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.
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
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:
To 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.
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.
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