Earthquake Swarm (11000+) El Hierro, Canary Islands

je55ie

maquiladora wrote: »

The harmonic tremor has started to go "off the scale" since about 7am this morning. You can see at the top of the spectrogram, the blue has turned into more of a solid block over the last couple of hours, indicating that the peaks are higher than what can actually be depicted.

Can you explain what this might mean?

maquiladora

jessie37 wrote: »

maquiladora wrote: »

The harmonic tremor has started to go "off the scale" since about 7am this morning. You can see at the top of the spectrogram, the blue has turned into more of a solid block over the last couple of hours, indicating that the peaks are higher than what can actually be depicted.

Can you explain what this might mean?

Could be that a new vent will open somewhere or if might just be a more intense phase, will have to wait and see if it drops again.

je55ie

:eek: Looks crazy , lets hope it dies down for the people of El Hierro. Must be a nerve wrecking time for them.

cherryghost

Interesting on the other volcanic island, La Gomera, there was a few shakes on its seismogram prior to this 'awakening' on El Hierro. Since El Hierro started yesterday morning, there hasn't been a shake from it. HOWEVER, its started to pick up those tremors from El Hierro. It's highly unlikely, but is there a fraction of a chance El Hierro could trigger this?

maquiladora

Enderman wrote: »

Interesting on the other volcanic island, La Gomera, there was a few shakes on its seismogram prior to this 'awakening' on El Hierro. Since El Hierro started yesterday morning, there hasn't been a shake from it. HOWEVER, its started to pick up those tremors from El Hierro. It's highly unlikely, but is there a fraction of a chance El Hierro could trigger this?

Gomera is just detecting the tremor from El Hierro since it is not too far away. I haven't seen any diagrams showing the El Hierro plumbing system connected to Gomera so I don't think there is any chance of it triggering anything there.

cherryghost

From Twitter:

teideano



@eruptionsblog some reports of felt tremor by some....ok, really prelimianr and needs confirmation, but if felt, then we have a problem.

Meanwhile the intensity is still increasing, the charts are almost unreadable close up now. Best bet is to keep an eye on the 24 hour chart and see if it ups the ante or not. There was a few lulls this morning, both of which ended with an increase in intensity than prior to the lull.

cherryghost

141_Oscar_Mike wrote: »

Via Twitter..

Whose Twitter account was that tweeted from?

je55ie

Evacuation under way in El Hierro

cherryghost

Was just about to say, yep. El Hierro is now under evacuation process.

teideano



@eruptionsblog Evacuation under way in El Hierro, evacuation under way in El Hierro. Magma migration should be inland.

cherryghost

Bit of false information on Twitter's behalf, only La Restinga is being evacuated, more than likely to the east of the Island.

maquiladora

From what I have seen from AVCAN, it is just the population of La Restinga that is being evacuated. I've seen a figure of 600 mentioned. It seems to be due to fears of the possibility that of new eruption areas closer to the coast or maybe even on land.

cherryghost

So the tremor felt an hour ago is confirmed here (video of shaking table in La Restinga). The reports of the tremors sent the officials to evacuate the area ASAP

Cathmandooo

I'd have thought there would be more shaking than in that video! My water bottle beside my keyboard is shaking just as much while I type :pac:

Do you think they will evacuate the whole island but are concentrating on the La Restinga as it's most likely to be near any inland eruption?

cherryghost

Cathmandooo wrote: »

Do you think they will evacuate the whole island but are concentrating on the La Restinga as it's most likely to be near any inland eruption?

Well the patterns of the quakes since July have been of southwards one. However some recorded tremors and quakes have been closer to land in the last 12 hours. Better safe than sorry though. A complete island evacuation is not on the cards if it continues underwater.

The eruptive history of El Hierro isn't much of an explosive one either so even if we had some eruptions on land it'd be nowhere near the activity of the Icelandic volcanoes. Landslides are more of a concern and anywhere east/northeast of the island is more than safe safe unless something completely out of the blue change of pattern emerges.


EDIT: AVCAN has confirmed the island is now on RED ALERT (I love having a Spanish tongue wife )

maquiladora

I've seen some speculation that the eruption may not have actually started yet and that what happened yesterday under the sea off the coast was just a release of gases & not magma (hence the dead fish, but no big earthquakes).

We could still see an euption on the island itself.

maquiladora

It is only the La Restinga area that is now Red on the traffic light system, but that could change as this progresses.

maquiladora

The tremor is still going strong.

This is the latest from the local media : (translated)

16:28 The epicentre of the latest earthquakes moves toward the center of El Hierro. The National Geographic Institute expects earthquakes of greater intensity - between 4 and 5 degrees - under the pressure of the lava in search of a new point of departure.

maquiladora

http://foro.tiempo.com/index.php?action=dlattach;topic=135081.0;attach=180320;image

Not sure where this came from, but it is a comparison between the harmonic tremor before the Mount Shishaldin, Alaska eruption (1999 I think) to the current harmonic tremor at El Hierro.

Now I'm sure it probably isn't right to compare the pattern between two different volcanic systems since every volcano is different, but if you compare the "red" areas and how high they reach in terms of Hz, then the amount of energy in the current El Heirro tremor would lead to a VEI 4+ eruption, if it was happening at Shishaldin.......

Edit : Local media A3Canarias is tweeting an eruption is "imminent" and could happen tonight. Don't know what their source is though.

Elmo5

It's looking like a new canary island being born isn't it?

maquiladora

Some more info from the local news media there.

11/10/2011 20:42 – Joan Martí, a researcher at the CSIC (Instituto de Ciencias de la Tierra) and secretary of the ‘Asociación Internacional de Vulcanología’ (International association of vulcanology) has stated that “As the magma approaches the coast of El Hierro, it could trigger an explosive eruption if it occurs at a depth of less than 200 metres but would not be dangerous if appropriate safety measures are taken”. It is thought that the magma could be following a fault under the sea bed which is known to run underneath the island and could currently be looking for another way to escape to the surface. Scientists have observed that the magma is currently moving towards the centre of the island.

Meanwhile, the tremor is still ongoing as strong as ever.

maquiladora

The tremor seems to be getting more intense over the last couple of hours. It's hard to see on the El Hierro chart because the tremor is too strong for the instrumentation/parameters and it is" clipping" /going off the chart. But looking at nearby stations on some of the other islands, you can see more clearly that the distant tremor has become more intense.

The magma is moving and looking for the easiest route up, it doesn't care if that is at sea or on land. If it cannot find an easy route then it will blast its way up and there could be some big earthquakes, but at least that will give some warning of where it will happen.

Jon Frimann has pointed out that there have been new deep earthquakes today which indicates even more magma is rising up.

donzenettii

I feel sorry for all the people on the Island, I can't imagine being evacuated from my home and left wondering if it is going to just slide into the sea,

cherryghost

Indications on the charts at the moment is that tremor activity is beginning to ease a little. Wait and see if it starts building again soon though.

Harps

Enderman = Cherrygoast?

Certainly an interesting situation at the moment, not been picked up by the mainstream media yet but it seems to be getting more serious the longer they don't know where the main eruption will take place

cherryghost

Harps wrote: »

Enderman = Cherrygoast?

Certainly an interesting situation at the moment, not been picked up by the mainstream media yet but it seems to be getting more serious the longer they don't know where the main eruption will take place

Yeah sorry, name change this morning

maquiladora

Enderman wrote: »

Indications on the charts at the moment is that tremor activity is beginning to ease a little. Wait and see if it starts building again soon though.

Yes, hard to see much change on the El Hierro spectrogram but from the "view" on the other islands it looks like the tremor has eased back down to the level it was at earlier this evening, but its still very high.

But it's at a stage now where a new eruption event could happen with little or no warning at any moment.

I don't think I'd be able to sleep tonight if I was living on El Hierro. :eek:

cherryghost

Good 3D model of the island and beneath water surface



Also the tremor progessions since the harmonic tremors began



Still off the scales currently but its actually not as intense as it was.

Also, the accumulated energy down there has levelled off. Still a massive 1.3 TRILLION joules. One wonders what these new deep quakes will do though, pushing up magma and increasing the energy, unless the current tremors give way to something beforehand

gbee

Type: Earthquake
3 hours ago
Magnitude: 2.6
DateTime: Wednesday October 12 2011, 08:41:41 UTC
Region: Canary Islands, Spain Region
Depth: 14 km
Source: CSEM-EMSC Feed

http://quakes.globalincidentmap.com/map_detail.php?id=138812

Also notice the 'line' of earthquakes Canary Islands, Spain, Germany, Estonia

maquiladora

The tremor is still ongoing, but it is a bit weaker than it was last night.

No major developments.

cherryghost

Tremors have been up and down today. Quitening down for a short period before bursting into more powerful tremors. Accumulated energy has started to rise slowly once again.