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El Hierro

Started by admin, October 12, 2011, 10:40:14 AM

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jand

#3450
December 31, 2012, 21:37:46 PM
Happy New Year Cllr Collins to you and all.

jand

#3452
December 31, 2012, 22:57:48 PM Last Edit: December 31, 2012, 23:06:18 PM by jand

jand

#3453
January 01, 2013, 10:02:33 AM
Note 182-01/01/2013 - 10: 45 h peninsular. -EVOLUTION AND TRACK ACTIVITY QUAKE-VOLCANIC IN THE ISLAND OF EL HIERRO. HAPPY new year, happy 2013 to tod@s...
earthquakes http://www.avcan.org/?m=Mapas&a=mapa&mf=5247 from 01/01/2013

- light blue (12)... at the moment. EARTHQUAKES of 31/12/2012 - red (57). EARTHQUAKES OF 30/12/2012-(0). EARTHQUAKE of 29/12/2012 - dark blue (1). EARTHQUAKE OF 28/12/2012-(0). EARTHQUAKES OF 27/12/2012-(0). EARTHQUAKES from 26/12/2012 - light green (1). EARTHQUAKES from 01/12/2011 to 25/12/2012 - yellow (38).

We said goodbye to the year with a new swarm, which possibly indicates a new process of intrusion underground, there will be to see how evolve the GPS, and currently runs 57 earthquakes located yesterday and the 12 that van today, to the North of the island next to the Roques de Salmor, West into the sea of the Gulf. Several alignments are noticeable, but perhaps can highlight a component almost n-s, but a little inclined to the NNW-SSE. I remember everyone that if feel something strange on the island, do not hesitate to fill in the questionnaire of the IGN, you can put it in the box of text at the end of the questionnaire, it is very important: (Enrique)

http://www.avcan.org/?m=Mapas&a=mapa&mf=5245

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jand

#3454
January 01, 2013, 10:31:57 AM
You can see the evolution of seismically libreradas accumulated energies, as this latest revival is seen perfectly in the release of energy begins to be important, in less than 24 h more energy than in the last two months has been released...(Enrique).

http://www.avcan.org/sismica/graficas/G2152.jpg?t=1357032458

jand

#3455
January 01, 2013, 12:47:30 PM
Latest blog from Manfred the German Man who lives on El Hierro.

Will need to be translated has maps and photos.

http://elhierro1.blogspot.de/

jand

#3456
January 01, 2013, 14:14:07 PM
2013-01-18 13:47 UTC

- The swarm has not completely ended yet and looks to be reactivating again.
- The depth layer where the activity generates stress is gradually getting less deeper with a lot of quakes in the 16 km layer (a change from the 17 to 21 km yesterday). This does not mean that there should be a higher risk now, only that the magma pressure is gradually getting higher.
- We are sure that the current earthquakes are occurring in yet another area of the island which was not yet active since the early activity. The current area is more to the north of the island (north of Las Puntas) which is creating a whole new story as we do not know how the layers will behave. Again a surprise at El Hierro!

www.earthquake-report.com

jand

#3458
January 01, 2013, 21:35:44 PM
same graph with the earthquakes represented to see the evolution of the depth of them, at the moment 96 earthquakes... (Enrique

http://www.avcan.org/sismica/graficas/G2165.jpg?t=1357075116

jand

#3459
January 02, 2013, 17:19:39 PM
IGN has spoken.

Translated.

The Director of the Observatory Geophysical Institute geographic national (IGN) in the Canaries, Carmen López, ensures that the new seismic reactivation in El Hierro, with more than 100 earthquakes since December 31, is of lower energy than the previous ones occurring in June and September of last year, and that there is no reason for the restlessness of the population, since are not given the parameters necessary to propose the Declaration of the yellow traffic light by volcanic risk.

Lopez, in statements to this newspaper, explains that as a result of this new permanent stations network seismic series GPS have been measured deformations vertical and horizontal one centimeter on the surface of the North of the island, especially in the Valley of the Gulf.

The geologist details the hundreds of earthquakes recorded since new year's Eve have been located "North border" and to the West of Valverde, almost everyone in the sea, between 15 and 20 kilometers deep, and without that there is migration of that activity to upper layers of the crust. It is, he reiterated, "very small, weak," earthquake in a series much less intense than in September, and much more with regard to the June.

Requires that the current seismic swarm "seems even he has lost strength in the last hours, with less frequent events", but stresses that IGN will continue to monitor the evolution of this phenomenon, which, in any case, "has not had enough power so that the population has felt it".

Lopez recalls that the volcanic process initiated in July of 2011 "not yet finished, and there is more calm periods and others more intensity". In fact, has not ceased having earthquakes in all this time, some days 10 and some none. In any case, insists that "the Reactivations are less intense".

On the location of the earthquakes in a part of the island where until now they had not focused, it noted that "the seismicity is being produced at different sites, because by where he began seismic 2011 series the crust is already fractured and full of hot material, but is broken not more out there".

Preguntada on if it has been able to cause new intrusion of magma, responded that this is one of the possibilities, but you can also try "from the same magma that is already under the island, and which cools" and that can still cause "overpressure" and breaking other parts of the island building.

"In this new series of seismic energy involved is very small, and very low magnitude earthquakes, there are no signs for the unrest, and we will continue to monitor", abounds responsible for observations of the IGN in the Canary Islands.

http://www.diariodeavisos.com/ign-concluye-reactivacion-sismica-en-hierro-es-mas-debil-anteriores/

jand

#3460
January 02, 2013, 17:21:57 PM
DATA GPS IGN: Everything seems to indicate that he confirms the intrusion of magma at depth associated with the seismicity of recent days: zone of the Gulf: an elevation of the terrain or inflation of about 2 cm in the last tip, least in HI-04 with something less than 1 cm in HI-02 and HI-03 note little appreciable and almost nothing in HI-05. In terms of horizontal deformation, is clearly observed a shift westward and southward, more pronounced in HI-03 and HI-04, less in the other two. FRON and HI-01 not yet updated. Valverde - La Restinga zone: in HI-00 and HI-08 there is an elevation of the terrain of 1 cm more or less. In terms of horizontal deformation is observed a shift northward and this valverde (HI-00) and towards the South and East in HI-08. HI-09 (Restinga) and HI-10 (Verodal) stations are out-of-date. All these data confirm what we are having an underground intrusion at depth and that intrusion zone is where we are having the seismicity coinciding with the area of the Roques de Salmor in Eastern Gulf in the island of El Hierro to about 16 - 21 km of prof according to the seismic. Well, that, now already is being detected is an anomaly volcanic shaped inlet of magma under the island with two parameters again as already step last month of July and August. (seismicity and deformation). Tomorrow if this follows confirmation of this behavior as well will be. Gases there is no information available.

http://www.ign.es/ign/resources/volcanologia/html/deformacionHierro.html

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jand

#3461
January 11, 2013, 06:39:10 AM



Dr. Steffi Burchardt, a senior lecturer in Structural Geology at Uppsala University in Sweden, presented a talk, "Xeno-pumice erupted offshore El Hierro, Canary Islands: A tale of stoped blocks in magma chambers?" at the LASI V workshop in Port Elizabeth, South Africa in October 2012. The article below is based on this talk and also an interview with Dr. Burchardt. Over a few weeks, I will be highlighting some of the research that was presented at the LASI V workshop. This is the second post in that series.

Following a period of intense seismic activity, on October 10th, 2011 a submarine eruption began approximately 1 kilometer off the coast of El Hierro, the youngest and westernmost island in the Canary Islands, which is a group of volcanic islands believed to have been formed through hotspot volcanism. The eruption was evident from the unusual conditions on the sea surface: the sea bubbled, like a Jacuzzi, and was stained green. The large green stain was easily observable from space. In the midst of these strange conditions, some highly unusual rocks were erupted. For several days after the sea started bubbling, strange floating rocks were observed and collected off the coast of La Restinga, the closest town to the undersea eruption. These floating stones were generally tens of centimeters in size and resembled lava bombs in shape. The outsides of these floating rocks consisted of basanite , a rock type commonly observed in the Canary Islands and other volcanic ocean islands. Basanites don't generally float. However, these basanite shells floated because their insides were filled with a white to light grey, pumice-like material. Pumice is a highly vesicular rock, which means that it is a rock full of voids or bubbles, which make the rock light enough to float on water.

While the pumice-like centers explained why the rocks floated, they also raised a multitude of questions and triggered some heated debates amongst geologists. This is because pumice is not commonly produced in the Canary Islands* or in other oceanic island hotspot environments, such as Hawaii and Iceland. The lavas erupted at oceanic island hotspots are generally mafic, low viscosity lavas such as basalts (and basanites). Viscosity is, in essence, a measure of how resistant lava is to flowing. The less viscous a lava, the more likely that lava is to flow. Therefore, low viscosity lavas such as basalts tend to flow easily and also tend to regularly release volatiles such as water and carbon dioxide. Therefore, the pressures in these lavas remain relatively low, and violent eruptions are uncommon. Pumice is most commonly produced during eruptions of felsic, highly viscous, volatile-rich lavas, which are found in environments such as island arcs, not oceanic island hotspots. The voids or bubbles in pumice represent places where volatiles have been rapidly released due to a pressure change, often during a violent eruption.

So, what was pumice-like material doing in an oceanic island eruption? A number of theories were put forward to try to explain the floating rocks that were erupted off of La Restinga. Some scientists thought the pumice-like material represented juvenile, highly silicic, highly viscous magma (such as rhyolite), which is very explosive. Other scientists proposed that the pumice-like material represented re-melted magmatic material, altered volcanic rock, or reheated hyaloclastite or zeolite from the slopes of El Hierro. Mysterious in origin, the floating stones were called "restingolites" after the nearby town of La Restinga.

After extensive analysis, a group of scientists (Troll et al., 2012) proposed an alternative hypothesis to explain the pumice-like material found in the restingolites. Based on the material's high silica content, lack of igneous trace element signatures, and high oxygen isotope values as well as the presence of remnant quartz, jasper, carbonate, and wollastonite, Troll et al. concluded that the pumice-like material in the restingolites in fact represented xenolithic material from pre-island sedimentary layers that were picked up and heated by ascending magma, which caused the layers to partially melt and bubble. Looking like pumice and originating as xenoliths, Troll et al. dubbed the restingolites "xeno-pumice".

Dr. Burchardt elaborates, "Xeno-pumice is definitely not an established term. We have coined it for the first time in the case of El Hierro eruption. The name comes from adding the preface 'xeno-', which means foreign, to 'pumice'. We used this term because the floating rocks of El Hierro present the characteristics of pumice, but they are actually not pumice in origin; they are actually xenoliths. We found out, based on mineralogy and also the fact that they contain detrital sand grains and fossils, that they are actually not magmatic in origin but rather that they are xenoliths from the sedimentary layers that underlay the Canary Islands. So, they are older than the volcanism. When the magma was rising, it stagnated at this level and interacted with the sedimentary rocks, sandstone and minor carbonate, and the magmas transported the xenoliths up with them to the ocean floor, where they were erupted. But in the process of the ascent of these xenoliths, they were subject to heat from the magma, so they started to melt. Since they contain a lot of water, this water started to boil and formed bubbles. The end product was something that looked like a pumice: lots of bubbles surrounded by a glassy matrix."

Dr. Burchardt explains, "The El Hierro eruption was a very fortuitous circumstance for our work because my colleagues and I had been working on similar rocks from volcanoes worldwide, but that they were not previously recognized as xeno-pumice. The El Hierro eruption was therefore some kind of a breakthrough for our research in this field, and there will be a whole series of papers dealing with xeno-pumice from different parts of the world."

By November, the xeno-pumice rocks were no longer being erupted, and worries that a dangerous, explosive eruption could occur at El Hierro abated. The identification of the restingolites as xeno-pumice was also good news for the hazard risk at El Hierro.

Dr. Burchardt explains, "It was good news that these xenoliths are sedimentary in origin because it means that there is no rhyolitic magma beneath the island, which means that a big explosive eruption isn't likely."

While the xeno-pumice rocks do not carry the message that an explosive eruption is likely to occur at El Hierro, they do carry other important messages from the deep. The unusual xeno-pumice rocks observed erupting at El Hierro in 2011 can provide much direct information about the interaction of magma and oceanic sediments and also may indicate that recycling of oceanic sediments into magma is an important process at ocean islands. Further study of xeno-pumice from the Canary Islands—and also from other parts of the world—will go a long way towards helping geologists better understand how volcanic eruptions at ocean islands interact with oceanic crust and sediments as they make their way to the surface.



*Update: Commentor Siim Sepp points out that intermediate composition pumice is found on the Canary Islands, most notably on the island of Tenerife. This is a very good point. I have perhaps oversimplified the explanation– pumice can be found at volcanic ocean islands under certain conditions. Thanks for pointing this out, Siim!

The full blog with photos and maps can be seen at :

http://blogs.agu.org/georneys/2013/01/09/lasi-v-xeno-pumice-mysterious-floating-rocks-of-the-canary-islands/

jand

#3462
January 13, 2013, 09:18:24 AM Last Edit: January 13, 2013, 09:23:33 AM by jand
Note 185-12/01/2013 - 16: 00 h peninsular (18: 00 h kuwait). -EVOLUTION AND TRACK ACTIVITY QUAKE-VOLCANIC IN THE ISLAND OF EL HIERRO. Greetings to all from my new site, Kuwait, Spanish market did not allow for more and had to go out of my country... that if I am still reminded of tod@s you. Today looking at looking at, there is something that strikes me, the deformation in all sensors is again on the rise (the ground again lifted), after the intrusion of the turn of the year we have where I lift fast, had several more tranquil days and even seems that you referring is desincha (part of this effect seems weather, since also decreases the Palma and Tenerife), and now instead that trend to swell, seems to start to pick up, and not only in the vertical, also in the horizontal.

http://www.ign.es/ign/resources/volcanologia/html/deformacionHierro

.html http://www.seis.nagoya-u.ac.jp/sagiya/Sagiyas_Page/Canary.html

It is true that if the vertical and horizontal deformation continues to increase, we could have a new seismic swarm in the island of El Hierro in the coming days, hours can... but there is still time habra that followed its evolution from it, at the moment a sismito from 2.1 yesterday South of the lighthouse of Orchilla and soon. http://www.avcan.org/?m=Mapas&a=mapa&mf=5294 earthquakes from 01/11/2013-(0). EARTHQUAKES of 01/11/2013 - blue sky (1). EARTHQUAKES of 02/01/2013 to 01/10/2013 - light green (6). EARTHQUAKES from 30/12/2011 to 02/01/2013 - yellow (124). The map shows perfectly the earthquakes of the swarm of the change of year (yellow) and the small earthquakes of dissipation of efforts, more small and shallow (green). Blue yesterday no entraria in nondiscrimination category, seems due to the deep system which gave the Sanjuanero swarm of last year and that occasionally moves. I remember everyone that if feel something strange on the island, do not hesitate to fill in the questionnaire of the IGN, you can put it in the box of text at the end of the questionnaire, it is very important:

http://www.avcan.org/?m=Mapas&a=mapa&mf=5294

http://www.ign.es/ign/resources/volcanologia/html/deformacionHierro.html

www.facebook.com  AVCAN

jand

#3463
January 20, 2013, 20:31:42 PM
2013-01-20 14:35 UTC
- ER readers Sissel and Leona and some other people yesterday (see below) have alerted us concerning a thicker HT line on the CHIE graph. As there was not an increase in volcanic earthquakes, we indicated that the thicker line was instrumental or weather related.
Diario El Hierro created a lot of rumor this morning mentioning a football field size stain in the Las Calmas Sea.
Still no other activity which is needed to have a volcanic process (multiple earthquakes, deformation, gases etc).
In a second article a little later Diario indicated that the stain is a 30 to 45 days returning phenomenon, only this time the stain is bigger than normal.
Politicians on the island have requested at IGN to explain what is happening. In the past IGN commented that the stains are the result of a continuous degassing process on the new volcano crater area.
We remember also seeing video fragments from a ROV showing this degassing.
In other words, no renewed eruption process at the moment

www.earthquake-report.com

jand

#3464
January 20, 2013, 20:34:23 PM
DIARIOELHIERRO.ES, writing (20/1/2013 16: 33 hours)
The national geographical Institute (IGN) has confirmed on Sunday that the spot green color that has appeared in the area of the Mar de Las Calmas, is due to a punctual degassing of the eruptive process, according to sources consulted by DIARIO EL HIERRO.

Likewise, IGN has stated there are no seismic events located in the area where it has appeared today this new spot.

This morning, the inhabitants of La Restinga stood with a new spot opposite their homes, specifically to two kilometers from the town and in the same area where the underwater eruption of the Mar de Las Calmas occurred. He was a vigilante fishing who alerted 1-1-2 on the 10: 45 hours from this Sunday, as he said newspaper EL HIERRO.

1-1-2 Sources consulted by this newspaper confirmed the appearance of this stain and claimed that this phenomenon is usually repeated every month or month and a half, product, according to IGN, of a punctual degassing of the eruptive process.




jand

#3466
January 20, 2013, 20:39:30 PM

Dos sismitos localizados a las 17,32 UTC:
1186655 20/01/2013 17:32:20 27.7481 -18.0332 9 1.0 4 W FRONTERA.IHI
  • info
    1186654 20/01/2013 17:32:57 27.7428 -18.0259 10 1.6 4 SW FRONTERA.IHI
  • info

    about an hour ago · Like · 5..

    Luis Francisco López Peña Dos más completan el grupito de eventos que se veía en CTIG, hasta que ha desaparecido la franja horaria de 17 a 18 UTC:
    1186656 20/01/2013 17:34:55 27.7465 -18.0390 11 0.7 4 W FRONTERA.IHI
  • info
    1186657 20/01/2013 17:36:00 27.7266 -18.0294 12 0.9 4 SW FRONTERA.IHI
  • info

jand

#3467
January 20, 2013, 21:23:49 PM
Los cuatro sismos que nos trae Luis, son en tierra:
2 casi en el mismo lugar, en las laderas del Tanganasoga sobre Los Llanillos, otro subiendo la carretera de la Cumbre por encima de Tigaday, y el último en la zona de la Cruz de los Reyes

Four
earthquakes that Luis, brings us are on Earth: 2 almost in the same place, on the slopes of the Tanganasoga on the see, another up the road from the Summit above Tigaday, and the latter in the area of la Cruz de los Reyes

www.facebook.com  AVCAN

jand

#3468
January 21, 2013, 18:49:04 PM
Lots of comments on the Avcan Facebook page regarding the green stain showing yesterday it has been said that it maybe something to do with plankton from Africa this has just been posted on the Avcan page.

yo vi ayer burbujas de gases salir a la superficie, y no solamente yo, mucha jente en la restinga las vio, y no venian de Africa....

yesterday I saw bubbles of gases exit to the surface, and not only I, much people in la restinga saw them, and came not from Africa

jand

#3469
January 27, 2013, 20:52:56 PM
EVOLUTION AND TRACK ACTIVITY QUAKE-VOLCANIC IN THE ISLAND OF EL HIERRO. Today was not going to put part, only had a sismito deep in the western part of the island of last minute yesterday... that could indicate the input again magma under the island, but until a while ago, not much... 1187313 26/01/2013 21: 38: 50 27.7371 - 18.1898 34.9 km 1.6 W border.IHI - iron and for awhile, two localized Wiggles, although they are more like a succession that appear as multiple lines in the spectrogram, are the typical crack-crack - crack of breakage of rocks or what is the same thing, has all the earmarks of a pressurization in course in the center of the island, although it is still soon, if we continue down this pathWe will not take in having more seismicity and above 2.3 in the same area, since they have been on the same site as the swarm of yesterday that reached a maximum of 1.9, pinch more n If cabe and today have risen to 2.3 and the depth is maintained between 10 and 11 km. 1187394 27/01/2013 16: 57: 51 27.7251 - 18.0181 10.6 km 1.5 SW border.IHI iron 1187393 27/01/2013 16: 48: 19 27.7287 - 18.0148 11.0 km 2.3 SW border.IHI El Hierro in the updated map is what I commented, good night to pass. http://www.avcan.org/?m=Mapas&a=mapa&mf=5312 earthquakes of 27/01/2013 - violet (2) earthquakes of 26/01/2013 - pink (5) earthquakes of 25/01/2013 - green (4) earthquakes of 24/01/2013 - red (1) earthquakes of 23/01/2013-(0) earthquakes of 22/01/2013-(0) earthquakes of 21/01/2013-(0) 20/01/2013 - blue sky earthquakes (5) earthquakes of 10/01/2013-19/01/2013 - yellow (11) reminder to everyone that if you feel something strange on the island, as this tremor, or vibrations do not hesitate to fill in the questionnaire of the IGN, you can put it in the box of text at the end of the questionnaire, it is very important


http://www.avcan.org/?m=Mapas&a=mapa&mf=5312

jand

#3471
January 29, 2013, 10:00:19 AM Last Edit: January 29, 2013, 10:20:30 AM by jand
 1187529  29/01/2013 05:07:35 27.7232 -18.0116 11.9 1.3 NW EL PINAR.IHI El Hierro

1187528  29/01/2013 05:05:00 27.7309 -18.0174 11.2 0.9 SW FRONTERA.IHI El Hierro

1187525   29/01/2013 04:46:26 27.7249 -18.0084 14.9 0.8 NW EL PINAR.IHI El Hierro


IHI El Hierro the three sismitos in the same area these days Ridge, there have been a few more detected sismitos but not locate, but nothing important for now.

http://www.avcan.org/varios/Imagenes/20130129madr.jpg

jand

#3473
January 31, 2013, 18:01:29 PM Last Edit: January 31, 2013, 18:05:40 PM by jand
1188033  31/01/2013  16:27:15  27.6383  -18.0414  15  -1  2.9  4  SW EL PINAR.IHI

http://www.emsc-csem.org/#2

jand

#3474
January 31, 2013, 18:29:16 PM

como habia comentado Enrique en post anteriores algo parece creer que algo vuelve a entrar y este sismo que ya anunciaba a ha sucedido y ahora a esperar como se comporta .

as he had told Henry in previous post something seems to believe that something re-enters and this earthquake that already announced to happened and now to wait how it behaves

10 minutes ago via mobile · Like..


Gary Cabrera Pues en Las Toscas también se sintio.

Therefore in Las Toscas also be felt.

jand

#3475
January 31, 2013, 19:20:46 PM
Just posted by Joke Volta on the Avcan Facebook Page:

I have to give reason to fernando and others, who say that it has been an earthquake this afternoon in iron probably more magnitude than indicated by the IGN.Only see that bestial sign in Chie, only to see the comparison with previous earthquakes seen from the CHIE, only to see, comparison of the signal of this earthquake and earlier, makes very little credible, which has been a "solo" Quake 2, 9... is that we... a three and a good pico... This would be more successful...And if you let us look to those signals from other stations on the island, I'm almost certain that he would be confirmed, that it was one earthquake greater than three... minimum...The people in the Gulf feel an earthquake at the other end of the island, by logic, that must have been somewhat higher to 2, 9... expected re-valoran it

jand

#3478
January 31, 2013, 19:43:57 PM
2013-01-31 19:03 UTC
- A strong (for El Hierro at least) earthquake occurred at 16:27 UTC at a depth of 15 km.
No other earthquakes have been listed by IGN today, but if we watch the HT graph, we see some real changes happening.  We are of course curious what the next hours will happen. The HT line is seriously thicker than this morning and the amplitude increased a little before the strong earthquake. Location of the epicenter here. The epicenter of this quake (more or less at the new volcano buildup) makes this episode even more interesting.
CHIE graph as showed on the screenshot below can be followed in real time here (30 minutes delay)
Let us stay alerted in this phase and please comment whenever a serious change is noticed

www.earthquake-report.com
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