Tirelessly updating Avalon on the El Hierro eruption.

[Hervé]

Strongest so far (3.7 at 15:32):

For the day:

Frequencies spectrogram, the vertical streaks indicate “events” (tremors/EQs) whereas the horizontal ones reflect volcanic/magmatic activity:

From Wikipedia: A Harmonic tremor is a sustained release of seismic and/or infrasonic energy typically associated with the underground movement of magma and/or venting of volcanic gases from magma. Being a long-duration continuous signal from a temporally extended source, a volcanic tremor contrasts distinctly with transient sources of seismic radiation, such as tremors that are typically associated with earthquake and explosion.

How it's looking like now from Las Puntas de La Frontera:

Refresh your browser to get the latest traces

For the last 10 days, following the count of EQs as shown by the orange bars (≥ 2.0), it now shows whatever Polly is up to as far as seismic activity is concerned:

New cumulative graph starting October 10, 2011. The continuously changing scales keeps compressing the earlier graphs to the bottom and to the left!

Location of the EQs for the last 10 days:

Refresh your browser page to get the latest numbers and positions.

[Hervé]

Something just happened somewhere, hourly seismic tremor graph:

The intensity just suddenly decreased. Very similar to what happened on October 12, 2011; just before Polly's Jacuzzi began to appear:

This, following a renewed activity in the La Restinga/El Pinar area two hours earlier with a 2.3* which occurred at a depth of 17 kilometers here:

I think we are going to see Polly emerge out of her bubble bath soon...

See this article for the rationale behind these events: http://www.jonfr.com/volcano/?p=1816

* Last logged EQ by IGN for the day (November 17)

[Hervé]

Plume as seen from the Guardia Civil chopper on November 17:

[Guest]

Wow, wow, wow this has been an amazing unfolding for me -I have been glued to this thread for months now.

Hope everyone stays safe and the government handles the safety of the people in the best possible way.

Nora

we are all related

[sygh]

Posted by Amzer Zo (here)
Not much happened yesterday with a total of earthquakes lower than the day before.

The only thing of note is an intensification of the harmonic tremors up to saturation:

... which is also something that occurred right before Polly started bubbling in the open:

It looks just as intense as Poly only... deeper and, of course, more water pressure.
Just want to say, I am amazed at the graphs.
Prayers, as always.

[Hervé]

New 3D spatial rendering of the EQs for November from Geolurking (interesting preface to the animation):

Source: https://youtube.com/watch?v=86lP8-EkbPo

[Hervé]

Another take on the El Hierro situation from a La Laguna University geologist:

José Antonio Rodríguez Losada, Geologist and Professor, Department of Soil Science and Geology at the University of La Laguna.


We have the answers of Professor José Antonio, we particularly appreciate your generosity for providing detailed answers.

1 - I wonder which is the true, serious analysis of the Restinga coconuts, what are the components of these materials and if it can definitely be explosive or not?

Today (11/15/2011), analyses of both the black crust and the majority white material inside the coconut, popularly known as restingolitas, are available. Analyses have been carried out both by members of PEVOLCA and as personal initiatives of researchers outside the official Scientific body. In my opinion all tests have an "a priori" of credibility. I myself am in the process of receiving results of these samples from analyses carried out in accredited laboratories. Meanwhile, knowing that the surface has a black crust of basanite composition ("roughly" basaltic) and an extremely porous white material wiyh a typical composition of rhyolite. These are objective data.

Where is the controversy and why it exists?. The controversy revolves around the white stuff and why such controversy?. From the different interpretations derived from the composition which in turn have a very different implications depending on which interpretation is considered. These interpretations are 3:

a) origin from the fusion of siliceous sediments much older than the magmatic material from the oceanic crust. Such fusion is just induced by the basalt covering the white material,

b) is expanded perlite or volcaniclastic material also older than the magma issued and are also sedimentovolcanics fused but not necessarily of the oceanic crust

c) That the magma is actually rhyolitic and perhaps reactivated by intrusion of basaltic magma.

Additional evidence, mainly from geochemical analyses, are not yet available (or if you have not been shown any) but will confirm, in an objective and indisputable manner, which is the source of that magma or pseudomagma of rhyolitic composition.


2 - Is it safe to say that there will be an explosive eruption if it smells of sulfur as the sulfur, so far as I know, are coming out of the Teide and other explosive volcanoes, right?

No, you can ensure that no explosive phases occur only by sulfur or sulfur compounds. The sulfur compounds (sulfur dioxide, hydrogen sulfide ...) is common in gaseous emissions from volcanic systems in both pre-eruptive periods and post-eruptive. Other factors that may favor the volcanic explosion even with low viscosity magmas and associated with little or no explosive such as basalt. A decisive factor is the presence of large masses of seawater or groundwater near the eruptive conduit and the hydrostatic pressure is sufficient (exceed magmatic pressure) to inject quickly through the phases and produce magmatic explosive eruptions characteristic of hydromagmatic . This is what must be taken into account when weighing the risk of explosive events. However, it should be noted that if the interaction of magma with water occurs under a water column higher than 100 meters, the high hydrostatic pressure (about 1 MPa) can inhibit the explosive expansion of water and therefore significantly reduce the risk of explosive phases.


3 - You know the Hawaiian volcanism well; do you see any similarity of this process in El Hierro with a submarine eruptive episode that occurred in those islands?

RESPONSE. There are certain similarities with the submarines eruptive processes in the Hawaiian archipelago. Dismissing emissions associated with submarine lavas of the Loihi seamount and the submerged part of the lava field-kupaianaha PuuOo system, on the southeast coast of the island of Hawaii, volcanic system that remains active today, but which characteristics have nothing to do with what happens in El Hierro, it is true that submarine eruptions have been reported with some similarity in some islands such as Necker island in 1955 (at the western end of the Hawaiian archipelago).

In this case the process took place in a volcano located about 80 km east of Necker Island under a depth of more than 3000 m. In this case the vapor column reported more than 1000 m above the ocean surface. In 1956 was reported between the islands of Kauai and Oahu (island where Honolulu, the state capital, is located), intense bubbling, turbulent motions in the sea water, significant changes in color and strong smell of sulphurous gases, similar as is observed in El Hierro.

At the Hawaiian volcanic episode, neither columns of steam or mixture of gases and ash came to develop. Those episodes of submarine volcanism were perceived as being punctual and of very short duration.


4 - There is much speculation about the volume of magma available in El Hierro, from your point of view, what would be the most effective method that can be used for calculation? Could you be encourage to make an approximation?

One way to estimate the volume of magma available, not ejected, is the effect caused by that magma accumulation on the surface deformation of the ground, from the depth of magma injection and configuration, namely whether it is horizontal or vertical and, in the latter case, its orientation if it can be determined. There are estimates of the order of 100 million to 1 billion cubic meters of magma accumulated beneath the surface of the ocean floor. When asked if I would dare to make an approximation, I can answer that this estimate seems reasonable. Also of note is that maybe, in the end, the eruption ejects out something of the order of just one hundredth of the volume of magma.


5 - Both the earthquake last Friday's 4.3 º and 4.6 º as of today have been felt in other islands, including Tenerife. Felt in Tenerife and La Gomera is in the middle. It may be a silly question but I can not understand why people feel the 2 islands are completely isolated volcanic edifices by the ocean (not in the same plate, where it is normal). Seismographs okay, but people? This would suggest that the magma chamber may be broader than one thinks and can spread more or deeper waves?

Judging by what the National Geographic Institute shows us, the earthquake of 4.6 º felt in Tenerife, was also recorded dramatically both in La Gomera and La Palma. Now, what one feels is dependent on the people who decide to sit down and notify or shut up; on the other hand, feeling the seismic vibrations of low magnitude earthquakes is something too subjective. Two individuals in the same place may feel differently from the passage of seismic waves. You can tell others do not tell anything at all and this I can say by pure experience. The earthquake of May 9, 1989, where many people left in terror to the streets, I felt absolutely nothing from it. From a small tremor felt on the island of Faial (Azores) in the decade of 80, others who were with me did not feel anything. It is also true that according to the nature of the soil, an earthquake can be amplified in areas with softer soil or sand, can be amplified and be felt with great intensity while in rocky terrain and compact nature may be overlooked.

As for the propagation of seismic waves, they do so through the rocks below the ocean floor so they can reach any of the islands. The farther the island, the lesser the shock wave, but although the islands are separate buildings, they all share the same substrate: the oceanic crust and much of its journey it made through the cortex before entering the rock formations of each island.


6 - Do you know how deep underwater the Restinga volcano is already at? Do you think we can see it coming out above the surface?

It is known that the eruptive mouth is about 200 meters deep, on a cone of about one hundred meters high and 500 diameter at the base. We also know that landslides from the submarine escarpment areas near the volcano have occurred in large blocks. This means that the volcano can be built and destroyed as part of the progresses of the eruptive process. There is still much magma volume to be delivered so we can see a new island, and if the magma continues to come out the process would eventually bring forth this island above the ocean surface and probably would be accompanied by the emergence of hydromagmatic events with high risk of explosion .
But for that, the eruption source must get much closer to the surface, a situation which today does not seem to be the case.


7 - Today what's the probablity that an eruption would likely occur on land in El Hierro?

To give a number in terms of percentage in my opinion is meaningless, and its utility is essentially to meet the insistent demand of political authority on duty who always asks for a location which specific diagnostics can not give them. In my opinion, that the eruptive process started in underwater conditions, can lead to an eruption on land (subaerial eruption), as it is possible that the volcanic system extends below the island from north to south.

I remember before the eruption, there were figures of probability that it took place. Figures are given as a 20% chance that the eruption took place. Well because with this 20%, although the eruption took place in an underwater environment. I personally have a 20% chance of having a car accident or plane crash, or simply because I get on a car or a plane I get on course.

If you force me much and make me give you a number, which I instinctively shun, I would say that between 1% to 5%. Rather low probability, based on the concentration of seismic sources which are not located on land. We also say that this number can vary depending on time and as a consequence of the situation at a particular time even though we speak of an estimate of future short-medium term in all cases.


8-A few days ago I was surprised to see you in a television interview where [the journalist] asserted there is a relationship between the full moon and eruptions and earthquakes. So I set out to ask them [El Hierro] to prove their claim. I waited till November 10, and found that El Hierro did not say anything to support his opinion.
However, and according to the chart I sent him, they have not confirmed his statement regarding full moons.

Enclosed is the graph with the earthquakes which have included the full moon, so you see, have nothing to do one thing with another.

Do not you think that this picture you could have done before releasing to the media his theory?

Greetings. Carlos Soler

see: https://mail.google.com/mail/?ui=2&i...f_guzb8qwa0&zw (Link not operational)



RESPONSE:
Not necessarily because I have not released to the media any theory nor do I have the honor of being the father of any theory in this regard. But regardless of what the reporters asked, I remember that I referred only to volcanic eruptions and seismic activity.

That said, as I said in the interview, the influence of the phases of the moon on eruptive phases have been attempted to be proven by other researchers in environments such as the Kilauea volcano and I simply state this idea, which is not much less crazy, at the request of a situation that is not trivial, is the fact that many people may not have a scientific culture but treasure popular wisdom, not to disparage, said that with the full moon, eruptive event happened in El Hierro of greater intensity than occurred up to that point. I asked about that and obviously, you understand the only sensible thing you can say is that the tidal influence is exerted not only on the mass of ocean water but also on solid ground and the bodies of magma in the subsoil and that this can be an influential factor to consider about the volcanic activity and that is as undeniable as undeniable is the existence of tides caused by the moon and the sun, unless we have missed something and someone will discover a new cause for the origin of the tides, why not?. For new discoveries is never too late and minds must be kept open but without the sprawl.

The idea of ​​the relationship volcanoes moon emerged from Steve and Donna O'Meara's marriage, two volcanoes hunters in the style of now deceased Maurice and Katia Krafft who thought about the existence of such correlation. Subsequently, studies carried out by staff of Hawaii Volcano Observatory revealed that the lunar influence on the eruptive phases was reduced by about 1% or whatever it is: of 3900 tidal maximum since the first half of the nineteenth century, 3850 had no connection with eruptive phenomena. This is like saying that such a correlation does not exist in general terms either, without denying the relationship, that the tidal influence may be one among many others triggers an eruptive episode.

Perhaps the circumstances of the interview, the speed of it and the subsequent assembly have been able to convey it otherwise. But if it helps to clarify this answer, I will tell you and all readers that there is no evidence to support such a correlation and I feel that my words seem to have suggested otherwise.

But to finish, it does not preclude the claim that the tidal forces, if not on Earth, are the cause of intense volcanic activity on other planetary bodies in the Solar System. I am referring to Io, the first satellite of giant Jupiter in a 2:1 orbital resonance with neighboring Europa, which, together with the giant Jupiter, is causing periodic tidal deformations which can generate Io's most active volcanic systems around the known Solar System.

What do I conclude from this? Well, while on Earth in general, and on El Hierro in particular, tidal force as the cause of volcanic phenomena and eruptive phases manifests itself as little more than negligible, on other planetary bodies subjected to more intense tidal forces, this factor configured as essential in the development of active volcanic systems, BUT IN THIS CASE, CORRELATION BETWEEN ERUPTIVE PHASES AND PHASES OF MAXIMUM OR MINIMUM TIDAL DEFORMATION IS ALSO NOT KNOWN.

Thank you very much everyone.

Jose Antonio Rodriguez-Losada

[Hervé]

The stain of the volcano of La Restinga days ago. INVOLCAN

The critics integrates Pevolca

El Hierro: The crisis was not only sismovolcanic. Tremors have also been among scientists

CIRA MOROTE MEDINA:
Special Plan of Civil Protection and Emergency Response for Volcanic Risk, the famous Pevolca, which manages the geological crisis of El Hierro, has invited a group of researchers from the two Canarian universities and other scientific organizations to come to the island for a meeting. This gesture, which has been practiced in the past, now has a special character, because the guest list contains some names which, so far, were excluded from the discussion and decision-making bodies. Those involved do not say a peep, but peacetime seems to be coming.

This change in the wind coincides with leaked complains to senior officers of the CSIC for a certain opacity in the transmission of data on the eruptive process to the rest of the scientific community, according to El Pais.

Although some of these guests have stayed away to find that their experience was not required by the Pevolca, some, most notably Juan Carlos Carracedo, has been very strong and has been arguing that the management of the crisis has been the "international laughing stock". It was priceless to see him taking notes, sitting among the residents of La Restinga, in a Pevolca talk about the volcanic process.

At the front of the Scientific Committee have been María José Blanco and Carmen Lopez of IGN, who have been saved of criticism from Carracedo for their "impeccable" interpretation of seismic data, and Ramon Ortiz, Joan Martí, CSIC, have also left their mark on the island but seem to have passed into the background, unfortunately for journalists, who gave Ortiz headline after headline.

Another open front is the composition of the eruptive material. Rhyolite, basalt, trachyte, perlite ... The truth is that the issue has become a matter for fourth millennium and has caused opened fighting among some of the protagonists. The tensions are obvious, but always denied, though, by all parties.

The crux of the issue perhaps lies in the fact that professionals who have spent years studying and publishing papers on the volcanic activity in El Hierro have been ignored by those responsible for managing the crisis, when their vision may have contributed to, at least, elements of discussion. This veto has been denied by María José Blanco and Juan Manuel Santana, Director General of Security and Emergency, who have told this newspaper that anyone who has applied for scientific [inclusion?], within the framework of the Plan, has been welcomed.

As for universities, the fact is that the rules governing the Pevolca is to have both schools as members, but has not been the case in practice. That led to the creation of a committee, both outsiders, which was attended by representatives of the ULPGC and La Laguna, but had no real room for maneuver. The University of Gran Canaria, in the words of Vice Chancellor for Research, Fernando Real, says that this new approach "is very positive and will help improve on the best scientific coordination of the eruptive process." Will the tremor ceased?

***************************
Interesting comments to LaProvincia.es above article...

My favorite summarizing Pevolca state of affairs:

Pevolca should dump Google in their efforts to search about volcanological phenomena

[Hervé]

No signs of Ramon Margalef since it entered the GPS dead-zone on the 16th:

Said dead-zone is defined south-west of the solid yellow (non-dotted) line from S&R aircaft flight above El Hierro:

... so, that's the sector in which Margalef has been operating around for the last 3 days (and nights)... including a 2-hours standstill above Polly's coned-head (see post # 1576).

[Hervé]

From Earthquake-report.com:

Update 18/11 – 19:56 UTC

- Following the locally well informed El Hierro Digital we might see a far better image from the Las Restinga Telefonica webcams than we have had so far. The current 2 webcams will soon be replaced by High Definition webcams. Reader Ian Carson reported earlier today that the new webcam was being installed on a far better and stable mast than the one before. Ian took a couple of pictures which he shares with you.

- The Cabildo and Telefonica will also install 2 new webcams (probably the onces they are taking away at La Restinga) in the El Golfo area. Spoiled Childs as we are, we will start asking from now on for an infrared webcam at the Las Calmas sea.

Gracias to the Cabildo President (Mr. Alpidio Armas) and Telefonica on behalf of the earthquake-report.com readers.



Webcam installation in La Restinga - image courtesy and copyright Ian Carson - Click on the image to increase the size

[Hervé]

Strongest so far (3.3 at 18:27):

For the day:

Frequencies spectrogram, the vertical streaks indicate “events” (tremors/EQs) whereas the horizontal ones reflect volcanic/magmatic activity:

From Wikipedia: A Harmonic tremor is a sustained release of seismic and/or infrasonic energy typically associated with the underground movement of magma and/or venting of volcanic gases from magma. Being a long-duration continuous signal from a temporally extended source, a volcanic tremor contrasts distinctly with transient sources of seismic radiation, such as tremors that are typically associated with earthquake and explosion.

How it's looking like now from Las Puntas de La Frontera:

Refresh your browser to get the latest traces


For the last 10 days, following the count of EQs as shown by the orange bars (≥ 2.0), it now shows whatever Polly is up to as far as seismic activity is concerned:

New cumulative graph starting October 10, 2011. The continuously changing scales keeps compressing the earlier graphs to the bottom and to the left!

Location of the EQs for the last 10 days:

[CENTER]

Refresh your browser page to get the latest numbers and positions.

[Hervé]

A little excercise I did in modifying the original IGN EQ spatial plot of 2011/11/18 of 22:58 GMT:

in matching horizontal and vertical scales:

... gives a totally different picture to work with: the gap between the two main areas of tremor swarms is being closed meaning that the two magma chambers are getting connected and that the main magma feeder is located under the El golfo area.

Also, there isn't much of a mushrooming happening but rather a straight, narrow plutonic emplacement.

[Hervé]

Bizarre... not one EQ tremor logged on the IGN list since a 1.6 at 22:16 yesterday.

Not even the 22:58 one which might mean it was Mag. < 1.5...

I don't know what Polly is cooking but she is either using a steam pressure-cooker or it's a low heat stew...

Ooops... a 1.9 at 02:51... that's better knowing it's a stew.

[randles]

Good Morning Avalon

Just back from the UK visiting my Grandson...
I managed to take some video whilst flying over the South East Coast of El Hierro, Pollys stain is hugging the coastline..

Source: https://youtube.com/watch?v=A5snAURcm-w

[sygh]

Great footage, randles. Hope you had a wonderful trip seeing the kids, and the grandson.

[sygh]

Thanks, Zo, for superimposing all the seizmic data. I kept trying to picture it in my mind. It does look like a horizonal flow, it's always looked like a horizonal flow, not of El Hierro but right under El Hierro. What a culster of seizmic activity to the north!!! One after another in the same place. There must be some venting up there as well. What's your take?

[Hervé]

Posted by sygh (here)
Thanks, Zo, for superimposing all the seizmic data. I kept trying to picture it in my mind. It does look like a horizonal flow, it's always looked like a horizonal flow, not of El Hierro but right under El Hierro. What a culster of seizmic activity to the north!!! One after another in the same place. There must be some venting up there as well. What's your take?

Hi sygh!

From the tremor plot of all the seismic events on El Hierro, it seems that the magma emplacement follows the, roughly, N-S system of fissures of the area (see post # 1569) which, on the island itself, is capped by all the volcanic material since the birth of the island.

Hence, the EQs, as indicators of magma pressure, delineate the progress of said magma/fluids/gases: vertical along the fissures then lateral due to some cap encountered on the way up but always along the main system of fissures.

Since Ramon Margalef has been working in the N-W sector of the El Golfo area (I suspect) for 3 days+nights and just resurfaced from the GPS dead-zone... I suspect there is something happening around the active hydrothermal areas:

Also, the harmonic tremors are back to full motion... with little activity noticed in the La Restinga area... so... something's up in El Golfo!

[sygh]

Just read your reply. Yup. It most certainly seems likely. And the Island of El Hierro will stand. Continued meditations and best wishes.

[Daughter of Time]

Well Amzer Zo, you certainly do your homework. You don't just speak words, you give proof! And i'm no a scientist so it's not as if I understand the graphs but it's all very impressive. Thank you for all the information.

[Hervé]

From Volcano discovery and their on-site obesrvations:

El Hierro volcano (Canary Islands, Spain): increase in tremor and signs of a possible new submarine vent near La Restinga

Saturday Nov 19, 2011 20:21 PM | Age: 6 hrs



The new area of upwelling water, located ca. 300 m offshore (19 Nov)

During our observations from near the south coast at La Restinga yesterday, we could not observe any activity at the surface of the water. This corresponded well with a sharp decrease in tremor measured by the Instituto Geográfico Nacional (IGN).

Today, we could see areas of the ocean surface flattened by likely upwelling water rising from below, at a much closer distance to the shore than the previously active vent area, at only about 300 m distance from shore and slightly to the east as compared to the former area. Volcanic tremor has increased significantly again.


Zoom onto this area with flattened circular areas of the sea surface clearly visible (19 Nov)

We suspect that a new vent might be forming or has formed in this area. Whether this leads to another "jacuzzi" or boiling water area is only speculation at this point. The situation remains interesting.

*******************
So, it seems that Polly is burping closer to the shore now... unless it's a new quirk of local currents being offshoot disturbances due to invigorated acitivity at the main vent?