Tirelessly updating Avalon on the El Hierro eruption.

[TWINCANS]

Posted by Amzer Zo (here)

Posted by TWINCANS (here)
In post 1550, there was a sentence I don't understand;

"In the vertical component there is still a phenomenon of deflation in the south of the island."

I wondered if anyone could explain?

Hi Twincans!

See post # 1120 and post # 1294 for background data on this.

The idea is that the magma chamber underneath El Hierro is displacing the ground on El Hierro. That ground displacement, recorded through GPS stations, is analyzed along three components: two horizontal and one vertical.

A deflation indicates a negative displacement (sinking) and is assumed to be due to magma erupting whereas a positive displacement (inflating, rising ground) is correlated to fresh magma injections (refill of the chamber).

Hope this clarifies it?

PS: All displacements are measured in millimeters.

Thanks for clearing that up. I thought it mean sinking but as it's only millimeters there's no need to hems the trousers higher!

[Hervé]

Speaking of which, Geolurking has two new 3D rendering videos, one from GPS data, the other from seismic data for the month of November up to the 15th:

Source: https://youtube.com/watch?v=wULIibExLgM

Source: https://youtube.com/watch?v=eQGvGoBeEL4

[Hervé]

Rich idea some people might want to follow...

http://www.flickr.com/photos/controt...n/photostream/

[Hervé]

State of the jacuzzi area from yesterday:

[GlassSteagallfan]

Thanks to all of you who keep this thread updated. Nice pictures too.

[Hervé]

Strongest so far (3.2 at 05:09):

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 a definite increase in seismic activity:

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]

Now, how about that smoking gun in the El Golfo area...

Here it is as published by IEO (http://www.ieo.es/apartar/ieoprensa/hierro/261011.pdf):

What's that mean?

Simply that some hydrothermal activity is taking place in the El Golfo area.

That could be as spectacular as the "Old Faithful" or a mere inconvenience for pedestrians as in Iceland:

See this page for explanations: http://www.jonfr.com/volcano/?p=1788

[Hervé]

Beautiful digital survey and rendering from the Ramon Margalef crew (http://www.ieo.es/apartar/ieoprensa/hierro/261011.pdf):

However, the above sea bottom lanscape has already suffered some changes with a landslide and the build-up of a second volcanic cone (see post # 1556)

In any case, now we know what we are looking at when watching the Restinga webcams (http://www.hierroendirecto.movistar.es/) and how far away is Polly bubbling.

[Hervé]

... deeply troubled here...

... thanks to the high quality of the PDF put out by IEO, I started looking at their El Golfo survey... nice looking... so on...

Then, old training and habits quicked in: these look awfully straight...


Let's zoom in!

Yep! Nice rift/graben structures there! No wonder El Hierro skidded all the way down!

Then...

What's that there?

Let's zoom in a bit more...

@&%$! Pheu*&$#g $*!t! No wonder they got hydrothermals there!

Can you see that?



Let's zoom in more:

See them now, these linear structures?

The second set of them... at 1200? Right there:

What's that mean?

Well, it means that instead of having nice fissures slicing the crust linearly, what we have is an intersection of two sets of fractures and rather than having a nice sliced omelet we got scrambled eggs... as a crust in that area.

I don't think it will take very long, now, for the magma to find its way around to there.

The only redeeming thing is the great depth of that particular area.

[Hervé]

Juan Manuel Santana, ayer, en El Hierro. i PEDRO GUERRA

'El Hierro population to be evacuated by sea and air in case of explosive eruption'


PEDRO GUERRA - SPECIAL ENVOY EL HIERRO:
Santana seems to be sure that the decisions that have been taken are appropriate, especially for what he is responsible, which is the safety of persons. Though he speaks of the eruption of the north, he confirms that there is enough reaction time.


- How would you rate the management of the seismic crisis of El Hierro?

- In general, good. Keep in mind that this is the first time the Civil Protection Plan for Volcanic Risk (Pevolca) was activated, following its adoption last year, and like everything there are always new issues to be corrected, but it is important to have had an instrument that allows us to manage everything that is the process and the risk associated with this process. Remember that Pevolca's aim is to prevent and that people are safe of a given risk.


- And that is fulfilled?

- It's hard to keep people safe against a particular risk when in addition people get accustomed to that risk as time passes, with respect to others that are imminent, such as fire or heavy rains. In this case the risk is associated with whether the eruption occurs or not, or the occurrence of earthquakes or not. When they occur and are seen, people get more nervous and assumed to be at risk, but as time goes by there is this sense of habit and that you can live with risk. With the eruption phenomenon that happens, to the extent that there is more activity, people feel there is a particular risk and, as time goes, that feeling relaxes. This is common, it goes with everything and it complicates management. It is therefore very important to give all the training and information prior to this process.


- When the Pevolca has to make a decision, how do you get to think in terms of a resident? How do you move a member of Pevolca into the skin of a resident of La Restinga, for example?

- The Pevolca has a number of internal organs that are helping make decisions. Basically, decisions are made ​​based on what scientists have to report at any time, and scientists meet priorly, go over the data and communicate the evolution of the process and associated risks that can come with this process to the director of the steering committee. Ultimately, the responsibility lies with the Government of the Canary Islands, but in other institutions are represented in Pevolca that support decisions. There has been no prior decision to come not supported by the scientific committee.


'- From the technical point of view, is the Pevolca convinced that the tunnels Roquille is prepared to support a major earthquake or open the tunnel by public demand?

- The tunnel is a basic infrastructure in El Hierro and as such, logically, this means that as time goes on you can see that the danger associated with that risk is not going not happen because people are used to nothing happening. But that does not mean it can not happen. When closed, the tunnel is not closed because of its internal conditions, but because of the slopes of the access roads to the tunnel. Why? Because we have reports from the Geological and Mining Institute of Spain (IGME), which had already made previous reports, and said that these slopes were the most susceptible to landslides. Linked to that, there are specific reports on the seismicity occuring and the risks involved. Based on this, decisions are made and what has been tried is to hone the specific risk measures we are under which are determine by the technicians. When access is banned by the outer slopes, not inside the tunnel, which is a problem that has always been attributed to the inside, for whatever reason, it has stuck well. Inside the tunnel, there are no landslides.


- Why does it open during the day and closed at night? What is the difference from the point of view of the danger?

- The decision to open for the day is derived from the variation in seismicity, the scientists tell us that large-magnitude earthquakes would occur at a depth of over twenty miles and that surveillance is more feasible during the day. At night it is more complicated.


- The Gulf. How complex is the crisis management in Frontera in case of eruption?

- Has increased complexity due to a greater population and by having more people there are more vulnerabilities with an increase of the number of people. That makes everything more complex. It is true that the expected type of eruption in the Canary Islands is a type of eruption similar to the Teneguía (La Palma), a fissure eruption and very, very local. Depending on where it occurs, it may be more dangerous or not. Not by lava flows, which are believed to represent some danger, but maybe by the ash flow. We're talking no direct hazard, but water pollution or ash accumulation would cause a collapse of any structure. It is currently expected, but everything is ready.


- In the worst case scenario in Frontera, how would an evacuation run?

- In the worst case scenario, with a type of eruption acquiring an explosive nature with great as cloud height and which is not expected now to begin with, we would have at least two days to prepare everything, with symptoms very clear on the ground as greater deformation and cracks in the ground even before the eruption occurred. There would be a series of indicators that would trigger the decisions. And if this is so, you're all prepared with the placement of temporary shelters in various locations in Valverde and in turn the possibility of evacuating people off the island to south of Tenerife. At first it would be handled through the Port of La Estaca after taking people by car, and there is enough time, otherwise we have to use an airway through the Gulf, helicopters and special vehicles. But this is something which is not contemplated at this time.


- How long does the Pevolca think it might extend this seismic crisis?

- Do not know. Scientists have begun to see signs of crystallization in the material ejected into the Sea of ​​Calm, when the more crystals there are, the closer would be the end of the eruption. But that is in the south of the island, now we face a new stage in the north and do not know if it will cause an eruption or not.


- If you get another earthquake of 4.6 or higher, is the Island is prepared to stand it?

- Scientists have warned us of the problem of landslides, also because greater magnitude earthquakes are right now associated with greater depth, they do not increase the risk with respect to what happened in previous days.


- You presided over Pevolca delegated advisor, have you perceived the so-called 'scientific war' around the El Hierro volcano?

- I have been on program committees and was able to participate a little in the debates, there is scientific debate. It is logical. We talk about people from different scientific streams who are somehow arguing about something. And the discussion is what comes to the best knowledge of the discipline. I have not seen, personally, that kind of difference. I do believe that all institutions want to do their best.


- Are discussions heated in the scientific committee?

- Not particularly. Everything is very respectful.


- There are scientific groups who have felt displaced by the volcanic crisis of El Hierro. What do you think?

- The Pevolca includes those institutions that are to form part of it. IGN is basically responsible for volcano monitoring, and other institutions that jointly conducted with IGN that advisory to the steering committee, as the CSIC, IEO, InVolCan, Canarian universities, etc.. A phenomenon of this type necessarily draws scientific attention, and that's why the Canary Islands Government has sought to facilitate the participation of all researchers, through its institutions, directed the committee to study any part of the phenomenon. Now, that must be distinguished from the scientific committee, which mission is to advise the Steering Committee Pevolca referring to measures taken for safety. They are two separate issues.


- What happened to the Cabildo de El Hierro, which seems to have been away from the Pevolca and decisions?

- I had the opportunity to see the statements made ​​by the president, Alpidio Armas and I mean they are part of the steering committee, and the same information that the scientists forward to us is what they have. In the process of decision making, all have the opportunity to ask any questions one can have to the head of the scientific committee, and decisions are made from what is discussed by the scientific committee. We can understand that an administration of local character may have more pressure, depending on where you are. In this case the council is under pressure to all residents of the island of El Hierro, but most importantly the government is the safety of people. And, based on the information that scientists give us all from time to time, decisions are made. You can not make decisions based on intuitions of the kind "is that it has never happened at all." That can not be the case and decisions are made based on risk. We want to avoid any problems of insecurity for the people, that is what guides us in making decisions.


- Do you think politics has been around the volcano?

- From the direction of Pevolca, no. We can be criticized because the measures have been thought too preventative compared to what has happened then, but then nobody knew, nobody knows what can happen. Our job is to prevent rather than cure.

[Hervé]

Rant of the day:

The most frustrating and irritating web-page in the whole world-wide web:

[Hervé]

El Hierro November 16, 2011. Picture from Laura, IGN geologist.


El Hierro has recorded 11,604 earthquakes in four months


Twenty-nine of these movements were recorded on Tuesday, five of them felt by the population

EFE:
The National Geographic Institute has registered 11 604 seismic events in El Hierro from July 17, according to data released Wednesday by the Civil Protection Plan for Volcanic Risk Islands (Pevolca).

Twenty-nine of these movements were recorded on Tuesday, five of them felt by the population, the largest of which 3.4 was located 3 kilometers off the coast of Frontera, 17 kilometers deep.

The ground deformations on Tuesday followed the same pattern of stability as in previous days in the horizontal components and the slick in the water caused by undersea volcanic eruption off La Restinga showed low activity.

[Hervé]

Ramon Margalef back to La Restinga after a rest at Los Christianos in Tenerife:

Changes of the sea bottom landscape since the first campaign:

From CalidoT at TodoGeologia.com

From Sondebueu at TodoGeologia.com

[Hervé]

Strongest so far (3.6 at 16:25):

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 a definite increase in seismic activity:

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]

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:

[Hervé]

It seems that Ramon Margalef may be having a go with the Liropus 2000 since it is keeping stationary against wind and current, steady location right over the top of Polly's head:

That's the puny paler smudge, 1/4 left of center, in the above picture

That was the steady positioning for almost two hours!

Earthquake-report.com thinks it was the Guardia Civil vessel, however there is a big difference in size and the Guardia Civil doesn't have an aft tall structure which Margalef has:

[Ria]

Thank you for your efforts, I imagine it is all very scary and at the same time very exciting.
My thoughts are, is this Atlantis rising?
Much love and keep safe.

[Hervé]

Posted by Ria (here)
Thank you for your efforts, I imagine it is all very scary and at the same time very exciting.
My thoughts are, is this Atlantis rising?
Much love and keep safe.

Hi Ria!

Let me try to deconfuse ideas and issues here:

The thing with volcanism, if ever there was anything left of Atlantis in the area, it would not only have sunk very deep but, on top of that, would have been buried under thick lava flows, layers of ashes and sediments.

Therefore, even if by some of Nature's tour-de-force the ocean floor came to the surface... well, it would be an ocean floor of thick lava flows and layers of ashes covered with sediments and no Atlantis in sight.

Accordingly, the only way there could be an Atlantis rise would be metaphorically as in that NWO retracing the foot steps of what Edgar Cayce recounted having happened in Atlantis.

That's for another thread than this one.

[Ria]

I do appreciate that would be the case and would not expect, to see any remains.
Your work is invaluable, keep safe.

[Hervé]

The City of El Pinar has installed two new webcams in La Restinga area focusing on the Jacuzzi spots with a much higher quality than those of Moviestar.

http://www.elpinardeelhierro.com/periodico/

The views from the two cameras are alternating on the same screen.