png

    Don’t believe it? Go pull the data yourself. 2010 is on a par with the higher counts occurring ≈ 1990, but do keep in mind that a couple of the biggies this year turned out to be two or more large quakes that were so closely related in time that their waveforms were mixed, and it only became apparent that there were two events from later analysis.

    That data set goes back to 1973, so let’s take a closer look at it. (This is one of my favorite plots.) This is a plot of the AVERAGE number of days from a large quake, until the the next same sized or larger quake. Since this is an average, let’s toss in the sigma, or standard deviation so that we can get a better feel for how accurate that plot is. Note the green line, that’s the sigma. In other words, how many days before or after that average date that they tend to occur.

    http://i51.tinypic.com/ok8is1.png

    I do have to admit that above Mag 8.2 the plot gets squirrely since there are so few events to work with. But if you note, there does seem to be a nice growth curve to the data.

    Now, what I really wanted to plot before this doom and gloom stuff came along.

    This is a plot of southern Iceland for the last 10 days… up to and including that Fandango over on the Reykjanes ridge, enjoy.

    http://i54.tinypic.com/30hswo1.png

    1. Then it was less then Mb4.5 that is needed to get into USGS and EMSC web page. It also doesn’t show clearly on my webicorders. But as you can see now, larger earthquake do appear clearly on my webicorder.

      1. Raving: It looks different from time to time, how could one possibly “fake” it?

      2. For one thing, the refresh time is in multiple minutes but the time displayed on the web page increments by the minute. That is enough to put me off it. I feel mislead.

      3. Well, yes, since you say it. It kind of “looks” fake. But I have never seen an aurora, and they always seemed to me too beautiful and too impossible to be real…

      4. Renato Rio says:

        …they always seemed to me too beautiful and too impossible to be real…

        There is light pollution, image enhancement and even some evidence that earthquakes can trigger aurora discharge.

        But the theory I like is best is described on the night They Cremated Sam McGee

      5. “The Northern Lights have seen queer sights…”
        This is beautiful.
        Thanks for this way to look at what it will become of us all.

      7. And when the aurora is strong enough (which it surely was last night), you can see it even on a webcam. I have photos from the same side, where you can see the aurora in front of the “light tower”. Unfortunately I missed this last night.

    1. I wonder if this is a true swarm or was the 4.8 the main shock. I can’t tell the sequence. Of course, there is a %5 chance these are preshocks to a larger quake as well. Well, anyway, its all relative..at least thats what my Aunts and Uncles say.

  30. Jón, it looks so. But IMO never reviewed the mag 4+ on the tables.
    And now Grmsvötn seems to get the echoes of this. (I know, just kidding). But the quakes are there. And none at Esjufjöll. This is all rather confusing.

  31. Jon, I have been reading several articles about this. If this body of theory starts to carry more weight, this is the reason So Calif is so potentially dangerous right now in the next decade + as there are several faults adjacent to each other than suspected to be at the end of their loading phase including the San Andreas Fault (SAF). This would be the San Jacinto Fault, Elsinore Fault, Barstow Fault and San Andreas Fault. A cascade of faults breaks there would be very catastrophic to Calif and the U.S. if they start in the next several years as things are economically fragile in Calif and the U.S. Most seismologists that study the SAF agree that has a 99.9 chance of breaking in the next 30 years as it is overdue now. If this happens in the next 2-3 during this tenuous time, Not Good.

    I will try to find the articles I have been reading about the concern that the Barstow and SAF would trigger each other and post it here.

    Hope you don’t mind the side topic if its only spartan.

  32. Ref: RonF [05:07]

    Don’t forget the other blocks. San Clemente fault, Thirty Mile Bank fault, San Diego Trough fault zone, Coronado Bank fault zone, and the Newport-Inglewood – Rose Canyon fault zone that snakes down through Langley field (the airport) and branches off into a myriad of faults through San Diego bay and the Silver Strand.

    They all mark off roughly parallel blocks to the ones bordered by the Elsinore, San Jacinto and San Andreas.

    Being smaller blocks, I would imagine that they would have less staying power and be more prone to creaking. That cluster of quakes at 31° 21.498’N – 116° 3.684’W might be more in line with an unknown extension of one of those faults from offshore.

  33. @ Renato Rio, “Just about in time”

    Eh? For what? My plots are not predictive in nature. I’ve never claimed that they were. I make them in order to get an idea of what is going on. Sort of a reality check of what we are seeing despite the murky view we ordinarily get from boring lists, yammering and alarmism that tries to pass as the real deal.

    I may have been a bit late in getting a plot out, but I had been fiddling with volcano outlines in shp file format (something not readily available, so I had to make my own) and had to sit down and eat the time sink of redrawing the outlines and converting them to Mercator projection.

    Eh.. no biggie, I plot therefore I am.

    So, along the same idea of getting a clearer picture, a tidbit from “Global Techtonics, 3rd ed” pp 133 Keary (deceased) , Klepeis and Vine. Wiley-Blackwell Publishing.

    “…This study was deliberately centered on a magmatically active axial volcanic ridge (AVR) on the Reykjanes Ridge at 57°45′N, and did reveal a melt lens and crystal mush zone analogous to those imaged on the East Pacific Rise. In this instance the melt lens occurs at a depth 2.5 km beneath the sea floor. The results of this study provide strong support for the hypothesis that the process of crustal accretion on slow-spreading ridges is analogous to that at fast-spreading ridges but that the magma chambers involved are shortlived rather than steady state. Despite its proximity to the Iceland hot spot, the ridge crest south of 58°N on the Reykjanes Ridge has the characteristics of a typical slow-spreading ridge: a median valley, and normal crustal thickness and depth…”

    Bold added by me.

    The area referred in the text is about 557 km south of where these quakes occurred at. (≈300 nm).

    Looking at the group of quakes end on, looking North East up the Axis you get sort of a profile view of the spreading center and where the quakes were at. The boundaries of this box were cropped in to exclude the quake stacks that you see closer to land. (they would just interfere with being able to see the spatial relationship of the quakes)

    http://i56.tinypic.com/34ff8ux.png

    Enjoy.

  34. Sort of an afterthought. The MAR in the vicinity of the Reykjanes Ridge spreads at about 20 mm/yr. Per figure 6.3 on pg 124 of the previous document, that places this area on the lower end of “slow spreading” ridges, and generally has a seismic depth of up to just under 8 km.

    As you can see from the quakes, the operative word there is “generally.”

    A comparison of my axial view plot with part of Figure 6.11 (slow spreading ridge cross section) you can see a similar pattern in the way that the terrain usually faults as it cools and moves away from the center. These grabens seem to be a common feature of slow spreading ridges.

    http://i55.tinypic.com/2mg2gro.jpg

  35. Sunday 24th October 2010
    Merapi Volcano, Indonesia
    Since Merapi volcano was upgraded to level 3 alert on 21st October, the volcano has showed increasing activity. All monitoring methods such as deformation, seismology and gas emissions have indicated an eruption is imminent. There is an exclusion zone of 8 km around the volcano. Tourists are forbidden to climb the volcano.
    More on Merapi volcano…
    http://www.volcanolive.com/news.html

    1. Where do you see that, Renato?
      I’m just the last half hour looking at the websites and camera’s, but the status is still “alert”.
      There is nothing to see, as it is night there and the weather is not good.

      1. Sorry! Wrong translation: “Official warns of eruption” – I understood that it is now official.
        However, they admit that lava was seen but they’d rather not confirm it because the source is not official.
        Thanks, Starwoman.

  37. Sunday 24th October 2010
    Piton de la Fournaise Volcano, Reunion
    Eruption at Piton de la Fournaise volcano is stable. There has been no new injection of magma into the system. Lava continues to flow towards the southeast. A significant decrease in the emission rates of magmatic gases has been recorded. Volcanic tremor is lower than at the beginning of the eruption.
    http://www.volcanolive.com/news.html

  40. The swarm looks like a possible eruption event. So I would not be surprised to hear about an undersea eruption in the near future.

  41. “On Thursday, the volcanic cone was observed to be expanding by 8.5 centimeters a day, while on Friday the rate had picked up to 16.4 centimeters a day.

    “Sri Sumarti, the Merapi section head at the Volcano Investigation and Technology Development Institution (BPPTK), said… … there were two types of eruption, the first a Pelean eruption that has a pyroclastic flow with lava streams. The second is a Plinian or Vesuvian eruption, which is far more explosive, throwing ash and rock more than 25 kilometers into the atmosphere, but does not always have a pyroclastic flow. “Whichever we get, we must prepare for the worst,”

    It is highly unusual for a professional vulcanologist to make such an emphatic statement…

  42. Yes i agree… indonesian volcanos are very dangerous, they are preparing for an explosive eruption!

  43. Is there another webcam focused on Merapi? The Volcano Live webcam appears to have gone down in the last few minutes – either that or there is suddenly a lot of smoke obscuring the view.

    1. Back up now – looks very strange, all of a sudden the peak of the volcano is completely covered in smoke – or else it’s gone. Sorry for going off topic.

      1. It has been covered with clouds several times tonight, so it does not have to be smoke.

  44. Hey guys – lets keep the non-Icelandic comments and posts over at Big Think Eruptions or where you wish – this blog is Jón Frimann’s blog for things Icelandic, no???? If something big happens outside of Iceland, (Merapi etc.) make a referral to Eruptions and carry on over there…please?

  45. Jón, do you have an email contact listed somewhere on one of your websites? Or can you mail one to me at my mail which should be listed somewhere with my registration, please?

  46. Iceland quite often has some powerful earthquakes around the Reykjanes ridge and peninsula. There was some two 6.0 in 2000 and 2008, that even damaged some houses in Hverargerdi and Reykjavik, no?
    That peninsula has a lot of tectonic activity!

  47. Jon, doesn’t look interesting that this week we saw a significant increase in earthquake and volcano activity all around the world? I understand your reply that ‘this is a coincidence’, which is expected from someone with a scientific background.
    However, I think it is also scientific to challenge status quo theories, to ask \what if\, even ones that we think are well established. This is just part of good science.

    So I ask what if there is some mechanism on the magma or even at the planet’s core, that provokes such a global wave of earthquakes and volcanic activity. We cannot simply dismiss that hypothesis as impossible. It shouldn’t be just because we have no explanation, that we don’t consider challenging an existent scientific model. The revolution that Physics, Astronomy or Biology suffered during the past decades is just one lesson. To the utmost important to keep an open minded attitude to possibly uncover new and better scientific explanations.

    I think geologist have bias towards considering geological connections when linking for example Katla and Eyjafjallajökull, but not Katla with Grimsvotn, Reykjanes with Krafla, or Reykjanes with Azores. It is only a question of perspective. Humans have a bias to assume their models accordingly to their size. We just think a volcano here cannot be linked to a volcano some thousands of km away. But the planet is one. We know for example, that solar activity increases and decreases as a whole in the entire sun surface. Why cannot volcanoes do the same on Earth???? What if they do?

    3. “this week we saw a significant increase in earthquake and volcano activity all around the world”

      Was there an increase, and why was it significant?

    4. It’s very interesting you stablish a relationship between Azores and Reikjanes because Azores are very active in the last days and just now have this one: Magnitude ML 3.4
      Region AZORES ISLANDS, PORTUGAL
      Date time 2010-10-25 09:38:02.0 UTC
      Location 39.58 N ; 29.72 W
      Depth 10 km
      Distances 1742 km NW San cristóbal de la laguna (pop 139,928 ; local time 10:38 2010-10-25)
      239 km NW Angra (pop 12,045 ; local time 09:38 2010-10-25)
      148 km NW Ribeira grande (pop 5,198 ; local time 09:38 2010-10-25)

  48. Hi Jón, I did try to send to the email as it is in your message, jon…@ and also without any dots, jon@ – both were returned. The link as posted does not work. Any suggestions?

  49. It will be interesting to see if the swarm will completely stop or will go on for a while. If I remember right, and this does not necessarily have a connection with the Eyjaf erpuption, there was a swarm on Reykjanes before the quakes started on Eyjaf. I thought it was sort of curious that it went that way. Just something I noticed as a coincidence, though at the time, I thought they were connected.

    OT @Renato, the Aurora can be absolutley beautiful and mysterious. The first time I saw it was when I was in N Dak. It was white and it went from east to west and over the top of what I call he bowl of the sky. And one night, about 10-12 years ago, we could see the Aurora clear down here in CA! It was a beautiful dark pink color. Now that was really something to see.

    1. This year has been great for auroras even into the middle latitudes. I have a few great pics I’ll post if I can find them. Really do check out the site I posted its awesome. Thank you Renee

      1. Thanks for the descriptions of auroras. They really intrigue me and they are so beautiful!

    1. Henry: I have seen what I think was a light house at this spot where the red glows are. At night you can see a white light that keeps coming and going, but a white one.
      Anyone have noticed that the webcam at Reykjavík shows a semi frozen lake? Swans and ducks are “walking” their ways, instead of swimming. Cool!

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