Pevolca reacted on the earthquake series that happened yesterday and set the western part of the island to a “yellow alert zone”. All this happened in agreement with the government of El Hierro.
Full report (in spanish) and a short excerpt for your information: Closing the lane of the tunnel closest to the exit in Frontera, closing the length of road HI-50 between ‘Cruce de La Tabla’ and ‘Sabinosa’ and the access road to ‘Playa La Madera’, of ‘Pozo de la Salud’ until the crossing with road HI-503.
Yellow informative alert for the population at the zones limited by HI-500 at ‘Pozo de la Salud’ to the South, en the crossing between HI-500 with HI-400 at the crossing known as ‘El Tomillar’.
The best sites to get the newest information are:
Those 2 sites are not normal blogs like VolcanoCafe publishing a full post every few days but they report close to the “action”.
dfm created a brilliant plot and explained it:
This is the update till 18h43 today
Today there were a number of strong (for El Hierro) earthquakes with quite a few over mag 4 which is quite rare.
In the list of earthquakes you will notice that for the strongest earthquakes there is only one event of similar magnitude (4.6) and that in all the events with mag >=4 (16 out of more than 17000 !) 5 came to happen today.
(The ful list of quakes dfm used can be found in his comment on “Watching Hekla“: dfm says: March 27, 2013 at 21:15 )
Without wanting to be fear mongering, I find this situation unprecedented. If you add this to an also unprecedented trend in the upward component of the GPS, this situation begins to pose a number of questions. Happily (if one may say) the bulk of the seismicity is located at sea and not on the island emerged part.
Meanwhile here is the earthquake update for the period since March 26th 8h18 and 27th @ 18h43. It includes the 4.6 quake.
The color of the quakes is linked to their position on the list (more than 1200 events since March 18th).
I will probably change this next time as the color scale loses its interest.
It is interesting to note in the time-lapse animation that there are first some cluster of quakes in the previous parts, leading to a hypothesis of a “sill” of sorts or at least to an accumulation of rock breaking in the same place. Then most of the “strong” (meaning over Mag 3 ) quakes seem to appear on the border of that cluster (look at 0’20”). Could it be that there was some renewal of magma arrival (a new “bolus”) and that the constraints bring some rock breaking on the limit of the previous cluster. I will only repeat that these new events happen in a zone previously devoid of earthquakes.
The 4.6 event can be well see at 00’49” on the center-left part of the plot, over the 27,6 mark on the abscesses.
Do look at the end of the video in the zoom sequence (1’22” and 1’28”)
On the right side of the colorbar the terrain elevation scale is shown. Magnitude of the events (sorry I stopped at 4 !) is shown on the lower part of the plot.
Data from IGN and NOAA, made on Gnu Octave.
Peter Cobbold noted: Bearing in mind the GPS stations are ~15km away from the swarm centre the 100mm uplift in ten days is unusually high for Hierro. Previous swarms have been co-located with the GPS stations and resulted in smaller uplifts over longer periods,IIRC.
Yesterdays trend. El Nathan did not really see a tendency of the earthquakes coming closer to the island.
In case more earthquake swarms happen, there is the possibility of rockfall (or maybe even landslides). At the very moment an eruption on the island is unlikely in my eyes. (Personal layman opinion.)
Links to watch El Hierro (besides the cams) are to be found on Wonder what Bob is up to.
Lets not forget some here like Jamie and Islander are still on a 24hr Hekla watch.
Hekla is still on alert level yellow but not all too much happened close to it yesterday.
Islander also informed us:
Hekla “news service” latest scoop : IMO has brought back online the fourth (4) SIL for monitoring the greater Hekla area. These are HAU from the west, fedgar. (http://hraun.vedur.is/ja/oroi/fed.gif) from the north, VAT from the east and MJO from the south. Nothing EQ wise then can escape the sharp eyes of the IMO staff. http://hraun.vedur.is/ja/oroi/index.html
Fedgar is not on this overall map.
Again the Hekla links:
- Hekluvöktun Hekla Data
- Hekla GPS
- Borehole Strain and Hekla seismicity
- Website on Hekla ( Swedish)
- Seismic stations close to Hekla
Other sites have the information about the earthquakes too but dfm’s plot is only on VC.
507 thoughts on “El Hierro’s western part on “Code Yellow”.”
Some talking about the power being off…
and on again
they have lights now, webcamera on Frontera side
(and its night of course, not plesant having potential eruption possibly)
Oh Dear! The poor islanders are having a bad time again. Bobbette is really going some at the moment. My best wishes to all and stay safe.
Bardabunga is having a little quake session too but nothing like El Hierro.
Great minds think alike! 🙂
Was also looking at that table. Interesting depths: 0,1 – 3,8 – 7,5 – 19 km.
Tremor rather lively too at Bárdarbunga: http://hraun.vedur.is/ja/oroi/dyn.gif
And there was a quake near station JOK. http://hraun.vedur.is/ja/alert/2013/mar/28/065-PGV.jpg
And not only with are having a closer look at the Vatnajökull region it seems: http://hraun.vedur.is/ja/alert/2013/mar/28/067.html
Getting a bit tired it seems – tried to write the Icelandic “við” (= engl. “we”) acc. to English pronounciation …. (which would be “with”).
no problem, all forgiven ;- all write badly when the importance of beeing quick overtakes quality of thought *attempt at wise words*
Its seems that set of Quakes knocked out the lights in places on the Island, must be scary in the dark, it just seems to get worse for the locals.
no, they have lights on Frontera side, webcamera is working too 😉
Strain meters are getting noisy again. But she needs to wait until Sunday afternoon. That would be best for me. 🙂
Does anyone have the strain measurements from the week before Hekla erupted in 2000? I lost my copy.
*note, they are not using same units (then it was nano strain/min) but I expect charts go up / down similar, estimated BUR drop 300,000 units on uncorrcted plot, the other I have no idea how it will end up.
Good evening everyone … I have had a migraine all day … deep joy NOT … Bob’s playing up again I see …
jepp, almost as all of Bobs family be there and having a party
– seems all the action be there tonight
Hope you feel better soon.
A wonderful friend arrived this morning with hugs and the pills that I had run out of and I am fine now thanks karen!
Which isn’t a joy neither to the poor islanders…
Should have been an answer to Kilgarrah.
I really worry about them …. they must be having a ghastly time.
I agree, I would be wetting myself every time those quakes start. Sorry for the graphic image. 😉
Is it Dragon sympathy for Spica’s concussion? Hope you both are feeling better soon.
I have a question …. is there any fear that these quakes could be affecting the stability of the other Canary Islands?
in my opinion – none whatsever
1201807 28/03/2013 22:35:43 27.7709 -18.2818 20 3.4 mbLg W FRONTERA
1201804 28/03/2013 22:33:00 27.7225 -18.2894 18 3.7 mbLg W FRONTERA
1201802 28/03/2013 22:28:39 27.7183 -18.2899 19 3.8 mbLg W FRONTERA
1201800 28/03/2013 22:25:31 27.7303 -18.2611 21 3.6 mbLg W FRONTERA
1201790 28/03/2013 22:22:47 27.7378 -18.2540 22 Sentido 4.1 mbLg W FRONTERA
1201801 28/03/2013 22:14:05 27.7608 -18.3166 10 3.2 mbLg ATLÁNTICO-CANARIAS
1201799 28/03/2013 22:13:42 27.7699 -18.2656 3.3 mbLg W FRONTERA
1201797 28/03/2013 22:08:00 27.7114 -18.2621 18 3.7 mbLg W FRONTERA
1201803 28/03/2013 22:07:33 27.7281 -18.2961 12 3.0 mbLg W FRONTERA
1201786 28/03/2013 22:01:05 27.7191 -18.2751 20 3.5 mbLg W FRONTERA
1201789 28/03/2013 22:00:23 27.7313 -18.2888 18 3.4 mbLg W FRONTERA
summary : ten 3+ and one 4+ alreadi in this episode
Right, I need some sleep …. if things continue in this vein shall I skip the friday NtV riddle? Not sure that it would be appropriate, on the other hand it could keep us occupied as we watch and wait ….
See what it looks like tomorrow.
Maybe it would give you a badly needed rest Kilgharrah. Migraines are not to be trifled with!
Still trying to get a pattern in time, no real frequency found. Maybe looking for pi…
Well I must get some sleep now. I wont say beauty sleep as I am well past hoping for miracles. 😉
Hope El Hierrans get plenty of sleep tonight too.
El Hierro: Estimated energy to 22:50 this evening: http://oi48.tinypic.com/2uxxo8z.jpg
Hi karenz… just got home… Schierously… Fcuk me…
GL Edit: I didn’t know you were in to [x]-RX 😀
It’s eye-watering 😕
I think I deserve a shot of whiskey. 60 miles to go then I can sit and ponder.
Pondering is the best time of the day.
Watch the moon behind Hekla while you ponder.
I missed the moon. But I was able to watch the Sun on the way in. It’s behind the bug carcasses on my windshield. BTW, it was clean this morning.
That dark fuzzy thing that the Sun is peeking through? Smoke. There is a controlled burn in the North part of the county. I’m all for controlled burns. It clears out the undergrowth and prevents any fires that do occur from becoming crown fires. It’s also the sort of thing that pines thrive on.
My issue with it is that it seems that every time we have a good rain that scrubs the air clean, someone will do a burn and trash the air. I would love at least one day of driving without that pervasive cypress smell hanging in the air and screwing up everyones sinuses.
Lurk, you and me both.Here we do the same thing. Nice day. and then the controlled burns. One thing that usually happens is a late one isn’t put out properly or they miscalculate the Haines Index changes and the fire goes over the hill.
Here is the Haines Index explanation:
Level 6 is very ugly.
You don’t want to see 6 in Late July or Early August.
The part about that photo that really stinks, is that 2 C-130s went by low just after I shot it. They were on a training sortie out of Eglin.
In Iceland there are also 2 weeks in April for the farmers to burn their meadows.
the bottle-Seismometer is back online XD
history always repeats itself – GL will be happy 😉
GeoLurking will be so happy. 😉
Would be if it wern’t behind the snoopy facebook log in.
Might work on the PC, of I can extract it with the wifes account. She’s into the exposing of personal data to the ravages of the internet.
Woot! Works fine on the PC! Evidently Facebook wasn’t going to let me see is unless I agreed that they could infect my phone. (Ain’t happening)
Did something significant just happen? Visitor number almost doubled in the past hour…
Maybe the last dfm plot got popular through the “netvine”…
A glance in the crystal ball reveals that Steve Quayle is watching us….
can we have traffic figures ???
Not really formated for it, but here ya go.
Search Engines 14
ah, and I thought there were NEWS ! doh
They seem to have eased off, and were mostly 1-view-per-visitor without commenting, so I’m guessing maybe another peak when the USA wakes up and the watching is over 🙂
Btw chryphia, working the (involuntary) nightshift last night? 😀
Blame it on the moon…;-)
Yeah, the moon looked orange here yesterday, that means it’s a so called “Dutch moon”, which refers to the old Celtic wisdom which states that some people who believe doom is about to happen will be having a large influence on daily life that night. And indeed, the prophecy turned out to be true again 🙂
And for the record, the link on there was to the main page, not to any article, so it takes an extra click to get to a place where the visitors can comment. But because of this we are only 5000 views away from being the busiest day ever at VolcanoCafe, and it’s not even mid-day according to the WordPress clock 🙂
Been trawling through AVCAN’s FB page, translating with our friend Mr Bing. It appears that someone in La Restinga has not felt the EQs in the last day or so.
Is this because the current swarm is not occurring on the NNW SSE rift?
That or they are anesthetized. I probably would be.
New episode of strong spasmodic tremor since 2:35 UTC and two shallow earthquakes in west El Golfo bay.
2013/03/29 01:37:34.59 27.7710 -18.1306 4.40 km 1.50 mblg W FRONTERA.IHI
2013/03/29 01:39:10.80 27.7664 -18.1236 2.40 km 0.80 mblg W FRONTERA.IHI
Pretty good sized quake at about 2:52 UTC. Probably a 4.6
Big one around 3:15 UTC too. These are big quakes and I wonder if such a series of 4+ mbLg has ever been recorded in the Canaries?
Downgraded to a 4.3.
As a series? Probably not recorded.
Back 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… that would be pretty awesome to see. (and worrisome if you are on top of it).
My only real concern about the volcano aspect of it, is that I have a feeling that if it’s going to go subaerial, it is not gonna fiddle around about it. That also applies to any new suboceanic eruptions. Back before Bob, someone noted that the tremor kicked in and by the time we noticed, Bob was already doing it’s thing.
Note about the above. “conceivable” doesn’t mean certainty. The fracture could quite easily be horizontal, which given the layered structure of a volcano is probably the most likely. In that case a series of sills would be formed.
Based on the quake patterns that we have seen over the last year or so, that seems to be the main thing that it does.
The whiskey hit the spot. It doesn’t go well with tacos, so the chaser took care of the indermediate flavor issues.
Yet anothe note about the above. Sills are horizontal intrusions, Dikes are vertical. If a dike makes it to the surface, you get an eruption.
(mainly for the transients who stumble in)
Different sorts of intrusions (from Wikimedia): http://commons.wikimedia.org/wiki/File:Intrusion_types.svg
Well frankly I do not know. The events are getting deeper and going south. AS written before I’ll put back all the old event location to see if it goes back to previously trodden paths. For the time being this is not so, but we’re getting nearer.
I’m not too sure about an eruption on land, as the bulk of the action is quite far from the coast and quite deep also.
Jamie found a cool link about the Activity at Hekla.
Jamie done good. Thats a sweet link. Thanks!
I found it on the weekly report page, on the icelandic side. They sometimes throw in some little tidbits. If you look at the top of the map you see a number of links. The first is “Skjaftlisti”. quake list. next is “week before” then comes “next week” And then my favorite “other weeks” you can see back to 1994.
Thank you, very good to have this information. 🙂
Thanks for this Jamie! 🙂
5.14 to 5.22, I am not sure how many large quakes
there is one 5.16 about 5-6km deep on the way to bob, but not listed on the earthquake list, my line is dropping out again, I did write this post before and halfway it went bling/…
Rockin’ and Rollin’ again:
1201949 29/03/2013 05:20:12 27.7087 -18.2715 19 3.6 mbLg W FRONTERA.IHI
1201948 29/03/2013 05:15:08 27.7370 -18.2708 20 4.1 mbLg W FRONTERA.IHI
I doubt the Herreños toward the western end of the island got much sleep last night.
Difficult time for them. (:
I can’t even begin to imagine. I live in the ultra-stable south east corner of Queensland, and have never felt so much as a tremor.
Really picking up at El Heirro.
I know these are only tiny but they are directly under the island and very shallow. I hope they aren’t the start of something.
1201829 29/03/2013 01:37:35 27.7204 -18.0837 2 1.8 mbLg W FRONTERA.IHI – El Hierro
1201830 29/03/2013 01:39:11 27.7168 -18.0851 2.2 0.8 mbLg W FRONTERA.IHI – El Hierro
Interesting Alison. I checked out the location on Google Earth and both those quakes are very close to the ridge across the island and more worrying, they are close to an area of old cones.
As Spica quoted though, this could be the case:-
“They suggest the shallower quakes are surface quakes as the landmass adjusts to the elevation it experienced.”
Picking up again from just before 8am
Check out the unusual spectra from the quake at 7:14 an odd shift to the lower frequencies
Is there anyone on at the moment who is knowledgable that can comment on this odd quake?
big tornillo? No S wave (direct attack), and a long coda….
I thought that but don’t feel experienced enough to comment.. There isn’t a depth for it that I can see. Do you think it is significant magma movement?
Well I’m no specialist. I still have to read all the Mc Nutt article……plus this event shows nowhere on the EQ list ( one 2.5 @ 7h09 then another suale @7h31…) difficult to say something on that really. The thing I notice is that there are quite a few quakes for which the sismometer is saturated.
The 4.4 quake from 8:42 is also very heavy in the lowest frequencies. I always associated the lower frequencies with moving magma, but I can be wrong
8.15 two very strong eq, looks like ht is getting organised
’twas a 4.0 at 16.8 km
Further south and nearer the coast too.
1201996 29/03/2013 08:13:52 27.7013 -18.2324 16.8 4 mbLg W FRONTERA.IHI – El Hierro
Good morning …
of FB, a Alicia Fernandes:
Uuuyyyy what happens! A 09:42 felt three shocks that moved the sofa where I seats, something that did not go so far by this intensity! I can imagine how it is iron, which is always restless. Many of encouragement for everyone! (Translated by Bing)
Important to know that alicia’s sofa is situated in puerto naos on La Palma !
4.4 seems a bit low to me.
I had assembled to match the link of Michael Ross a live report afterwards when we talk about numbers, it is sterile, of course, just as the opposite
Both sites i linked in the post have good updates on what was happening last night and early this morning. They suggest the shallwer quakes are surface quakes as the landmass adjusts to the elevation it experienced.
Dont know for sure if this video was already linked:
It is from the 27.3.
9.42, very strong one… >4.5? or more close again..
according to the alert message it is a 4.4 at 18 km.
What alert message?
http://earthquake-report.com/, registered for all 3+ EQs for Spain (canaries). At that time there were only very few (maybe I should change for 4+).
1202010 29/03/2013 09:41:48 27.6919 -18.2489 18 Sentido 4.4 mbLg W FRONTERA.IHI [+]
To all who bring translated things here to VC.
First thank you for searching things and bringing them, but could you please exchange iron with El Hierro when you copy paste.
Please. hierro = iron in spanish. But a text gets hard to read when Bing translates crap. 😉
Last time we had many more such translation mistakes, I ´ll give a kind of dictionary as they come up again. e.g. Frontera = border ( i dont speak spanish very well but well enough to read most reports and pages in the original language spanish.)
Please excuse Spica, will not happen again 🙂
Reblogged this on Zenobiusz's Blog.
//edited due to redundance chryphia
The translation crisis? Reblogged 🙂
Should have been answer to Harrie 10:39.
mine should be linked to zenobiusz at 10.28… but the link is now gone…
This looks weird. Problems with the graph?
Eeek is the seismograph packing up?
Ooops didn’t notice Bobbi was already on the case 🙂
This one is still working though
Here is another 3D plot, no overlays this time ;-).
It shows the current swarm and the older earthquakes in two seperate color scales. I wanted to see where the 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
I confirm some reactivation, I redid the plot yesterday to see the situation with the older quakes and there are a few quakes in the feeder zone….but not that much.
I wonder if those deep Golfo eqs are a response to the GPS motion? In 2 weeks Fron has moved up only slightly, but the west (Sabinosa, Orchilla) has now risen 120mm. The swarm centre is further west by as much again, so if we had seabed GPS there the lift might be 240mm. I imagine the surface 10km-thick to be lifting as a rigid body, putting Fron near the point of flexure. So the Golfo deep eqs – well below the 10km-thick rigid slab – might be in a zone of decompression. Hence the eqs.
Godabunga took over some action from Hekla, it seems: http://hraun.vedur.is/ja/Katla/god_trem.gif
But I also still have an eye on Bárdarbunga. GPS shows a bit of subsidence: http://strokkur.raunvis.hi.is/gps/DYNC_08.png and there is still lively action on the tremor plot: http://hraun.vedur.is/ja/oroi/dyn.gif (no expert)
quake in unusual location. an eruption in that area could set off a good flood if a fissure opens up under the glacier, besides it is near some very large (old) calderas, but its unusual get quakes on that side
Yes, but I wouldn’t talk about eruptions there as long as there aren’t quake swarms or tremor and/or pronounced uplift somewhere around Langjökull. This arm of the MAR is a rather inactive one, see eg. http://www.soest.hawaii.edu/GG/FACULTY/SINTON/publications/wvz_g3.pdf
There are not a lot of movements at the nearest GPS station and the discernables are in downward direction: http://strokkur.raunvis.hi.is/gps/LFEL_08.png
And yet another 4 magnitude quake at El Hierro.
1202056 29/03/2013 12:15:55 27.7195 -18.2742 20 4.0 mbLg W FRONTERA.IHI
Another ‘big’ quake at 12:43. Looks like being a busy day for seismicity on El hierro again. How much longer can this last before something comes up somewhere. The depth still seems to be pretty deep.
This looks on the seismograph as a relative small event.. So I guess the “big” will be again >4. 1202070 29/03/2013 12:30:41 27.6643 -18.2320 14 3.7 mbLg SW FRONTERA.IHI
M4 quake now http://www.emsc-csem.org/Earthquake/earthquake.php?id=310376
Roger P. Frey@efadi_LP9 min
Still heaps of activity on #ElHierro , the pressure of Magma releases in some earthquake but it is quickly reloaded. http://www.ign.es/ign/resources/volcanologia/DATOS/2013/CHIE/imagenes_sismica/HORA_SP/CHIE_2013-03-29_12-13_sp.jpg …
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.
Earthquake report says there were 51 Mag 3+ and 8 Mag 4+ till 11am
CJUL link still works best probably because it is not linked directly from the ING site and therefore less frequented, so it is more like a VC secret. ( pssst 😉 )
with time we become the world leaders in volcano watching
*another attempt at world domination*
Btw here is very devoted site with webcams, and most we now watch regularily are on one page. http://www.malinpebbles.com/Images/FOTOS/Meine-Webcam-Seiten/pubweb/WELT.htm
At the bottom you find more pages with more than one cam..
Thanks to Petra who is preparing this. A german native speaker whom i do not know nor have ever seen here.
At the moment, Nevado del Ruiz is not disguised in clouds which seems to be rather seldom.
They were mostly unsuccessful in the end: http://commons.wikimedia.org/wiki/File:Napoleon_Bonaparte.jpg 😉
Answer to Islander á la Hekla 13:26
ok, skip Russia
Good morning. Some more newds from PEVOLCA:
“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“
Although I see the trend moving rather to the SE, not SW, which has already been pointed by some of AVCAN commenters.
Also there are reports of 17 cm of inflation over FB!
On the IGN plots I don’t see more than 120 mm – which is also a lot (HI05): http://www.01.ign.es/ign/resources/volcanologia/jpg/hierro1SVVRTRF_neu.png
Think it depends on where you take the start point for the inflation.
We’ve been here before with earlier swarms, but it “feels” to us like the entire edifice is infused with fresh magma like freshly harvested honey comb dripping with honey. The reality, though, is probably quite different and the problem is one of our perception. To me it looks like there is a huge wad of fresh magma. But I imagine the bulk of it is still in the main feeder (Gorbatikov’s low velocity zone) and underneath the crust. Nevertheless this volume is lifting the island (hence the inflation) and pressurizing the system (leading to the swarm out to the west) The seismic activity just represents the outer boundary of the system. We shouldn’t forget that most of the magma is probably still very deep in the middle of the island and is under great pressure. Why it’s not finding a way to rise up to shallower levels I have no idea. But this is the same question we’ve posed with every other swarm to date. Also this is very likely standard behavior at these ocean islands with most of the new magma infusing the lower crust / underplating the edifice and not erupting.
I am no expert but most of the EQs have appeared to be tectonic / volcanic tectonic so the ocean crust tearing, probably as a result of magma pressure closer to the “main feeder”.
I wonder if there is a clue in the curved, ‘keel’ shape to the lower bound of earlier deep swarms, and which is starting to appear in this swarm in N-S section. If Gorbatikov’s stack has consistently been the magma source and the point of its exit close to the upper bound of each swarms, then we’d have a ‘point source’ whose influence would diminish roughly spherically, to give those curvatures. It would also give the conical appearance to the base of the first swarm, although in E-W section the lower bound is not obviously curved when all swarms are summed.
But as you say, what stops the magma erupting out of the top of the stack? To me the top 10km appears to be lifting as a solid slab with very few eqs within it. Perhaps the if the sedimentary layers accommodates the bending strain and compression silently.
We could conceive of a cold dense pluton several km across blocking the tip of the stack, but that is not apparent either in Gorbatikov’s microseismic data or in the gravitational density plots. Puzzling indeed.
re. Curvature: note that the curvature is misrepresented ( de-emphasised) in these plots:
The depth scale on the sectional plots is contracted by a ratio of about 5/3 compared with the map. So curvature is more pronounced than depicted.
Peter, you mean kind of like this?
(yeah Bruce learns how to draw ;-))
Thick black line denotes cold impervious volcanic deposits (why they would be impervious I have no idea)
Thin black line denotes rough outline of swarms (view from the south)
Thick red line denotes heavily simplified base of oceanic crust
Yes Bruce, and that was quick! Your diagram rather suggests that pale blue ‘hook’-shaped structure overtopping the stack might have something to do with stopping magma coming upwards?
quick? Grief. I’m totally new at this game.
btw, yes I think you are right, that hook shape is probably composed solely of older erupted material sitting on a thin compressed layer of sediment. The blue swarm seemed to make it past the sediment and into the edifice (8km deep is pretty shallow when you think of the weight of the island on top of it). I haven’t got a clue about geochemistry but is it possible that the ocean sediment sandwiched between the ocean crust and the overlying volcanic edifice has metamorphised into much hard material due to the combination of heat and top pressure? Could this be acting as a cap? Is so, you’d expect an eruption to squirt out the side from this current swarm.
typo: hard -> harder
The link – for newcomers – to visualisations of the structures below Hierro:
doh.. penny dropped.. sometimes it’s actually good to draw these things for yourself. I know everybody else probably knew this all along, but I only just realized that big blue swarm (second half of 2011) is slap bang in the middle of the cold feature shown by Gorbatikov situated between the E and W feeder columns.. and all the swarms are located in “cold” (read brittle) areas surrounding the central feeder stack. Shows up quite nicely.
Another drawing now Bruce 😉 Please.
Ah, you’re a hard taskmaster Spica!!
How’s your head today?
ok, here you go. I’ve corrected the vertical scale to match the IGN chart to Gorbatikov as pointed out by Peter above. The Blue line denotes the blue swarm in late 2011.
Note how it snuggles nicely into that cold area.
What would be powerful would be to superimpose the microseismic sections , or the gravity sections, upon horizontal slices comprising only those eqs that occurred at the same depth. But that means going back to the eq date to sort by depth – beyond me. GL did it for a vertical slice of 2011 swarm, see figure3 in my now discredited effort:
Note that blue ‘hook’ and the top of the swarm…
.. and while I’m at it, here’s the “dead zone” or Gorbatikov’s low velocity zone (hot spot) seen in the seismic record:
Peter, I think you posted the wrong link. Fig. 3 is here:
Interesting that Lurk has got his (blue) swarm slightly more westwards than mine. His is probably more accurate as I just lined up the edges of the island in Gorbatikov’s chart with the edges of the island in the IGN chart.
But like a Catherine wheel with swarms as the sprays of fire, and a blank centre.
Thanks Bruce – too many tabs open at once, or age. I prefer the former.
Yes, it does look like a Catherine wheel now that you mention it. Ha, that reminds me of that coriolis idea and rising magma plumes someone brought up during Eyjafjallajoküll.. who was it, was it Carl? (not saying that is the effect here, it just reminded me of it).
They seem to be doing better at public outreach than they did last time. Good on em!
Yes, I think so too. 🙂
Energy released to 12:56 today: http://oi49.tinypic.com/wb75nk.jpg
And count of EQs >4.0 mbLg
& the link: http://oi45.tinypic.com/ehdfmf.jpg
May i use this Karen. Please!!!
Hi Karenz and all,
I may have mentioned this, but thanks Karenz for sharing the cumulated energy plots; IGN don’t share these anymore and AVCAN, (with all due respect) tend to show them for the latest “series.” The overall accumulated energy (since July 2011) is actually the most informative; IMHAO.
another M 4.2 quake http://www.01.ign.es/ign/layoutIn/volcaListadoTerremotos.do?zona=2&cantidad_dias=10
Earthquake Report has a link to an image of all the spectrograms of this crisis stitched together:
Really good medium to compare the different phases up to now. Thank you, for linking that here in. 🙂
My pleasure 🙂
Thanks Jim and welcome to Volcanocafe,
Nice links; isn’t JDCV the same guy who made timelapses of BoB? Armand and Joke’s friend?
Is that the Hekla quake no. 8 whe have been waiting for? http://hraun.vedur.is/ja/oroi/mjo.gif and http://hraun.vedur.is/ja/hekla/borholu_thensla.html
no, likely the second and third quakes in Langjökull “new” location swarm I posted earlier
Or is it the 2nd quake on Kjölur (SE of Langjökull)? The same location as the last one, should be beneath the Kjalhraun shield volcano, I think. But probably part of southern Langjökull volcanic system. http://www.vedur.is/skjalftar-og-eldgos/jardskjalftar/langjokull/#view=table magn.2,4
yes, quakes there show quite well on all Hekla meters (all Langjökull area quakes in the past have done so, I guess because good transmitting rock situated inbetween), now these are rather shallow, think likely tetonic in nature, but true, its shield volcano there and on outskirts of larger “main system
Region we are talking about: the shield in the foreground is well discernable, in the middle ground you have Jarlhettur, hyaloclastic mountain range, and in the background the glacier shield of Langjökull. http://commons.wikimedia.org/wiki/File:Kjolur.jpg
Hekla had a another small raise bounce,
Local work going on?
At this stage I am confused, Is the yellow alert still on? If there is one, Why is it still on when most of abnormal data is getting longer and lower as time goes on.
Thank you all for the info and time for the site.
There is still yellow alert on Hekla and will remain untill next week. What yuo see is not Hekla related, some rather strong quakes at Langjökull, 2.4R, and storm waves are pounding the coastline (coarse looking strain) and such. Hekla is NOT stirring (yet).
I hope you have your mobile phone activated – “on slopes of Hekla”.
The Uncertainty level of Iceland’s Civil Defense is still valid http://en.vedur.is/#tab=skjalftar , but it seems the Aviation Alert level has been taken off.
One of the reasons for the first one could be that hiking in the mountains has become very popular in Iceland these last years and they intend to hold people a bit off the mountaineous interior, as not only Hekla is behaving in an unusual way, but also Askja, Bárdarbunga and Godabunga are rumbling. (just my personal opinion, no expert)
The Icelandic daily newspaper Morgunblaðið says that the alert level will be valid till after the Easter holidays and will be reevaluated beginning of next week (from Tuesday on as Monday is still a holiday). http://www.mbl.is/frettir/innlent/2013/03/27/ovissustig_endurskodad_eftir_paska/ They also repeat that nobody should venture on Hekla and that all people in the vicinity of the mountain will receive a mobile phone message in case an eruption is really imminent.
first time this co-incides with Easter Travel Season; going ontop glaciers and mountains on 4x4s this weekend is tradition – and after Eyjo, Katla, Grimsvötn “crises” and 6+ quake alert in north, possibly the AVR department becoming more cautious – but that can be more indicative of “Big Brother” tendency, rather than IMO becoming more smart or proficient in telling about possible events
Thank you Inge B and Islander for the follow up, Looking at the info to hand, could be Island wide changes below and extra pressure been placed on these volcanic area’s too.
I have never seen this dept EQ’S happening at the same time across 3 or 4 volcanic area’s.
fourth quake in that area, becoming a swarm or is this (far fetched) a possible runup sequence ????
You must be kidding! Leave your fellow countrymen one glacier at least to amuse themselves on during Easter holidays!
I mean there is still Drangajökull in the West Fjords area left, but that is a bit far to travel in a highweeler 4×4, consuming 20 l /100 km! 😉
Also – (a parte! – looks around to make sure nobody hears) – there is Daily Fail and such to consider!
@Spica; Just FYI, Please check your email\spambox. Sent yourself a email. 🙂
An image to remember the spectrogram of Bob starting eruption:
What VEI was Bob eruption classified?
😳 that was 1793.
Report on Bob:
With update at the end of this: http://www.volcano.si.edu/world/volcano.cfm?vnum=1803-02-&volpage=var#bgvn_3703
‘fraid Bob did not seem to get a grade.
Anyway thanks Karen.
I could imagine that submarine (only) eruptions never get a VEI due to 1) scientists being unable to know exactly about the exact volume of emitted lava and 2) there is seldom any damage done.
On the other hand, VEI seems to be a problem in itself, see eg. https://volcanocafe.wordpress.com/2012/04/10/why-the-vei-is-wonked/
Good Afternoon particularly to our Icelandic friends. Certainly this weekend is keeping us glued to the PCs . Avcan have psoted a continued warning from Pevolca for the people of El Hierro. They certainly are on the ball this time around and seem to be very positive in their communications. I am sure the locals appreciate this.
They have pinpointed roads and the tunnel closed due to possible landslides and have stated that the quakes are mving to the SW of the island and as yet are at a “safe” distance.
Islander you will need that drink tonight after all your watching. I agree the Langjokull quakes are odd. But then much of sub- Iceland seems to be moving. I remember a long discussion with Lurking and Carl ,way back, about the transfer of energy through the rocks and the possibility of a very complex “domino effect type thing” happening.
I know these various volcanic systems are not “related” as such but certainly something down there is stirring things this week……
Do they have Easter Bunnies burrowing or possibly Easter grabboids. 😀
I have easter egg, if my better part does not get at it before Sunday. Family dinner in few hours, so Hekla can do its bit in meantime (I do expect one farewell quake). Langjökull quakes likely tetonic only.
You driving at the same time as writing or what? I would watch out for speed cameras near Selfoss. 😉
Answer to “islander (now ) *far off slopes of Hekla*.