General Volcanic Activity Thread!

[Crepuscular Ray]

The harmonic tremor increased dramatically overnight:

http://www.ign.es/ign/head/volcaSenalesAnterioresDia.do?nombreFichero=CHIE_2011-10-11&ver=s&estacion=CHIE&Anio=2011&Mes=10&Dia=11&tipo=1

According to El Mundo, there has been magma released but it is being kept on the sea bed by water pressure; there has also been some reduction in ground deformation.

http://www.elmundo.es/elmundo/2011/10/10/ciencia/1318281564.html

[yamkin]

LAPROVINCIA.ES The National Geographic Institute (IGN) ensures that the tremors that herald the eruption of El Hierro are on the rise since last Monday at four am.

According to volcanologist Rafael Abella, this type of earthquakes associated with magma indicate the greater proximity of magma to the surface materials, and an imminent eruption.

At 17.00 hours on Monday is scheduled to meet members of PEVOLCA (Special Plan of Civil Protection and Emergency Risk-volcanic)...................http://www.laopinion.es/sociedad/2011/10/11/magma-hierro-empuja-vez/373594.html

[GulberwickWeather]

Amplitude of the tremor still increasing. Looks like something could go 'bang' fairly soon if this keeps up........

http://www.ign.es/ign/head/volcaSenalesAnterioresDia.do?nombreFichero=CHIE_2011-10-11&ver=s&estacion=CHIE&Anio=2011&Mes=10&Dia=11

[toggerob]

They are starting to evacuate La Restinga as a precaution. I guess the authorities aren't taking the risk that a next fissure opening could potentially be ontop of the town, given it sits right next to a dormant volcanic vent.

[GulberwickWeather]

Indeed. It does look like somethings building. The trace on the webicorder has got to the point where its being 'clipped'.

Media report on the evacuation of La Restinga states Alert Level now at 'Red'

http://www.diariodea...cua-la-restinga

According to the babelfish translation the population of La Restinga have been told to report to the football ground to prepare for evacuation.

Edited October 11, 2011 by GWW

[yamkin]

Reports are coming in that the Canary Island government has raised the alert level to RED

Urgent-light has been raised to red volcanic risk. The president of the Cabildo de El Hierro, Alpidio Armas, has confirmed to Radio Onda Cero that the light Teide alert level has been raised to red.

GWW, Hope you don't mind me adding this info too?

Edited October 11, 2011 by yamkin

[GulberwickWeather]

Check out this graph from IGN (Instituto Geofisical Nacional) from the webicorder on El Hierro. As you can see at the very top the webicorder trace is now almost a solid blue line indicating that the amplitude is such that the signal is being 'clipped' to prevent it scrawling all over the graph. More worryingly look at the table below which shows the frequency range of the tremors. As you can see they start more in the 'narrow band' 2-3 Hz range, which can be indicative of a VEI2 eruption, but they seem to be more and more in the 4-6Hz 'broadband' range now which could be indicative of a VEI3-4 eruption.

http://www.01.ign.es...0&Dia=11&tipo=2

Heres a piece which describes how the frequency of the quake signal can relate to the VEI - thanks to Andy Scollick over at Eruptions for this:

http://img51.imageshack.us/img51/4219/tremoresmodelo2.jpg

Edited October 11, 2011 by GWW

[karyo]

Thanks for all the updates guys.

Are there any webcams from the area so that we can see if there are any visible signs of the eruption?

Karyo

[GulberwickWeather]

None that I've come across karyo. It appears from the chat over at Eruptions that whats happening is this has started as a submarine eruption and this is now unzipping a fissure which is getting close to the island, hence the evacuation of La Restinga.

[yamkin]

Thanks for all the updates guys.

Are there any webcams from the area so that we can see if there are any visible signs of the eruption?

Karyo

Hi Karyo, There is a web cam, but the El Hierro area is blacked out. Here it is anyway, just scroll to the bottom. You never know, it may start working again!! http://personal.tele...amscanarias.htm

The vibrations here are amazing and worrying http://www.01.ign.es...0&Dia=11&tipo=1

Edited October 11, 2011 by yamkin

[GulberwickWeather]

That cam at Las Puntas does seem to work occasionally Yamkin but it keeps coming up with a "temporarily overloaded" message. Looks like you're not the only one to have found it!

Edited October 11, 2011 by GWW

[karyo]

Hi Karyo, There is a web cam, but the El Hierro area is blacked out. Here it is anyway, just scroll to the bottom. You never know, it may start working again!! http://personal.tele...amscanarias.htm

The vibrations here are amazing and worrying http://www.01.ign.es...0&Dia=11&tipo=1

Thanks Yamkin,

so annoying that it's not working!

Indeed, the eruption seems to be intensifying!

Karyo

Edit: Looking at the various webcams brings me memories of my holidays in Tenerife and Gran Canaria! I wish I was there now! lol

Edited October 11, 2011 by karyo

[Habsish]

Why if there is so much activity are the earthquakes not shown on something like http://quakes.globalincidentmap.com/?

[GulberwickWeather]

There seems to have been a step-change in this eruption since about 6am this morning. Notice from the spectral plot and indeed the webicorder trace how everything got more intense from then. Also note the yellow streaks going from bottom top, those are earthquakes. Notice how before 6am they were only getting about 2/3 the way across the plot, now they are right to the top.

http://www.01.ign.es/ign/head/volcaSenalesAnterioresDia.do?nombreFichero=CHIE_2011-10-11&ver=s&estacion=CHIE&Anio=2011&Mes=10&Dia=11&tipo=2

[Martin M]

In reply to Habsish, the quakes are too small to register on that, i think only the small ones in USA are registered on these types of site.

Edited October 11, 2011 by Martin M

[GulberwickWeather]

Incidentally folks, AVCAN have a Facebook page. Obviously its all in Spanish but worth translating and following.

https://www.facebook.com/pages/Actualidad-Volc%C3%A1nica-de-Canarias-AVCAN/163883668446

[yamkin]

Thanks Yamkin,

so annoying that it's not working!

Indeed, the eruption seems to be intensifying!

Karyo

Edit: Looking at the various webcams brings me memories of my holidays in Tenerife and Gran Canaria! I wish I was there now! lol

The pictures from the web cams are beautiful. Let's hope the beauty remains. we also have to watch Katla. Some tremors today as well.

[GulberwickWeather]

According to a guy (Enrique) at AVCAN on their FB page, the data indicate a likely VEI2-3 eruption.

[Martin M]

This plot has been posted on Jon Frimanns blog, http://i56.tinypic.com/v2tvyp.png . Now if im reading that correctly then it wont take much movement of the fissure to come a lot closer to the surface of the ocean. The depth of the vent is marked up at 600m.

So if they are fearing it moving towards the island, it wont take long till something can be seen from above.

Edited October 11, 2011 by Martin M

[yamkin]

The intense heat prevailing in La Restinga requires paying attention to some displaced people to the football field, especially the elderly. The president of the Cabildo El Hierro, Alpidio Armas, is on the football field with neighboring La Restinga. He says there is a real risk of eruption on the ground.

[karyo]

The intense heat prevailing in La Restinga requires paying attention to some displaced people to the football field, especially the elderly. The president of the Cabildo El Hierro, Alpidio Armas, is on the football field with neighboring La Restinga. He says there is a real risk of eruption on the ground.

I wonder where this heat is coming from as according to the weather forecast, the maximum temperature in the island today is 26c http://www.wunderground.com/global/stations/60001.html

That's not considered that hot by the locals who are used to much higher temperatures!

I visit the Canaries often during the winter months and the temperatures are often higher than 20c even in January and the locals wear long sleeves as for them it is on the cool side.

Karyo

[yamkin]

I wonder where this heat is coming from as according to the weather forecast, the maximum temperature in the island today is 26c http://www.wundergro...ions/60001.html

That's not considered that hot by the locals who are used to much higher temperatures!

I visit the Canaries often during the winter months and the temperatures are often higher than 20c even in January and the locals wear long sleeves as for them it is on the cool side.

Karyo

Looks like the heat is coming from the rising magma

IGN reports an earthquake at 15:39 hrs, 2.0 degrees at 12 km depth

[toggerob]

I'm useless with trigonometry (I think that's the definition) but Martin M's link to the fissure profile doesn't look great, considering the inclination of the slope the magma is heading towards inland. Any external pressure forcing outwards could easily lead to a slide of that escarpment. Going to have to try my best a 101 trigonometry mathematics before this thing goes..unless anyone with better skills can try to have a go.

[Martin M]

I'm useless with trigonometry (I think that's the definition) but Martin M's link to the fissure profile doesn't look great, considering the inclination of the slope the magma is heading towards inland. Any external pressure forcing outwards could easily lead to a slide of that escarpment. Going to have to try my best a 101 trigonometry mathematics before this thing goes..unless anyone with better skills can try to have a go.

Yeah, I have those fears too, apparently those escarpments are 200 thousand years old so id imagine would be quite compacted by now, if that makes a difference i don't know, but it doesnt look good for an area known for major landslides.

And heres a high detail map of the island with all the known craters marked on it http://img835.imageshack.us/img835/2751/geology96.jpg

Edited October 11, 2011 by Martin M

[GulberwickWeather]

AVCAN are saying that the earthquakes are expected to become stronger in the coming hours and that they are moving more towards the interior of the island. The Red Alert/evacuation at the moment only applies to the southern part of the island around La Restinga but this could change.

As you can see from the plot the quakes from 2 days ago are in green, the quakes from yesterday are in red/orange and todays are in blue - shows a migration towards the main island. The most recent quakes have a mag of 2.7 and 2.4

http://www.avcan.org/mapas/AVCAN1363.jpg?d=1318351247

Edited October 11, 2011 by GWW