El Hierro

[jand]

HT are picking up again.

http://www.02.ign.es/ign/head/volcaSenalesDiasAnterioresHora.do?nombreFichero=CHIE_2012-02-10_10-11&estacion=CHIE&Anio=2012&Mes=02&Dia=10&tipo=2&hora=10-11

[jand]

The boat is back looking at the stain.

Reply


dfmorvan says:

 February 10, 2012 at 11:26


And again they made a detour. I wonder what they are looking for ?

[jand]

earthquake-report.

Update 10/02 – 11:12 UTC
 - Harmonic tremor keeps increasing in the past hours to low-medium levels.
 - The depth of the 10/02/2011 04:45 earthquake was corrected to 11 km. and magnitude lowered to 1.1
 - We believe the Ramón Margalef scientific Vessel might be in the process of acquiring images of the submarine volcano as this morning has spent long periods of time above the vents with not much movement.

Update 10/02 – 08:41 UTC
 - 2 new earthquakes since midnight UTC/ Especially the shallower earthquake is attracting our attention (if confirmed by IGN). These shallower earthquakes (2 shallow earthquakes yesterday were recalculated to depths of 10 km or more) are very unusual in the El Hierro earthquakes and remember that exactly a couple of shallower earthquakes triggered the start of the eruption in October, this after many weeks of earthquakes. We experienced a similar situation yesterday with 2 earthquakes respectively at a depth of 3 and 6 km. Today's new 3 km depth earthquake must certainly alarming IGN scientists (if true). - People tend to diminish the strength of the eruption based on what they are seeing in the Las Calmas see, but an eruption is far more than that alone. Lava balloons are not necessarily signs of a shallower depth of the vent as they have been  seen at the Azores islands while a submarine eruption took place at several hundred meters of depth.
 10/02/2012    01:56     Depth 12 km        M 1.5     SW EL PINAR
 10/02/2012    04:55     Depth 3  km        M 1.2     SW EL PINAR
 - Harmonic tremor is very regular, but is increasing bit by bit since yesterday morning.
 - Our conclusion : this eruption is not over yet and may carry surprises.

--------------------------------------------------------------------------------

Update 09/02 – 20:41 UTC

[jand]

What means the "depth" of an earthquake ?
 Don, an ER reader just commented as he did not know exactly what we meant with "depth" of the earthquakes. As Don, will certainly not be the only one having this question, we do try to give a simplified answer to his question. We can write 5 pages on this subject bit if we limit it to the essentials, it is mainly the following :
 An earthquake has always a breaking point or cracking point. In scientific terms it is called a Focal Depth or  Hypocenter. The epicenter is the location on the surface or otherwise said on a flat map. The focal depth is together with the epicenter the most important parameter of an earthquake.
 For tectonic earthquakes, the shallower the depth the more dangerous it is. The deeper, the less chance you will feel it. Compare it with an explosion of huge quantities of dynamite. If it explodes 10 km below your house at night, you will almost be ejected out of your bed, if at 500 km you will sleep through it.
 For volcanoes the focal depth is important for the location of an eventual vent, outburst. Below a volcano is a complex system of cracks, lava tubes etc. Below 5 km there is no problem. Even 5 km is a huge distance for magma to reach the surface. But if the focal depth is less than 1 km, i can guarantee you that the hairs of the IGN scientists at El Hierro are rising and  that adrenaline will stream through their blood.
 To make it easy, we use "Depth" instead of Focal depth or hypocenter.

[jand]

earthquake-report.com

Update 10/02 – 23:57 UTC
 - An 7th earthquake occurred at 22:49 UTC at a preliminary depth of 8 km here.
 - An 8th earthquake with a magnitude of 2.1 occurred at 23:51 UTC at a preliminary depth of 9 km here.


Pevolca meeting - Image courtesy Diario El Hierro

Important Update 10/02 – 22:57 UTC
 - Quiet a surprise today to hear a lot of mixed news reports (or at least confusing messages) from Pevolca, the safety committee managing the possible danger of the eruption. Pevolca is a committee existing out of scientists, authorities, emergency teams, police etc.
 Pevolca has given their estimate of the situation with interviews to the local and national press.
 - Pevolca sees a decrease of the volcanic activity (as Mr. Ortiz stated earlier this week)
 - La Restinga touristic boats are allowed to have aquatic activities at least 4 NM (nautical miles) from the volcano and may navigate max. 450 meter (0.25 NM) along the coast. !
 - Pevolca (commenting out of Madrid) has stressed that measures can be changed immediately if conditions would alter and press them to do so.
 - the current alert levels and NO-NAVIGATE area remains like it is (except the larger 450 m area along the coast).  Until now boats were allowed to enter and exit the La Restinga port close to the coast.
 - The RED alert (vent area) and YELLOW alert (island) are maintained.
 - El Hierro will receive 5 million euro to gradually normalize conditions of life
 - Alpidio Armas is talking with a number of companies to revitalize the El Hierro touristic sector
 - UME (emergency division) has been allowed to withdrawn from El Hierro and started their withdrawal on February 3.
 + well, here we have 2 new earthquakes, which brings today's total to 6
 10/02/2012 21:43 Depth 10 km  M 1.8   SW FRONTERA
 10/02/2012 22:49  Depth 8  km  M 1.0   SW EL PINAR
Earthquake-report.com opinion :  As distant observers from all over the world, a lot of people will have a hard time to understand what is happening here. With an HT still present, occasional strong jacuzzi and with continuing earthquakes going on (some of the most powerful since new year happened last week), we can understand that the treat for the island is manageable, but diminishing the Pevolca report is at least a bit confusing.

[jand]

Avcan FB Page Copied and translated posted earlier today.


A las 8:32 a.m., sin previo aviso, un terremoto de magnitud 5,1 en la escala de Richter, con epicentro justo debajo de la ladera norte de la montaña, fue el responsable del derrumbamiento de parte de la montaña, aproximadamente unos 7-20 segundos tras su inicio.........


A total of 10,000 earthquakes were recorded before the great eruption of May 18, the majority concentrated in a small area of 2.6 km, just below the gap of the north face. All visible eruptions ceased on 16 may, which reduced the interest of the public and the number of spectators in the area. But, however, on May 17, public pressure forced the officers in charge, to allow the issuing of a small group of people inside the danger zone. Another tour was scheduled for 10 a.m. of the following day. Being Sunday, was averted more than 300 loggers were working in the area. It is estimated that just before the eruption, the volcano had received approximately 0.11 km3 of magma, whose pressure forced the displacement of 150 m from the section of the north face of the mountain, and heated the entire system of groundwater of the volcano, causing steam explosions.

Sequence of events that took place on 18 May.
 Volcanologist of USGS David a. Johnston, after spending all night Saturday in his observation post about 10 km north of the mountain, may 18 at 7: 00 a.m., transmitted by radio the last data of the measurements taken by laser. According to these data, the activity of Mount St. Helens did not show any change from the pattern that was followed during the last month. Readings about the rate of movement of the crack, emissions of gaseous sulphur dioxide and surface temperature not revealed any changes that could indicate a catastrophic eruption.

At 8: 32 a.m., without prior notice, an earthquake of magnitude 5.1 on the Richter scale, with its epicenter just below the northern slopes of the mountain, was responsible for the collapse of part of the mountain, approximately 7-20 seconds after its launch... (Translated by Bing)

[jand]

Seeing and hearing pressure in a volcano.

http://www.youtube.com/watch?feature=player_embedded&v=Ej9jdJ-913Y

[jand]

Stunning video of Tansganasoga.

http://www.youtube.com/watch?v=RXBmh-qND_8&feature=player_embedded

[jand]

Volcana Cafe Copied

Someone has plotted all the earthquakes.

Ok, just a first try

this is the density plotting of All the earthquakes since the beginning versus lat and long.

I will try later to refine the system and produce more graphs.
 Done with Octave

http://4.bp.blogspot.com/-qggPyAlJGZ0/TzeXXX3hFMI/AAAAAAAAAqc/v9PJWaB7gxY/s1600/Density%2Ball%2Bdata%2B1%2B0_001-0_001%2B2012-02-12.png

http://3.bp.blogspot.com/-QrcBjr3Fuqc/TzeXX70G8EI/AAAAAAAAAqo/g_WTT_Nzz1Y/s1600/Density%2Ball%2Bdata%2B0_001-0_001%2B2012-02-12.png

[jand]

Mizar says:

 February 12, 2012 at 10:44


It looks like the most active area now is right over this obstacle (an old vent?) only 5.4 meters deep?

http://www.flickr.com/photos/77257295@N00/6857749755/

Reply


KarenZ says:

 February 12, 2012 at 11:20


Can't say for sure due to the camera angles; but it looks closer to shore than is comfortable.

Reply

[jand]

Tansganasoga from google earth.

KarenZ says:

 February 12, 2012 at 12:44


Or as seen from Google Earth 27.73N, 18.06W

http://oi40.tinypic.com/2ppgdcl.jpg

[jand]

http://212.170.244.196/

Lots of swirling and white foam? on the webcam at the moment.

[jand]

http://www.youtube.com/watch?v=ooZrjr29tOw&feature=player_embedded

Tansganosoga google earth video.

[jand]

1126133 12/02/2012 00:16:54 27.7275 -18.0277 10.6 1.5 mbLg SW FRONTERA.IHI
 1126134 12/02/2012 00:18:19 27.7346 -18.0270 9.5 1.3 mbLg SW FRONTERA.IHI
 1126136 12/02/2012 01:01:01 27.7450 -18.0291 8.0 1.1 mbLg SW FRONTERA.IHI
 1126137 12/02/2012 02:48:18 27.7464 -17.9894 9.8 0.7 mbLg SE FRONTERA.IH
 1126139 12/02/2012 03:12:48 27.6478 -18.0452 1.4 mbLg SW EL PINAR.IHI

1126145 12/02/2012 07:35:31 27.7594 -18.0297 2.7 0.8 mbLg W FRONTERA.IHI
 2 hours ago · Like · 1

Reply



1126147

12/02/2012 11:28:27 27.6785 -18.0666 10 2.0 4 SW EL PINAR.IHI

People have felt the 2.00 earthquake some comments from Avcan FB copied below.


I already reporté in 11: 28 which also appears in the IGN 2.0 in El Pinar. About ten minutes ago I felt again vibration on Windows as the 11: 28 because we'll see that they say on it.


This 11: 28 I think have felt vibration in the front door of House (wood), casually walked down the top. There is no wind.
 See Translation


Avcan FB Page Copied

A las 10:48, movimiento leve, pero con sonido fuerte y sordo, como una explosión lejana, que nos tapó los oídos. La misma sensación que cuando buceas y sientes el cambio de presión en los oídos. En Los Mocanes, Frontera
 Reportado al IGN, con copia.

#8206;10: 48, Slight movement, but with sound strong and dull, as a distant explosion, which covered us the ears. The same feeling that when you buceas and feel the change of pressure in the ears. In Los Mocanes, border Reportado to IGN, with copy

[jand]

Avcan .

The position of the last 8 earthquakes.

http://www.avcan.org/mapas/AVCAN2687.jpg?d=1329055128

[jand]

Avcan FB Copied


Buenas tardes, sobre todo a los Herreños.
 La alineación de los sismos de hoy del Golfo ( N/#8203;S ) parece que nos indica el camino del Tanganasoga.......no?, aunque sean posibles asentamientos tectónico....que ....no se


Good afternoon, especially to the Islanders.
 The alignment of the earthquakes of today's Gulf (N/S) seems to indicating us the path of the Tanganasoga... no?, although possible tectonic settlements.... that... .no is (Translated by Bing)

24 minutes ago · Like · 1.


Rayco González Lo que está sucediendo es algo realmente asombroso y desconcertante a la vez. La información de Julia Sisi y Victor Manuel dan a entender que esta situación lejos de terminar tiene todas las señales de fase de reactivación.


What is happening is something really amazing and disconcerting at the same time. Julia Sisi and Victor Manuel information give to understand that this situation far from finished has all signs of reactivation phase. (Translated by Bing)

9 minutes ago · Like · 3.


Conchita Rojano Taberner ¿Pueden ser posibles asentamientos los sismos de la cumbre? Lo dig porque ya están a 8- 10 km... y a menos de 10 podrí significar una "prealerta"


Can possible settlements be of the Summit earthquakes? The dig because they are already 8 - 10 km... and to less than 10 could mean an "early warning" (Translated by Bing)

8 minutes ago · Like

Avcan Reply.

Good afternoon. The earthquakes of settlement are not safe. Cause or may cause crack and "open" microfracturación. (Elena)
36 seconds ago · Like

[jand]

Update 12/02 – 13:09 UTC
 - Just like yesterday, a powerful jacuzzi is presently stirring the Las Calmas sea
 - HT had increased bit by bit and is presently at low medium levels
 - 1 new earthquake : 12/02/2012    11:28     Depth 10 km     M 2.0     SW EL PINAR

[jand]

Avcan FB Copied and Translated.

Good morning. I am concerned that simo in the terrestrial coastal North. Depth around 3 (before revision hipotetica), then we will see. do that is going to be corrected as many "shallow" earthquakes, there are devices that are malfunctioning?.? In recent days, and in that same area there have been a couple of them that originally were on the 3 km and then correct them. not is it high time tune devices or systems of measurement?. The security of the islanders is at stake. I was that by the account that brings them they will not distort the data, but it should be more tuned when what is not alarm the population. With regard to the EMU, they know what they do and I don't want to make more comments. Many times I get a mental idea that the bag of magma under the island of el Hierro is larger than the island building and I say that because earthquakes occur scattered but please all sides, North, South, East, West and in fairly remote areas of North and South marine areas, maybe this bag from magma split few Kim to the South of the island of La Palma and quite Miss South of the Iron. Needless to say that this big bag of magma would be quite in-depth, pk but turns off and vamonos. In short, we are still waiting to see that you can spend with these earthquakes to the North, allegedly not so shallow....

[jand]

On Avcan someone has commented the tremor has doubledshown on the graph below.

http://www.ign.es/ign/head/volcaSenalesAnterioresDia.do?nombreFichero=CHIE_2012-02-12&estacion=CHIE&Anio=2012&Mes=02&Dia=12

[jand]

AvcanFB Copied.

Hi Mary Carmen. Liquefaction processes are complex. Needed materials that have capacity to contain water between its pores or discontinuities, needed a seismic process causing a vibration suitable entry into resonance of materials capable of causing liquefaction. The size of the grain of the material licuefactarse, is very important. Each grain size, might say, you need a "intensity" in the vibration generating processes of expulsion of the trapped water. Estimated materials type gravel, it would take more than 7 magnitudes to cause liquefaction. IE. Para_que occurs this process are necessary: a) a soil composed of a susceptibe material contain water, b) water filling the pores, c) an earthquake with a magnitude of adequate to provoke the phenomenon, according to the diameter of the grains. As you can see it is not a simple process. Usually associated with earthquakes of magnitude greater than 6/6, 5. There are volcanic regions in which limited liquefaction processes can be seen affecting channels, levels of ash... and that seem to be related precursor earthquakes of some importance of eruptions Plinian and subplinianas (explosive) I leave you a link where you can see pictures of footprints of liquefaction in the Campo de Calatrava, Tenerife and Italy. http://www.uclm.es/profesorado/egcardenas/SISM.htm hope you have clarified something. (Elena).

[jand]

Avcan FB.

Good evenings. Although Member of AVCAN here and now the only thing I will give is my personal opinion. It is true that the decision taken can cause and causes malaise, dissatisfaction and other feelings. But let us think and remember news that recently we have seen and read where the scientific community are not even able to agree on the situation that is now the eruption: some say we're in one third phase, others that it is stable, and there are even to ensure that it is in its final phase. If any of us had to make a decision based on disparate conclusions, who can ensure that the decision taken was correct? Absolutely no one. Is the decision taken by the PEVOLCA correct? Each can have their own opinion, but know anyone can know it, even if it is a mistake, because the data which are made known scientists themselves are conflicting each other. That could have been reduced in part EMU device would have been at all? Is it could have done, as was he could have maintained during a short period of time while you get more data. Hopefully the decision is ultimately correct, all I can say is that it is not easy to take a decision on the basis of such contradiction in scientific reports. And I hope that it is taken solely on the basis of these data and there are no other factors which have also influenced when taking this decision. (Nino López Alonso)

[jand]

Just posted on Avcan FB by Tomas Perdino



Incremento de sismicidad superficial, tremor activo, etc..hasta que no esté extinto cómo se puede hablar de estabilidad!!. ¿qué indica una evolución estable del fenómeno?, ¿tenemos un patrón predecible?. A mi entender se está subestimando al mayor episodio volcánico acontecido en la historia moderna de Canarias, exceptuando Timanfaya!

Shallow seismicity, active tremor, etc. increase.until that is not extinct, how can we talk about stability!. What indicates a stable development of the phenomenon?, do we have a predictable pattern?. In my opinion is is underestimating the largest volcanic episode happened in the modern history of the Canary Islands, with the exception of Timanfaya! (Translated by Bing)

[jand]

earthquake-report.com

Update 12/02 – 19:13 UTC
 - Very strange jacuzzi today. The camera is still on the same mast, but the normal location of the jacuzzi is no longer the same. We seem to have multiple gas emission points this afternoon. Lets hope that Joke will have taken some pictures of the different locations.
 - HT decreasing again after having had a strong period (see below)

[jand]

This video was taken at 1902 showing the activity and perhaps two vents?

http://www.youtube.com/watch?feature=player_embedded&v=VcbV0NgFelY

[jand]

Update 12/02 – 23:50 UTC
 - Today we have seen a present jacuzzi through the whole day, even at early morning hours as captured in the webcam. Here is a time lapse from Julio del Castillo Vivero from 04:30 till 20:05 UTC showing a strong jacuzzi with also currents moving the stain. Speeds have been adjusted at different times of the day.

http://www.youtube.com/watch?v=od035vIhoP8&feature=player_embedded

[jand]

Avcan FB Copied and translated.

http://www.avcan.org/sismica/graficas/G807.jpg?t=1329081227

In the graph of evolution from the depths of earthquakes in what you carry year, lately those parts are more populated of earthquakes, and not only that, are also more concentrated in a specific area, area which incidentally seems is migrating to more shallow areas, seems not only it that there are more earthquakes in less depth.


Specifying a bit, this is the summary of what you have in this third stage, which is what can be seen of activity is concentrated. and if you continue towards more Meseta levels as these last few days, will have to be outstanding. At the moment is about 8 - 11 km. (Henry).
See Translation

[jand]

Note AVCAN 448 - earthquake activity - VOLCANIC - island of iron - 13 February 2012-10: 30 pm peninsula - earthquake and volcanic activity continued moderate, with activity the mar de las Calmas and a deep earthquake yesterday in the area of punta Arenas Blancas. Also looks pretty microsismicidad detected but not located in the spectrogram. Signal of volcanic tremor continues in the eruptive zone of la Restinga, yesterday repunto again, and today remains, albeit with a small tendency to decrease. New 6 earthquakes. Magnitude between 2.0 and 1.1. Depths between 10.1 and 11.6km (and one to 8.8 and another at 23.2km). 5. The day before yesterday. Yesterday 10. Today will be 2. In total van 12196 earthquakes located in El Hierro by IGN from 9: 00 a.m. of the day 19 July 2011 (Henry).

[jand]

Volcano cafe copied.

Carlos says:

 February 13, 2012 at 15:41


PUBLIC COMPLAINT...
 IGN manipulation continues.

In their report of today (for yesterday) they say:
 "10 earthquakes were located in the Julan and Sea of calms, of magnitudes between 0.7 and 2.0
 on the Richter scale, with depths less than 23 km."

what is the meaning of less than 23 km? haha
 Yes... yesterday there were EQ´s at 3km, 8km, 9 km,10km...

If you are not manipulating and giving information with valium the right sentence is:

"with depths between 3 and 23km"

I´m afraid when I see this kind of "treatment of the info".
 I know we all are not going to die... Then I dont understand ther stupid of these manipulations...

I am not going to let pass any manipulation nor IGN, nor PEVOLCA...
 Although tomorrow is Valentine's day and my love for Carmen Lopez is of public domain.

Today´s awesome pics of our intrepid reporter joke volta.
 Than you very much Joke. https://plus.google.com/photos/110327184570944806725/albums/5708611300130095041?banner=pwa&gpsrc=pwrd1#photos/110327184570944806725/albums/5708611300130095041

[jand]

volcano cafe copied.

GeoLurking says:

 February 13, 2012 at 07:16


First of all, I'm not a geologist and have no training what so ever in the field.

However, I do study it as a hobby in an effort to understand what is going on... and to be more able to throw the bullpoo flag when I see someone spewing number two. Generally, I do this with a plot and ask the proponent of the idea to show me. It just really depends. I've been invited off of more than one loon site due to my pragmatic approach. More recently, I just plot stuff.

In the ongoing quest to hone my bullpoo detector, I have learned a few things. Some of it is applicable to this post. So.. here is some additional info.

The magnitude of an earthquake is almost never in the same scale from one geological organization to another.

Looking at

http://www.gps.caltech.edu/uploads/File/People/kanamori/HKtect83b.pdf

you can see some of the different scaling systems that are used. That paper is an effort to gain some insight about how to move from one system to another.

Why the different system? Well, that has a lot to do with what is being looked at. Some quakes are small, some are large, some deep, some shallow. Seismic gear has gone through many generations of technology, and today's instruments are much more sensitive than older gear. How do you use the new information and have it mesh well with historical quake data?

You make adjustments in your scales. That, plus the wide variety of gear only makes the problem worse. To us, the general public, we don't care if the scale is ML, mblg, Mw, etc... all we care about is the number. But that scale is important. It relates back to the amount of energy that the quake releases. (Note, Iceland uses ML, 'local magnitude' as well as another one that I can't identify... it's just called "M" in the list along with "ML"; IGN uses both mglb and ML in the flat file.)

Big quakes.. ones that you see reported from larger events are almost always in Mw... this is the moment magnitude. It came about from Kanamori as a way of unifying some of these scales.

Smaller quakes don't have enough information in the seismo (cuz they are small) so they have to take up another way to measure them... in El Hierro's case, you will see mblg. If I read it right, this is determined from the coda.. or the length of the actual trace on the seismo. (I could be wrong though)

First Motions can tell you a lot about what actually happened at the quake location... and allow the geophysicists to make some determinations about how everything happened.

An earthquake (techtonic) will radiate energy away from the quake... this energy is seen on the seismos a the wave front passes by. By looking at the very leading movement of the trace, it can be determined if the seismo is in a compressive area, or an area of dilation (extension). Typically there will be two of each. Doing the complicated math behind these first motions at a large number of stations allow the researchers to determine what the focal mechanism for the quake was. This focal mechanism (with enough stations) can tell what the angle of the fault plane is, what the dip angle is etc.

Take a look at any large quake's "beach ball" and the data behind it... that is what they are looking at.

Here is a link to the beach balls for the Japan Mag 9.0 from last year.

http://earthquake.usgs.gov/earthquakes/eqinthenews/2011/usc0001xgp/#scitech

Now... there are other things that can be done with these first motions. A while back... 1996 I think, there was a quake in Iceland at Bardabunga that did not have a 'double couple' solution. What the initial waveforms pointed at was that there was no stike-slip, and that there was no volume change. (displacement). Magmatic quakes have a very specific waveform that does not match the strike-slip of tectonic quakes.

http://www.iris.edu/hq/gallery/photo/8066

Best they could figure (based on what I have read) is that either magma moved up along the sided, and the crust moved down to fill the void, or that magma moved up and the crust moved down on the sides. Wild stuff... all determined from the nuances of the waves on the seismos.

[jand]

earthquake-report.com

Update 13/02 – 17:08 UTC
 Patrick Allard, a French volcanologist was invited by French Radio Network France Inter to tell the French audience about the El Hierro volcano.  He and Jesús Gomez Gonzalo an IGN director were invited in Mathieu Vidard's  "La tête au carré", a scientific radio program. Click here for the "Audio broadcast" (French). Thank you ER reader Jean-Patrick for telling us.
 - HT is at "surviving" value right now.

Update 13/02 – 13:37 UTC
 - 3 more earthquakes since the latest update
 13/02/2012    08:51      Depth 6 km        M 0.8      W FRONTERA
 13/02/2012    10:16      Depth 16 km        M 0.9      SW FRONTERA
 13/02/2012    12:52      Depth 11 km        M 0.6      W EL PINAR
 - Joke Volta February 13 morning images. The seagull image is dedicated to Pam, who follows the birds in relation to the eruption like a dedicated scientist!