El Hierro

[jand]

1108809

30/10/2011

13:05:54

27.7698

-18.0398

22

Sentido

3.9

4

NW FRONTERA.IHI

[fifi]

One of the Islanders has contacted AVCAN saying that there are cracks visible in the Roquille tunnell. Many others are online saying that they can feel a constant tremor at the moment.

The Cabildo confirmed the tremors.

Cabildo de El Hierro
PrensaElHierro Cabildo de El Hierro
Again be felt in places like Frontera and Isora and El Mocanal, in the municipality of Valverde.
2 minutes ago

[jand]

This is from Madrid Science

JDR Henry it has stuck, look at what I said...

Volcanic actualidad de Canarias (AVCAN) I commented the matemático-sísmico problem I have is as follows, so that the curve of energies liberated seismically accumulated or "staircase of the devil" follow its evolution as it goes so far, what has to be is another earthquake equal or more stronger than this 3.9 before 12 h - 14 h.

With these data calculation this afternoon to that of the 18: 00 - 21: 00 h habra other / s near 4 or just skip to the next step of energies to 4.3-4.4 and that is a problem.

My personal recommendation, please do not use the Roquillos tunnel and take adequate measures for strong earthquakes, removing weight of the upper shelves, boxes, pots and everything that can fall. (Henry)

[fifi]

PrensaElHierro Cabildo de El Hierro
Council authorities are in constant contact with the leadership of PEVOLCA.
2 minutes ago

[jand]

eruptionsblog Erik K / Eruptions
From the sound of it, we might be looking at new eruptions at El Hierro soon. I'll post info as soon as I can get any confirmed activity.

pabloj_gonzalez Pablo J. González
@eruptionsblog Seismicity depth is really deep. Deeper than before, but perhaps maybe no a clear indicator as we testified at 1st eruption.

eruptionsblog Erik K / Eruptions
@pabloj_gonzalez Yeah, it doesn't seem clear what is going on ... Other than increasing tremor, inflation on the north and EQ size.


teideano teideano
Amazing shake right now!!! OMG, the whole road jumped as i was doing some measurements!!
32 minutes ago

[jand]

Fifi do you know if this is correct?


That latest 3.9 occurred 69km south of S Los llanos de aridane in La Palma. This town is centrally located on La Palma. Its a great reference point.

[fifi]

I dont know jand but the Islands are very near each other so it probably is.

[jand]

Owing to the increase in sismicity in the north of El Hierro, the Director General of Safety and Emergencies is moving to the Island this evening to evaluate the situation with the Scientists and Civil Protection authorities.

http://www.01.ign.es/ign/resources/volcanologia/txt/boletin_HIERRO.txt

Reply

[fifi]

I checked some of  the papers again and there is no mention of any new findings from the Ramon Margalef in them that I can see.

[SurfJames]

jut been looking at some of the photo's of the island - what a beautiful place.

[SurfJames]

There has just ben a second tremor of 3.9 this afternoon, in the NE of Frontera.

El Instituto Geográfico Nacional (IGN) ha registrado un nuevo movimiento sísmico de 3.9 grados de magnitud en la escala de Richter, según recoge la última actualización de la web del Instituto. Este movimiento sísmico se detectó a las 13:05 horas en el noroeste de Frontera y a una profundidad de 22 kilómetros. Con éste, ya son dos los sismos de 3.9 grados de magnitud registrados este domingo en la zona norte de la isla de El Hierro

[fifi]

It looks lovely allright. [] The pic above shows the location of that earthquake Surfjames. It is quite close to the coast.

[jand]

SurfJames is this correct or is it just crazy talk?

OOOh mylanta! Energy accumulaation making crazy rapid spike!, on this chart the energy doubled in the last 8 hours. on this one...the total enery has spiked significantly. [link to www.01.ign.es] 1.54E+12 we're now at an equivelent of 1541 tons of TNT. That is 3,082,000 pounds of TNT [link to www.online-unit-converter.com]

[fifi]

Yes it is right jand. The first one was around 7am and the second at 1pm.

[SurfJames]

I think there will be a second under water erruption tonight, north of the island.

[jand]

Fifi

This is very worrying then that sounds like a lot of explosives to me.

Everyone is talking about the pressure how it has rising today and still rising they say its like a pressure cooker and eventually will just explode.

We are talking though about magma and how its building up under the island surely all these earthquakes have also unsettled the ground under El Hierro and will have made it more unstable.

I hope the big wigs were not just thinking that this would go away and have been caught napping because this could now in IMO turn into something very serious indeed.

[jand]

SurfJames

The man from Madrid Science has also said he thinks sometime after 1800 tonight there will be an eartquake of 4.3 or above because of the rising pressure.

[fifi]

I will have a look later and see what the outcome of the meeting is. I dont think that anyone at this stage is able to confidently predict the outcome. My guess would be the same as Surfjames....another submarine eruption.

[jand]

Data Update 30/10 – 14:12 UTC
 Seismic activity remains strong. Another magnitude 3.9 earthquake occurred at 13:05 UTC (14:05 local time). This earthquake was well felt on different parts of El Hierro. Another concern is the accumulated energy? Click here to see the graphic? The continuing strong earthquakes is pushing the graph higher. Deformation graphics on the other hand are relatively stable.

[SurfJames]

There is a similar pattern to the first erruption, so I made a guess that it would errupt tonight.

There's a lot of talk about the pressure building up - which I don't really understand. I guess the magma needs to find a way to the surface, and the pressure forces it through existing faults in the ground.

I did read that there is a risk of a tectonic shift if the pressure gets too high, which will result in a more powerful earthquake, but this is only conjecture.

I hope that the residents of the Island are not suffering to much from anxiety. The general impression from various experts is that the risks are low.

What was felt in Las Palmas..out of interest? Was it a quake under/near that Island, or the same one felt in El Hierro?

[jand]

Translated from Spanish

Outstanding border
The surge of seismic activity in border has resulted in increased vigilance in this area of the island. While the eruption of La Restinga continues without any news, where the pressure of the system has declined since then, now the increase in seismicity has moved again to border, which began last July.






DIARIOELHIERRO.It is, drafting (10 30, 2011 15: 22 hours.) (Information updated at 16: 32)
The surge of seismic activity in border has resulted in increased vigilance in this area of the island. While the eruption from October 10 continues in the funds of La Restinga, where the pressure of the system has declined since then, now the increase in seismicity has moved again to border, which began last July.
It reported this afternoon the Pevolca the evolution of seismicity in the North of the island has increased in recent days and the scientists, who are constantly monitoring, shuffled all possible scenarios, but still can not defined with sufficient precision.
In this sense, incline between the main options the process decreases or evolve towards an eruption * located, most likely, in the sea, with the characteristics of which is being developed to the South, whose parameters remain stable.
Today already are two 3.9 earthquakes registered in El Hierro, a fact that has not altered by the time the level of warning earthquake on the island, which is at yellow lights with red and general character for the area of La Restinga.
Scientists are inclined to the recent quakes are of magmatic origin and tectonic not and now is follow its evolution.
For the moment have not adopted further measures for the population, but it is possible that the Roquillos tunnel again to close if continues to increase the intensity of seismic movements. The population should remain quiet and attentive to the events, said Juan Santana.
Discuss this news in the newspaper EL HIERRO Facebook. CLICK HERE.

[jand]

The mag 3.0 plus quakes were all at 22km yesterday, in NW Frontera, and the plus 2.0s at 16km. Latest are mag 3.0 plus at 19km and plus 2.0 at 15km.

So if this is the large ball of magma which Carracedo identified on 29 September, then Peter, you are right that no magma has risen above the crust at 14km, yet, other than what is already closer to the surface in other magma chambers, and extruding south of El Pinar and Restinga.

But if this heat is rising through the sedimentary layer, and has already reached the surface in El Golfo, then would it not be accurate then to expect that the magma will follow? And that there is a lot of it on its way.

Also – if it breaches the sedimentary layer may it not split along the rifting, and cause a large seismic quake at the surface? And a subsequent eruption too to follow?

Is this what you are suggesting, Jon?
 The logistics of evacuating people where roads are not well developed need to be addressed sooner rather than later.

Reply

[jand]

Copied from Avcan

Translated from Spanish.

I've heard in the news of tve which is likely a volcanic eruption in border and that if so, is would evacuate the population. Happened to me, that suddenly I've become aware of the situation and not for the very expected, has been less shocking news. Suddenly, there were two scientists saying what feared us some days ago and that on the other hand they have stubbornly refused until yesterday.
10 minutes ago · Like · Original.


Francis De La Rosa #8206;"there can be an eruptive process in the North of the island" this sentence lends itself to confusion... I I know my people...
9 minutes ago · Like · Original


Paco Rodríguez I think that there is fear among the authorities, and perhaps among the scientists to get wet in shuffle with a high level of certainty that can now have a new eruption in a more densely populated area, and what they is the dramatic of the measures taken. Gentlemen, the first thing is the people, and if all the means taken to act on a possible emergency situation in El Hierro showed us in his day, what expect?
7 minutes ago · Like · 1 person · Original.


Cadena Cope Tenerife At 19.00 h held a meeting of the PEVOLCA to analyze the increase in Seismicity in the NW area of the island. At this meeting, in principle, it is not expected to adopt new measures of prevention.
Security measures could decide at the meeting that the Executive Committee of the PEVOLCA plans to develop tomorrow. The start time of this meeting has not yet been set by the authorities.
about a minute ago · Like · Original

[jand]

The National Geographic Institute has confirmed this morning at the direction of the Civil Protection Plan for Volcanic Risk (Pevolca) a magnitude 3.9 earthquake struck northwest of Frontera, located in the sea at a depth of 22 miles deep. The earthquake was followed by a 3.2 magnitude aftershock which struck at a depth of 19 km. The quake, which was felt by the population, occurred at 07.46 hours and is the largest earthquake recorded in the island after the onset of the eruption south of La Restinga. The Emergency Coordination Center and Security (CECOES) received 1-1-2 calls from the towns of Isora, Guarazoca, Mocanal (Valverde) and Tigaday (Border). The evolution of seismicity in the north of the island has increased in recent days and scientists, who are monitoring constantly all possible scenarios, still cannot ascertain what this new activity means. In this sense, they are inclined to believe that this new activity could be producing a seamount. Moreover, those responsible for the IGN have confirmed that yesterday, 62 earthquakes were reported along this region with two of them being felt by the population. The earthquake of greatest magnitude in yesterday's swarm reached a magnitude of 3.6 on the Richter scale. This movement has been located at sea in the Gulf area about 4 miles from the coast at a depth of 23 kilometers. It has been felt by the population with maximum intensity IV in the town of Valverde. The depths vary between 15 km and 25 km. In total, since the day July 17, 2011, the island of El Hierro has been shaken by more than 10, 615 earthquakes. According to reports from scientists at the University of Cadiz, and with reference to the deformation of the ground, this continues in two separate scenarios. The south of the island shows a remission in increasing deformation, clearly marked by the eruption process and that is evident in the data recorded in the GPS station of La Restinga. However, in the north of the island, there is an increased component of deformation component to the North and the East.

 [link to www.europapress.es]

[jand]

Seamount


From Wikipedia, the free encyclopedia


A seamount is a mountain rising from the ocean seafloor that does not reach to the water's surface (sea level), and thus is not an island. These are typically formed from extinct volcanoes, that rise abruptly and are usually found rising from a seafloor of 1,000–4,000 metres (3,281–13,123 ft) depth. They are defined by oceanographers as independent features that rise to at least 1,000 metres (3,281 ft) above the seafloor. The peaks are often found hundreds to thousands of metres below the surface, and are therefore considered to be within the deep sea.[1] There are an estimated 100,000 seamounts across the globe, with only a few having been studied. Seamounts come in all shapes and sizes, and follow a distinctive pattern of growth, activity, and death. In recent years, several active seamounts have been observed, for example Loihi in the Hawaiian Islands.

Because of their abundance, seamounts are one of the most common oceanic ecosystems in the world. Interactions between seamounts and underwater currents, as well as their elevated position in the water, attract plankton, corals, fish, and marine mammals alike. Their aggregational effect has been noted by the commercial fishing industry, and many seamounts support extensive fisheries. There are ongoing concerns on the negative impact of fishing on seamount ecosystems, and well-documented cases of stock decline, for example with the orange roughy (Hoplostethus atlanticus). 95% of ecological damage is done by bottom trawling, which literally scrapes whole ecosystems off seamounts.

Because of their large numbers, many seamounts remain to be properly studied, and even mapped. Bathymetry and satellite altimetry are two technologies working to close the gap. There have been instances where naval vessels have collided with uncharted seamounts; for example, Muirfield Seamount is named after the ship that struck it in 1973. However, the greatest danger from seamounts are flank collapses; as they get older, extrusions seeping in the seamounts put pressure on their sides, causing landslides that have the potential to generate massive tsunamis.

[jand]

Latest Message From Avcan.

Translated from Spanish.

Given the current situation to the North of the Gulf, AVCAN recalls the self-protection measures before seismic risks and volcanic eruptions.


In previous situations, these recommendations were especially focused on the population of El Pinar, especially to La Restinga, but due to seismic activity which took place in the last days, and especially today, we strongly recommend to all the inhabitants of the Valley of the Gulf (and the island of El Hierro as a whole), read carefully these recommendationscompiled from different estates officers: General Directorate of Civil Defence and emergencies (State), Government of the Canary Islands and Cabildo Insular of iron.


Please stay tuned to all official releases in the coming hours, days can be issued, and that for the sake of the community, follow the instructions that can be decreed.


I encourage all the Islanders. AVCAN has been, is and seguírá being with you (Heriberto Lorenzo)

[fifi]

The Government press release after the meeting with PEVLOCA http://www.gobcan.es/noticias/index.jsp?module=1&page=nota.htm&id=144271

Synopsis....the increase in seismicity does not require any extra civil protection measures, we will keep an eye on this because it could be a tectonic settlement,seismicity is occurring too deep and there are no other precursors, such as variations in ground deformation to show that there is an imminent eruption,follow more closely the seismicity is occurring at less depth, although less frequent and smaller in magnitude, is what might be indicative of an eruptive process, the current situation does not at the moment pose a risk to the polulation.They will be vigilant.





               ...........................
 Islanders left messages on the IGNs facebook page in disgust with the way they are being kept in the dark about the situation.They can see more with their own eyes than they are being told by Scientists and Politicians and are very frustrated. The majority are up in arms about one station in particular H104 with many messages the same...¿ QUÉ PASA CON LA HI04? They know that incorrect data is  being used and feel that they are being treated like fools.

             ....................

AVCANs response to the Governments statement

Current Volcanic Islands (AVCAN) The most incredible part of this note "that the increase in the magnitude of the seismicity recorded Frontera today may be a tectonic settlement of the land, caused by the eruption is occurring in the south of the island "

I have not seen settlements to rise in magnitude and less at that depth. And I say, if a volcanic eruption, is tectonic? if tectonic, why there is a volcanic eruption?

              .................

Hi Surfjames, I didnt read anything about La Palma today but didnt manage to read everything. What was happening there?

[jand]

Different points Of View      www.jonfr.com/volcano.

Avcan have yesterday been quoting from this site.

This is a rift eruption. Earthquake swarms are not going to happen without magma being on the move. In most cases there is going to be a eruption following that. It is impossible to know where a eruption vent might open up, and when for that matter.

When this blog post was written a harmonic tremor pulse had started to appear on the tremor plots. They have continued to happen all day (from 10 to 30 min at the time). This means that magma is on the move. The growing earthquake swarm is also clear sign of this movement of magma. As the magma is looking and breaking a path up to the surface this moment.

The problem with fissure type of eruption is where they are going to show them self. For that reason I rather want to get thing wrong then right in regards to El Hierro Island. Since the population is at risk in my view from this eruption in El Hierro volcano.

Reply


Pieter says:

 October 30, 2011 at 23:31


Thank you for ellaborating. This clears things up.
 I still wouldn't speak of real signs of a new eruption vent. This could just as well be a plutonic intrusion or just another blob of magma feeding the already open vent.
 Also, rather get things wrong then right seems kinda weird to me? What did you mean?

Reply


Carl le Strange says:

 October 30, 2011 at 23:41


Pieter, he meant that it is better to err in the way of caution, then being wrong in a fatal way. I think IGN is risking being wrong in the fatal way. But on the other hand, they have changed their minds again.

Reply





KarenZ says:

 October 31, 2011 at 03:07


But there is some support for Jon's argument.

1) Bob is described by the authorities as a fissure eruption.
 2) There were very few EQs, if any, preceding Bob at the site Bob erupted.
 3) There has been shallow EQ activity in the El Hierro area, if you look at the whole period from 19/07/2011 (a very short geological time span).
 4) The time line of EQ activity was Frontera to El Pinar prior to the eruption of Bob. EQ activity virtually stopped for a short period prior to Bob in Frontera (but that period again was very short) before resuming again – this time at a lower depth but stronger.
 5) EQs activity and accumulated energy is rising again.

The supporting data is readily available on IGN and avcan.org websites (on the latter you can watch the animation of EQs from the start of the swarms to today).

Far better to look at the facts. Because whether Jon is correct or not, something is happening and the signs are not good at the moment.

The authorities need to make sure that they can evacuate the island fast if they have to – emphasis on fast. Evacuation and small eruption is just inconvenient compared to the failure to evacuate in time in the event of a larger eruption that leads to casualties. Not an easy decision but far better now to err on the side of caution, assuming that the worst will happen.

Reply

[jand]

Already they have had 22 earthquakes since midnight this morning.

Quoted on Avcan Facepage

Movidito night, 22 earthquakes until the four quarter, many more than the 5 that is had registered yesterday at that time. Remarkable is that of 3.4 on the two in the morning, probably meaning.
about an hour ago · Like · 1 person · Original.

For confirmation view

http://www.ign.es/ign/layoutIn/volcaListadoTerremotos.do?zona=2&cantidad_dias=10

[jand]

Magnitude ML 3.1
Region CANARY ISLANDS, SPAIN REGION
Date time 2011-10-31 07:13:12.2 UTC
Location 27.78 N ; 18.04 W
Depth 22 km
Distances 186 km SW San cristóbal de la laguna (pop 139,928 ; local time 07:13:12.2 2011-10-31)
98 km S Los llanos de aridane (pop 19,635 ; local time 07:13:12.2 2011-10-31)
79 km SW Valle gran rey (pop 4,983 ; local time 07:13:12.2 2011-10-31)