Watching Hekla

Kobba informed us that the alert level at Hekla was raised to yellow:
http://www.dv.is/frettir/2013/3/26/ovissustig-vegna-jardhraeringa-i-heklu/
Some things are up with Hekla….Alert levels raised to yellow due to “peculiar unrest” in Hekla”

“Translated: National Commissioner of Police and the Commissioner of Hvolsvöllur declare confidence level of civil eruptions of Hekla

The Icelandic Meteorological Office has informed the National Commissioner for Civil unusual Seismicity at Hekla. IMO has also increased monitoring points Hekla to yellow due to air traffic, which means that the volcano show unusual activity.

Uncertainty level civil means for increased monitoring of the actions of that at a later stage could lead to health and human safety, environmental or building will be threatened. To describe the level of uncertainty is part of the processes in the organization of civil protection to ensure formal communication and information. Uncertainty level is declared to inform the appropriate emergency and is a process in civil emergency planning and the lowest of the three.

In light of this, will the National Police Commissioner and the Commissioner of Hvolsvöllur warn people on journeys while Hekla uncertainty level is valid.”

http://www.ruv.is/hekla Image taken on March 18th.

Erik Klemetti has the news too on his blog Eruptions. Alert Status Raised at Iceland’s Hekla

Icelanders photo as the staff

Icelanders photo

Icelander: “VC staff photographer has sent us this test image. Expect more of it in action, whenever that will be. Enjoy. http://i50.tinypic.com/2e5v5ax.jpg

Yes, these were for express use of VC and be used when Hekla became “imminent” :-) Copyright lies with the photographer. Here is another angle from October last year.
http://i49.tinypic.com/1z9jsw.jpg ”

Here are plots by chryphia of Hekla´s local earthquakes from 2000 until today.

Hekla seismicity 2000 to 2013. View from NE. The bulk of blue events occured on the day of the last eruption Feb 26, 2000.

Hekla seismicity 2000 to 2013

The last two earthquakes from the listi were on Mar 21st and 23rd and were located in the small group at 10 km depth:

Hekla seismicity 2000 to 2013

Hekla seismicity 2000 to 2013, view facing West. The depth axis is compressed about 2x in order to get the Moho layer (http://www.seismo.helsinki.fi/mohomap/) into view. The topology is from geodas-design-a-grid.


Icelanders image and his explanations: Quote: “for these watching IMO uncorrected strain charts – this is how they appeared in April 2012, the month I thought it whould go off, so nearly 12 months old.
Notice the large drops at HEK (other stations were not operating then). Graph is stretched or schrunk, to get “same unit scale” (a feature or the Original IMO charts I do not like, is that their scale is NOT constant, but fortunately they are scaled, so here goes). http://i45.tinypic.com/ziopkw.jpg
Yess, top graph is BUR, same days as HEK (lower). I have the days before these too. Including a big quake of international standards, first a meeting, then more plots (Yes these are mine “Scale-ings”!)”

Remember Carl wrote a lot of posts on Hekla, you can find them here.
Spica

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525 thoughts on “Watching Hekla

  1. @ TGMccoy

    Whidbey Island (Washington State) had a landslide. Best I can figure, it was on the west end of the island. According to “news” reports, no heavy rains where involved.

    To me… (untrained in geology) that would mean that the overall tilt of the land had gotten to the point where the bluff became unstable.

    In my opinion, it points at the huge amount of energy being stored up and that is flexing the crust… until the Cascadia lets go and releases the energy.

    It is highly likely that your move inland was quite prescient.

    • Umm… “eek?”

      Just read a post by someone who lives on Lake Whatcom who is alarmed by the water level dropping noticeably over the course of an hour. No idea how much, no idea exactly where… but the lake is east of Whidbey Island and it could be a manifestation of that flexing crust idea…

      • THAT is more concerning than the land slide. it is mostly sandy/volcanic soil
        but, there isn’t much of a history of that area sliding like the Troutdale formation
        in the Portland Vancouver area that thing bites every once in while. Also the NW hasn’t had that much rain.. Hmmm..

    • I saw this on the news this morning. There was film of the people frantically removing their possessions from those homes in danger.

    • Considering that this is on the coast, it easily could just be a product of gradual erosion weathering away the face of the cliff. But that’s just a guess without knowing much about the background of the area or the situation.

      • To a point, I agree. But the area has not had a remarkable amount of rain to prompt this sort of event. When soil becomes more laden with water than what it can support, you usually get a slide. The sheer face of that bluff testifies to it’s tendency to fail. I think flexure caused this section to exceed it’s ability to stay intact.

        We know that megathrust quakes are amplified by the relaxation of the overriding plate once the stress release starts. The region of Whidbey Island sits on that overriding plate… as does that lake to the east.

        The interesting part about the whole affair, is that reportedly the lake returned to what appeared to be normal levels on short order. Was there a slow-slip aseismic event that relieved the stress? They have been studying this region up and down the coast and registering non-quaking tremor events.

    • @ Luisport

      Yes, it will be interesting to look at what she’s up to between 4.45 pm- 5.45pm today.

      Of course, strain may also start to trend the other way instead!!

      Who knows….

  2. Currently the net is frustratingly slow due to some kind of spamwar going ón in Europe between two email service companies! Childish BS to no avail, slowing normal traffic and scoring absolutely no good Will for Amy of the combattants.
    Just a sour note ón an otherwise interesting Day!!
    Happy volcanowatching all of you!!!

    • going by others it would have to be 3.7 more likely, HT and larger EQ started around 5.20 to 6.10, seems to settle down again

  3. I awake to see another burst of earthquakes on El Hierro, starting with a 3.4 at 16.6km at 5:19am, but followed by many more large quakes which are still ongoing. An uneasy day ahead for the residents.

  4. 1201525 28/03/2013 06:05:52 27.7242 -18.2451 19 3.3 mbLg W FRONTERA.IHI
    1201534 28/03/2013 05:45:24 27.7428 -18.2492 19 3.1 mbLg W FRONTERA.IHI 1201524 28/03/2013 05:39:56 27.7460 -18.2555 18 3.1 mbLg W FRONTERA.IHI
    1201535 28/03/2013 05:23:58 27.7500 -18.2593 17 3.1 mbLg W FRONTERA.IHI
    201536 28/03/2013 05:28:08 27.7422 -18.2178 17 3.3 mbLg W FRONTERA.IHI
    1201533 28/03/2013 05:22:34 27.7717 -18.2659 17 3.2 mbLg W FRONTERA.IHI
    1201522 28/03/2013 05:19:55 27.7598 -18.2917 17 3.4 mbLg FRONTERA W.IHI

      • Not compared to these data, but they are a lot deeper than yesterday.

        On the other hand, a deep feeder in the 1-2 Hz is still missing.

        • Another paywalled paper that somebody might be able to do something with. I was googling for images of the crust under El Hierro and found this chart of the magnetic anomaly in the paper:

          Source paper:
          Estimating the magnetization direction of crustal structures by means of an equivalent source algorithm
          from Nicolosi, Blanco-Montenegro (great name: Mrs. White-Mount Black) et al.

        • Yes, Inge, I noticed the increased depth of today’s quakes too. Are they still going South? I have to go out so haven’t time to check.

        • Found another nice illustration from Earthquake Report explaining the Restingolites (was that how we used to spell it… I thought they were restolingas.. hmm)

  5. Pingback: El Hierros´western part on “Code Yellow”. | volcanocafe

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