El Hierro still going strong and a riddle

Some parts (?) of El Hierro experienced a short power outage last night, This was also viewable on the solitary working webcam at the moment which was noticed by some regulars. Quite some earthquakes Mag. 3+ and even some Mag 4+ have been recorded.
CJUL_2013-03-29

chryphia created a new plot which shows the action going on:

Quote:” Here is another 3D plot, no overlays this time ;-).
It shows the current swarm and the older earthquakes in two separate color scales. I wanted to see where the central El Golfo bay earthquakes are located exactly: they are slap-bang in the middle of the northernmost, deep (magenta) swarm, barely visible in this plot. This is where all the other swarms originated, thus I am worried that there is even more magma arriving now. For a good 2D view look at http://www.01.ign.es/ign/resources/volcanologia/html/eventosHierro.html

Earthquake Report has a link to an image of all the spectrograms of this crisis stitched together: http://jdcv.es/Media/Hierro/2013/CHIE_upto2903_B.jpg
from http://earthquake-report.com/2011/09/25/el-hierro-canary-islands-spain-volcanic-risk-alert-increased-to-yellow/
Noted by Jim Ludwell.

Earthquake-report.com also used chryphias plot without giving her credit which I personally find absolutely not OK.

Many can explain the current crisis much better than I ever could. So here there are some comments to good to be lost:

GeoLurking says: March 29, 2013 at 04:37
Quote: “when this whole thing was first bopping along, the gov was reticent about doing anything until it became clear that Mag 4.0 quakes were a possibility. Mag 4.0 was where they flinched and it was clear that something could shake loose and hurt somebody, so that was about when they started taking precautions.

One thing that Carl noted was that the seismic gear was probably not set up for volcano monitoring and that IGN and Pevloca had to undergo a paradigm shift from watching for potential landslides to watching for volcanic activity. Outside experts were consulted and new gear was brought in. (the temporary seismic stations and the additional GPS units.)

Now 4.0s seem to be regular fare. It doesn’t lessen the hazard. A 4.0 still releases considerably more energy than a 3.0.
For now, the most immediate threat is still the same. Something getting shaken loose from the bluffs.

Then there is how it plays in the volcano scheme of things. If the quakes are being caused by magma forcing it’s way through the rock, the best that I can envision is a series of normal mode faults. A 3.0 has a maximum displacement of 0.275cm. A 4.0 has 1.17cm. That’s would be a crack about 4.3 times the size of the 3.0. Keep in mind that this is probably pushing the Wells-Coppersmith equations a bit outside of what they were intended for, but it does illustrate the differences in the two quake sizes.

If it is magma pushing through rock, what has happened is that the hoop stress of the rock around the area of the magma has been exceeded and the magma breaks open the rock with what is probably a mode 1 crack. This realm of math is beyond me, so I rely on the Wells-Coppersmith crutch to provide some level of understanding. Going whole hog, and looking at the rest of the formula… a normal mode fault of Mag 4.0 has a down dip rupture width of 1.82 km. If intruding magma is what is at play, it could conceivably make a path about half of that width higher each time it happens. If that starts to show up in the quakes…

Read the whole comment by clicking it.

Renato Rio says: March 29, 2013 at 13:34
Quote: “The PEVOLCA maintains civil protection measures in El Hierro and follows the evolution of the phenomenon
03/29/2013 … 12:38 – Ministry of Economy, Finance and Security
* The data indicate that the seismicity has migrated to the southwest in the last 24 hours. The direction of the Civil Protection Plan for Volcanic Risk (PEVOLCA) maintains civil protection measures that were taken last Wednesday in El Hierro given the magnitude of the seismicity that is occurring to the west of the island.
As you may recall the steps taken by the management of PEVOLCA are the following:
Disabled the lane closest to the on the output side of Frontera tunnel closing the stretch of road between the HI 50 between Cruce de la Tabla and Sabinosa and the access road to the Playa La Madera, the Pozo de la Salud to the confluence with the HI 503. It is important to avoid transit through these areas because of the risk of landslides.
Accesses are opened to the Ermida de los Reyes and the southern Sabinar area, HI 400
Meanwhile it is maintained the yellow alert of information to the population in the area bounded by the HI 500 and the height of the Pozo de la Salud to the south, at the confluence of the HI HI 500 with 400 in the crossroads known as El Tomillar.
As for the seismo-volcanic phenomena, earthquakes located in the last 24 hours have migrated slightly to the southwest over previous days, reaching the west of Orchilla between 15 and 20 kilometers deep at a distance from the coast between 12 and 15 kilometers. The values ​​of CO2 in the atmosphere have increased but are still within normal parameters.
The direction of PEVOLCA wants to remind you that they are doing continuous monitoring and real-time of thr phenomenon, so any change in the pattern of movements that imply risk will be communicated immediately. It also recommends considering the advice of self-protection in the event of earthquakes, known to all, and can be viewed in http://www.gobiernodecanarias.org/dgse/descargas/sismo_hierro/autop_sismo.pdf

Bruce Stout did some drawings:
BruceTo understand the images one needs to read Bruce’s comment and all the follow up’s by Peter Cobbold and Bruce. Bruce Stout says: March 29, 2013 at 14:23

Richie Lee gave us a link to a TV station in the Canary islands where some news might be broadcasted. Canary TV: They don’t stream everything but most live newscasts are available. The last few days they have had coverage of the El Hierro activity.

http://www.rtvc.es/television/enDirecto.aspx?canal=tv

I personally do not think any eruption is imminent, but it is interesting to watch. And in case you need the links again, just holler.

Spica

———————————————————————————–

A riddle for tonight, while we are watching what is happening in El Hierro and Iceland!
Same as last week …. so link the each clue to a volcano and spot the red herring ….

1 point for each volcano and 1 point for each red herring (with brief explanation)

All solved … Red herrings in bold … Answers ..

No 1 Big Ben

No 2 Mount Churchill

No 3 Hekla

No 4 Glen Coe

No 1 – 2745; Furious 50s; New York landmark; Augustus Pugin; SOLVED
No 2 – Bobsleigh run; Radiocarbon; Battle of Stepney; Infantry Tank; SOLVED
No 3 – 1750; 1104; 1864; 4892; SOLVED
No 4 – 1692; Easter Island; Cauldron subsidence; Harry Potter; SOLVED

Points .. Well done all

Kelda  4 points

Volcanic 2 points

Stephanie Alice Halford 1 point

Inge B 1 point

Kilgharrah

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327 thoughts on “El Hierro still going strong and a riddle

    • Slight ? Barely any. Note: we are waiting for approimately 300,000 units or more, not 1,000 – and this is not clean drop, only a irregularity. 🙂

    • I might add: then we look for quakes, then we look for tremour, all three in place we can (but not certain) be having a runup, lasting from 30 to 90 minutes, However, I think it starts with tremour and quakes, then strain falls in last 30 min before it blows.
      *not expert* 🙂

    • The one thing about Hekla that I am pretty sure of. When it’s time, Hekla will not pussyfoot around about it. It will be decisive and there will be no question about what it’s doing.

      • Better not. This fluor content of her ash is really unhealthy!
        “At Hekla, soluble fluorine adheres to erupted tephra particles, leading to lethal fluorosis in grazing animals even in areas of minor tephra fallout (Óskarsson, 1980)” cited in Freysteinn Sigmundsson, etal.: Natural Hazards in Nordic countries, (2008) p. 176

        And given the fact, that m o s t animals are grazing outside, that would mean that a lot of horses and sheep would die and farmers be ruined – if she really goes “boom”. Also drinking water could be affected.

        I am more for a small effusive “tourist eruption”.

        • Also the south of Iceland is the part of the country, where most of the vegetables and corn comes from – this could also be contaminated..

          • It does not pollute these, the fluoride washes away very soon, only acculating in sheep and horses thrugh eating the grass while its poisunous. 🙂

  1. the graph is running fine a bid short and quieter now, catching its breath after all the excitement, it has changed from 4+ hours to ramp up to about 3, I usually don’t get a graph between 6am and 11am AEDST, has something to do with different days, it has always been that way except for a couple of weeks in 2011 when she was looking for fresh air

  2. Now we got less quakes at Hierro, but there’s continuous tremor between 2 and 6Hz starting 29.3 at14.00 ish UTC meaning what?

  3. the EQ are still coming another one lot between 3.1 and 4.2 from 4.13 to 5.05, she always takes a bid of a break and gets going again, even the EQ don’t stop…..moving south

  4. Good morning everyone. I totally missed the riddles last night and this morning all solved already. Well done winners.
    All quiet in Iceland this morning but not so for the Poor Islanders on El Hierro. It looks like another disturbed night.
    Thank you dfm for the plots.
    Spica thank you for and all the other Dragons for keeping VC in order. Also Spica you should rest this weekend.I hope you are feeling OK now.
    @ Renato Thought of you today when the news announced Bolt in Rio to begin the start of the run up to the next Olympics.
    I have parceling and posting to do this morning so cannot watch PC or relax until I have been to the Post office and all are safely posted. Then more photography ready for next sales batch to be uploaded. Retired? Yes. But I was less busy when I actually left home to go to work! I must explain I am selling my father in Law’s estate stuff on eBay. He was a collector/horder. So I must first research the items before selling on ebay. At the moment I am attacking boxes and boxes of coins and buttons. If you have ever watched Storage wars on TV Dad’s stuff would fill 3 units and the items are small like watches ,coins & buttons. A lifetime’s hording and so I cannot see an end to sorting in the near future! I am not complaining it certainly keeps me active and it’s really interesting. Every box is a challenge and a surprise. A bit like Iceland’s volcanic activity 😀 😀
    Have a peaceful day everyone. keep warm and safe.

  5. Good morning, all.

    Situation in El Hierro at the moment:

    The local newspaper “Diaro El Hierro” has been summing up the earthquake situation from yesterday and today (til 06:12 this morning):
    – Yesterday, 29. March 2013, there were 16 earthquakes felt by the inhabitants of El Hierro, 14 of these magn. 4 or more, the other two magn. 3,8 resp. 3,6.
    – This morning from midnight, there were again 4 earthquakes with magn. over 4.
    http://www.diarioelhierro.com/t26496/pag02.asp?BD=ESPECIAL%20CRISIS%20S%CDSMICA&id_registro=146634&Id=26496&BDi=INICIO&nt=p&Md=

    From IGN:
    1202296 30/03/2013 00:30:35 27.7071 -18.2866 19 4.3 4 W FRONTERA.IHI
    1202389 30/03/2013 04:12:25 27.7094 -18.2901 20 4.1 4 W FRONTERA.IHI
    1202405 30/03/2013 04:33:34 27.7351 -18.2738 18 4.0 4 W FRONTERA.IHI
    1202434 30/03/2013 05:04:18 27.6924 -18.2807 20 Sentido 4.2 4 W FRONTERA.IHI
    http://www.01.ign.es/ign/layoutIn/volcaListadoCatalogoVer.do

    Additionnally there have been lots of smaller quakes since midnight. Acc. to the a.m. IGN list, around 50 alone over magn. 2.

    • Re. the depth of these quakes, it seems to be increasing (but there we would have to have also the data from the smaller and very small ones). Anyway, on the above list, there was even 1 quake named with a depth of 25 km.

      • One here at 29km deep
        1202476 30/03/2013 09:05:12 27.7655 -18.3318 29 3.0 mbLg ATLÁNTICO-CANARIAS
        Also they seem to be moving further from the island as far more have the locality as ATLÁNTICO-CANARIAS rather than the more usual one we saw at first which was located W FRONTERA.IHI

  6. Looks like the uplift has stopped/paused at most stations, except maybe the HI04 station, which is on the north side of the western end of El Hierro:

  7. This is the update up to march 30th 8h05.

    The earthquakes since 27/03 17h43 are shown as filled circles. Previous earthquakes are shown as empty circles dating back to 26/03 0h00.

    Earthquakes prior to that date and down to march 18th are shown as small black dots.
    The cyan dots represent all the other earthquakes since the beginning of unrest in July 2011.

    Color of the circles is proportional to their position in the list. (see left of colorbar).
    Right scale of colorbar is related to terrain elevation.

    The bathymetry is also shown.

    The events continue to move to the south and most of them are getting deeper. The swarm seems also to orient itself more to the southwest in the last stages.
    However note that around 1’30 there are some shallower earthquakes.

    Also the events happen in majority still in previously virgin territory.

    There were also a few quakes yesterday deep under the El Golfo area (betwen -18 and-18.1 longitude) in what is supposed being the “magma pump”.

    The video is divided in 4 parts. First an event by event timelapse, then a rotational phase followed by a 0-90 ° rotation to show an top view of the swarm. Finally a zoom is made focused on the last event.

    Data from IGN, NOAA, made on Gnu Octave

    • Thanks for the plots – interesting! I confess I don’t understand the quakes going deeper – I’ll wait for an explanation/answer from events or someone who understands more than me. 😀

      • One could have a mental model that the earthquakes are aligned to an preexisting fault plain, or maybe bowl, with a downward inclination towards the center of the island. One could think of magma preferentially breaks through this preexisting fault zone, when departing from the island the trend is up, and the opposite when returning.

        For me the question is rather why the earthquakes do this weird turn at all. Could that be a giant conchoidal fracture of crystalline oceanic crust basalt along which the magma is going down against buoyancy? http://www.sandatlas.org/2013/03/conchoidal-fracture/

      • @dfm. I also really like your plots a lot. Thank you again. 🙂

        @Talla. I am no expert, but I think the quakes going deeper means that the magma didn’t find a layer to get through and is now moving sidewards and down, because it is easier. It will move upwards again at another place, if it can, but perhaps also just stop somewhere and cool down and become part of the stony underground with time as most of the magma seems to become.

        We had such wandering quakes also before Bob was born, not to the north or in the center of the island as expected first, but to the south, because there were weaker layers of the crust where the magma could easier find its way out – see also Chryphia’s explanations about the layers of the ocean crust.

      • This propension to moving to deeper regions was also seen in previous episodes. Maybe it is the other way around and we see activation of another conduit for magma. Or not. I have noted that the shape of the quakes on the sismographs have changed and are now often with a first component before a stronger signal. I attribute that to a progressive action of the magma which opens up a fissure.

        • that seems to be a description of what Carl called ‘wet’ a bit like opening a shaken can of fizzy drink, first a little crack, then a rush of expanding gas and liquid

        • a nice theory that might work here but I admit it won’t work for the 2011 swarm which also moved deeper over time and more or less underneath the edifice.

          • Hi Inge, no I think the active magma reservoir is still Gorbatikov’s hot spot. From here the entire system is getting infused with magma (standard fault propagation). That’s what we are seeing during these swarms plus any purely tectonic quakes from changes in the stress field. The first swarms were generally under the island and each of them is all bunched up into a ball so I imagine these indicate magma moving into cold brittle crust, but here too, the dikes and faults are tiny (centimeters) across which the magma is moving into. This latest swarm also looks like a wave of magma propagating outwards and upwards like a sill until it stops and heads south and down. However, the large quakes at the periphery and heading towards the deep might be purely tectonic in response to the stress. Kind of a moot point whether there is any magma involved in them or not. I still think the main body of magma is sitting directly under the island, right here:

          • PS I’ll correct that… I mean no, I don’t think the main magma body is stting west of the island. But yes, those large quakes could well be ring fractures.

          • And another reason, why I think this is why the main body of magma is located there: this is precisley where this last swarm started before moving west.

  8. 2013-03-30 17:06 UTC
    – A weak seismic period (compared to the last couple of days)
    – Almost impossible to comment on what is going on because IGN filters the listed earthquakes on a too high Magnitude. There is a tendency (to be confirmed by the smaller earthquakes) that the epicenters are moving again towards the East (or the coast) and are showing deeper hypocenters. http://earthquake-report.com/2011/09/25/el-hierro-canary-islands-spain-volcanic-risk-alert-increased-to-yellow/

  9. What is causing then the ring-like structure of the quakes out in the sea to the west of El Hierro if the magma chamber is under El Golfo? Is it a batch of magma mounting to the west of the island?

    I read somewhere, eg. here http://diariodeavisos.es/ that the whole island is pushed slowly to the east by the magma which scientists concluded from the elevation being higher in the western part than in the middle or east parts. Is that correct? And is it due to the magma batch?

      • nah, only a small percentage will ever get erupted and El Hierro has a history of ponding magma intrusions for a while (300 days according to Stroncik) before shooting off a small monogenetic cone somewhere. If there is an eruption, this will probably what happens here again.

        • what I actually think we are looking at is a textbook case at how hot spot oceanic volcanoes grow as much from underplating as they do from sub-aerial eruption.

    • That’s an interesting observation and I think it is due to the fact that there are no GPS stations off the coast. If you take Gorbatikov’s low seismic velocity zone as the center of movement, it’s going to look like the whole island is moving eastwards if all your stations are east of it. Remember this one (found by googling but I think one of us here prepared it): http://quakesos.sosearthquakesvz.netdna-cdn.com/wp-content/uploads/2011/09/eh-03072012-2.jpg
      This is the inferred center of inflation for the 2011 activity that led to Bob. It’s not that far south of Gorbatikov’s hot spot. It also neatly shows all the GPS stations.
      The ring fractures could be a combination of a sill forming out towards them increasing local stress levels and the far-field loading of the crust under the island from the arrival of a new batch of magma like in my first drawing.

      • BTW, this is just a simply hypothesis on my part and I know it is far too simple to be correct. Just putting it out there for discussion.

        • It would tend to psuedo fit with the anomalously large glob of magma that I calculated from the uplift. The number that I looked at and said “yeah… riiiight” and then walked away from.

          Side note about H2S. It stinks. It is also quite startling when a kid finds an easter egg and it turns out to be an egg that was missed from the previous year, that explodes in a puff of yellow powder on him when he grabs it. Actually happened here a few years ago.

      • @Bruce. So in your model the magma does not exit the stack but exerts an upward point force that then leads to rock fracture progressing outwards? I like that as we would not then need to propose huge volumes of magma moving silently and advancing at 5km per day ( – rather fast? -) to get from the stack to the site of the swarm, as dfm’s plots show. It would also explain the various curvatures to the edges of the swarms, along the lines of Chryphia’s giant conchoidal fracture. Nor is it necessary to propose pre-existing sills to direct the swarms – there’s no sign of them from microseismic or gravity data. So perhaps the magma in Gorbatikov’s stack is not migrating but trying to lift the surrounding 30km-radius of crust like a hydraulic ram, and the crust then fractures in the patterns we observe? And that’s why magma has not gone upwards, its trapped in the stack.
        So is the stack acting as a battering ram? – and the swarms reflect both the applied force, diminishing conchoidally with distance, and the susceptibility of the rock to fracture? If the ram has been in action before ( 1793) the rock closer to the stack may have been stress-relieved then, and its now rock further out that takes the load with bigger eqs. A ram effect of consistent oooomph might help explain why the total energy released was similar in each swarm. Oscillation of the force within the column might explain why the eqs come in batches with silent gaps in between of a few hours.

    • Oh, forgot replying. Yes, we know of this, this is where next Katla Eruption will come from (highest). Only we do not know when its magma has been cooked enough. 😉

    • Yes Inge this is a continuous inflation. It has been apparently going on for several to many years. Each summer it inflates more than it deflates each winter.

      also see how the northwards movement of ENTA, this means the source of inflation is right at the center of the caldera, perhaps near the 1755 site of eruption.

      we see a 2-4cm per year northwards and upwards inflation at ENTA.

      when it erupts it will be big.

  10. I find this quiet period in El Hierro odd after the power of the last few days. I wonder if this is the lull before the storm or just the lullaby before sleep.

    • Actually thinking the first one… waiting for a big one?. It seems the expansion to the west and south is finished. Now waiting for the pressure to build.. if nothing tomorrow, check if the GPS measurements show things are (still) going up. If nothing happens there then it might be over, for now…

    • You have to remember that it is a cubic function. so at the beginning you need little matter to get a crack, then you need more…..

        • it’s like inflating a balloon. Plus the fact that there were quite a few “strong” quakes, so it should be a bit like fracking, a lot of fissures were created and it takes time to fill them. If (and I say if) the magma goes on arriving, you will see another swarm soon (it would be interesting to correlate the swarms frequency with time and a 1/x³ law…..)

    • I think there’s a “relese valve” opened somewhere around 29.3 at14.00. (I asked about the continuous tremor @2-6Hz earlier,) so we may see less quakes, and maybe even deflation, Could be waay wrong though…

      • Dunno about actual events coupled with changes in the traces… but MRK has noticed a handful of warm upwellings out to sea. Nothing definitive, they come, then they go.

        • That would then be conducive to cone-building to the west of El Hierro?

          Just curious – can MRK monitor warm upwellings along the mid-Atlantic ridge?

  11. Did we discuss this tremor plot from some days ago? This is Gran Canaria on March 22. Is there onset of harmonic tremor in the signal? (where the vertical line is, around 11:30) http://www.01.ign.es/ign/head/volcaSenalesDiasAnterioresCuasiReal.do?nombreFichero=EOSO_2013-03-22&ver=s&estacion=EOSO&Anio=2013&Mes=03&Dia=22&tipo=2
    At EGOM the same day, around 4-6:00: http://www.01.ign.es/ign/head/volcaSenalesDiasAnterioresCuasiReal.do?nombreFichero=EGOM_2013-03-22&estacion=EGOM&tipo=2&Anio=2013&Mes=03&Dia=22
    It’s actually still there on all of the other stations (so no human activity), except the El Hierro stations, perhaps there missing due to the different scaling.

  12. 2013-03-30 18:23:28 -20.078 64.509 1.4 4.9 auto
    2013-03-30 17:10:04 -20.094 64.481 1.0 2.8 auto
    2013-03-30 14:55:19 -20.025 64.503 2.4 4.0 qu
    2013-03-30 14:48:59 -20.03 64.5 1.6 4.7 qu
    2013-03-30 06:34:39 -20.066 64.485 1.1 5.2 qu
    2013-03-30 06:30:47 -20.032 64.497 1.2 6.1 qu
    2013-03-30 06:25:34 -20.072 64.478 0.9 4.6 qu
    2013-03-30 02:49:30 -20.046 64.499 1.2 3.4 qu
    2013-03-30 01:52:01 -20.044 64.499 1.1 3.8 qu
    2013-03-29 22:12:34 -20.067 64.483 2.1 5.1 qu
    2013-03-29 21:06:46 -20.048 64.488 1.4 6.3 qu
    2013-03-29 19:45:16 -20.031 64.504 1.2 4.7 qu
    2013-03-29 18:58:13 -20.032 64.502 2.6 5.7 qu
    2013-03-29 18:51:39 -20.021 64.496 1.7 6.1 qu
    2013-03-29 18:20:06 -20.046 64.504 1.9 4.3 qu
    2013-03-29 18:15:10 -20.048 64.488 1.3 4.6 qu
    2013-03-29 18:07:23 -20.035 64.5 1.7 4.0 qu
    2013-03-29 17:49:22 -20.053 64.488 1.2 6.1 qu
    2013-03-29 17:48:42 -20.038 64.501 2.2 3.9 qu
    2013-03-29 17:41:11 -20.071 64.486 1.1 7.0 qu
    2013-03-29 17:39:45 -20.054 64.496 2.3 4.7 qu
    2013-03-29 17:28:29 -20.048 64.503 1.3 6.2 qu
    2013-03-29 17:27:17 -20.045 64.489 0.7 6.4 qu
    2013-03-29 17:25:31 -20.047 64.497 2.0 7.9 qu
    2013-03-29 17:24:20 -20.055 64.498 3.5 4.1 qu
    2013-03-29 14:28:59 -20.052 64.501 2.1 3.7 qu
    2013-03-29 14:05:05 -20.058 64.482 1.1 7.8 qu
    2013-03-29 14:04:00 -20.068 64.489 1.9 6.1 qu
    2013-03-29 14:03:43 -20.066 64.506 2.8 3.5 qu
    Summary of Icelands, Langjökull swarm of yesterday and today. IMO lists total of 30 quakes now (magnitude and depth in two of three last columns and “checked” (qu) in the last one). Do these have possible “Volcanic orientation” (north east / south west). That is contrary to what I had previously thought but can be wrong of course. *not expert*
    Below is (copyright of the photographer) photo of the exact area and my estimated orienation of this swarm, with them two lines at far left showing the orienation of the Jarlhettur volcanic cones / fissures, these are visible on the photo too at extreme left. As everybody can see this is the idel location for a small trourist volcano, not far from Gullfoss and Geysir “golden triangle”. 🙂 Happy Easter !

  13. Dragging this down here so I can respond.

    Peter Cobbold says:
    March 30, 2013 at 20:01 (Edit)

    @GL
    I think I get you – a heat gradient from 1793 magma might contribute to the rock closer to the stack being more ‘ductile’ – less prone to fracture – than colder rock at greater radius?
    From your plot the bigger eqs ( mag 4s) in the present swarm at 15-20km radius might be expected, and not expected closer in, as observed?
    Would that conical shape to the lower bound of the 2011 swarm also fit with this plot? as you plotted earlier:
    https://volcanocafe.files.wordpress.com/2012/09/peter-fig3.png?w=640&h=649

    It might. The material would be more forgiving of lesser stress levels and might act as a natural filter so that only the larger stress levels would be able to make a quake.

    Unfortunately, none of us are down there to poke at it with a stick to see what it is doing.

    I still think of that as the material coming out of it’s repository. That column could be the actual “chamber” where the mantle material intruded, and like when trying to over fill a bottle, the sides cracked and it leaked out.

    • “Unfortunately, none of us are down there to poke at it with a stick to see what it is doing.”
      Oh what a lovely picture that conjures up!! 😀

      • Stick Poking. One of mankinds first usages of a tool. It probably became quite popular. Second only to falling off of stuff as a method of demise. Poking a cat with a stick is never a good idea. See, they are smart enough to know that what is on the other end of the stick is controlling the poking.

        • Years ago, i had a Black and Tan Coonhound. Bit of a runt, but a good trail
          dog and could hold her own with and larger dog on the run. Ok. my Pop who
          spent many summers of his youth with his Mountain (Ok Hillbilly) relatives in
          the Ozarks of Missouri and Arkansas, and as such he was a midding fair Houndsman.
          We usually had a a Dog or two around,Bluetick, usually but every now and then
          a Black and Tan.. Like my Pup. She was always trailing something.Well one day,
          We heard thise commotion up our little creek that flowed into our stock pond.
          Pop grabbed the .22 pistol and I the .30-30 out of the Land Rover (yes, you read it-
          Land Rover.-Pop loved that thing.) . We go up to the area where ‘Ol Pupps was
          Bawling her head off trying to get at whatever was in the tree.she was making an effort to climb the tree, but to no avail. Thank God. We look up and here is our snooty
          neighbor’s Yellow Persian Cat. Not happy. Not about to come down either.
          So Pop gets this idea from the Good Idea Fairy that just Whacked him over the
          head:”Lets get a stick and push him out and Dorothy (Our neighbor who thought
          Us McCoys were well, Hillbillies.) wouldn’t be the wiser.” So Pop grabs a big
          willow limb, I hold Pupps while Pop. pushes Kitty Kat (20 lbs of Fancy Feast
          Sculpture.) out. Kitty Kat comes down. and lands on Pop’s head on top.
          Kitty Kat is also vewy,vewy, angry. and is raking Pop’s head and ears rather
          well.Pop has his work gloves on and is trying to pull this fat, angry, cat off.
          Pupps is wanting to help too. finally, Kitty Kat with a few swipes at moi,
          too makes it over the fence and down the road. I now have a lead on Pupps,
          and she is dying to follow Pop and I look well, shredded,.As we got to doc
          Stoddard’s office doc asks;”Now what…”
          Never poke a cat with a stick….

        • I’m thinking that mankind’s tendency to poke stuff with a stick eventually led to the idea of a spear. “Hmm.. if I put something sharp and pointy on the end, it’s less likely that it will try to claw my eyes out…”

    • Still nº 8 in the top ten of days with most earthquakes since the crisis started in 2011, as I read on FB-Avcan…

    • yet only normal curve – Rize be dramatic if related to Hekla – But one incoming – the 0,6 R at Galtalækur is “on verge” be Hekla, but is not inside Hekla volcanic zone (can be side effect) time will tell, still waiting for quake eight. Slamming the door on the Hekla parking lot does not count! 🙂

      • Yes it is a bit outside of Hekla, just a couple of kms from the base of the mountain. Well, if Hekla chamber is around 10km, this quake can be at its edge, because it is 8.4km and of its position. Inside the chamber we don’t expect quakes because there is less solid rock and less resistance. But any magma movement can make pressure in the rocks and create earthquakes as it tries to move upwards.

  14. OT – How VC ruined watching Joe vs the Volcano for me

    I just finished watching that movie. For the most part, it’s a cheesy story, but there is a volcano at the end, so I was game to watch it. For those who don’t know the movie, Tom Hanks (Joe) is hired to jump in a volcano. So in the last 5 minutes of the movie (spoiler alert), Joe and his girl friend Meg Ryan stand on a plank over the mouth of the volcano, and then just jump in the crater. At the same moment, some steam explosion comes out of the lava lake and catapults the 2 jumpers many kilometers away at sea, where they land unscathed. HA ! Likely story… No way in heck !!! They should have been properly overcooked, at the temperature of this material.

    Then the whole island, a perfect stratovolcano shape, sinks vertically in the sea as the volcano erupts (oh ya, and where is the ash column ?). At the end the sea enters the crater and the whole island is gone. No Krakatoa-like boom when the seawater reaches the magma chamber, no vaporized steam, nothing… The whole thing was quite anti-climactic when you expect something more volcano-like. I did not expect a lot of real-life volcano facts, but I realized that reading VC for a few years gave me enough knowkedge to look at the ending in disbelief ! To quote EK : Premise 1 (Yeah, not really). Science 1 (the volcano is there, otherwise if I could give it negative points, I would). I had a nice time watching the movie, but the ending… naaahhhh !!!

  15. On that note, I’ve always thought the Krakatoa eruption would make a really good background for a movie. You could take it a lot of directions… go straight up disaster, or make it more of a drama involving the east india trading company, relations with the foreigners in indonesia, all with the background of one of the most famous eruptions ever seen.

    My only problem with this is that they would probably butcher how the eruption actually happened. somehow.

    There is something at least slightly romantic about victorian era merchants / aristocrats in an exotic land with an exotic natural disaster at hand however.

  16. There is a small up tick in EQ at El Hierro but actually, it is quite calm. The GPS charts are also suggesting that we have an Eastern break. Family time..

  17. Happy Easter everyone 🙂 I hope the Easter Bunny brought you some chocolate eggs 😀 He missed my House 😦 I think Meg frightened it off. 😀
    I have been trying to find tremor graphs for Hekla days before the 2000 eruption. No Joy! I only found The actual eruption 27th Feb and there is little to see and hour or so before. I really wanted to see the graphs some weeks or days before to compare with what we are seeing ( or not seeing ) now. of course the equipment is now probably more sensitive and accurate but it would be interesting to study it to see if anywhere else nearby was showing tremor too.
    I do think the quakes circling the base of Hekla are important. There have been some really odd ones over the last few months. I do think Irpsit is right in his last comment. But then I am a blonde ageing amateur. 😀
    The strain is still an upward trend http://hraun.vedur.is/ja/strain/1sec/index.html

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