El Hierro

[jand]

Instituto Geográfico Nacional (IGN) reported that during 11-17 July both seismic activity and deformation at El Hierro decreased. There were 87 seismic events located, most of them offshore SW of El Hierro Island at about 20 km depth. Only six earthquakes were M 2.7 or higher, and the maximum magnitude recorded was 3.4, corresponding to two events: 14 July at 1952 and 17 July at 0746. The deformation rate decreased, with maximum values of less than 1 cm in the horizontal components.

Geologic Summary. The triangular island of Hierro is the SW-most and least studied of the Canary Islands. The massive Hierro shield volcano is truncated by a large NW-facing escarpment formed as a result of gravitational collapse of El Golfo volcano about 130,000 years ago. The steep-sided 1500-m-high scarp towers above a low lava platform bordering 12-km-wide El Golfo Bay, and three other large submarine landslide deposits occur to the SW and SE. Three prominent rifts oriented NW, NE, and south at 120 degree angles form prominent topographic ridges. The subaerial portion of the volcano consists of flat-lying Quaternary basaltic and trachybasaltic lava flows and tuffs capped by numerous young cinder cones and lava flows. Holocene cones and flows are found both on the outer flanks and in the El Golfo depression. Hierro contains the greatest concentration of young vents in the Canary Islands. Uncertainty surrounds the report of an historical eruption in 1793.

http://www.volcano.si.edu/reports/usgs/#hierro

[jand]

Update 25/07 – 08:37 UTC
- The last earthquake of July 24 was recalculated as a M2.9 earthquake at a depth of 21 km. This quake was felt by the people of the island as a very weak shaking (MMI II).
- The 1 km depth earthquake is still in the IGN charts, which means that it was confirmed. We do not see however any shallow eruptive action at that location (El Golfo bay) as there were almost no other earthquakes in that area. The probable cause is the deformation stress.
- The first earthquake of today was a M1.8 quake at a depth of 18 km below the western part of the island
- Vertical deformations are up again at PINA and FRON stations

www.earthquake-report.com

[jand]

Update 25/07 – 15:39 UTC
- The island is wobbling again + a lot of shallow earthquakes (some were recalculated from yesterday). In order to give a good overview of the earthquakes from yesterday and today, we have recapitulated all these earthquakes. The least we can say is that what is happening is very curious. The epicenter of most of the earthquakes is still in the line of the lighthouse but the depths are peculiar. Are all these quakes from stress related deformations or is there more to tell ?. Scientists have the clues in their hands, but as far as we know have not yet communicated about it.
The 3 first shallow earthquakes occurred in a matter of only 2 minutes.
The recalculation of these quakes is making the El Golfo shallow quake with the coloring of the water less credible as all the shallow epicenters are below the island (close to the Orchilla or lighthouse)

25/07/2012     08:59:53     Depth 20 km           M 1.8     mbLg     W EL PINAR
25/07/2012     08:39:40     Depth 21 km           M 1.7     mbLg     W FRONTERA
25/07/2012     06:16:38     Depth 24 km           M 1.6     mbLg     SW FRONTERA
25/07/2012     06:04:20     Depth 18 km           M 1.8     mbLg     W FRONTERA
25/07/2012     05:46:43     Depth 3 km           M 1.7     mbLg     SW FRONTERA
24/07/2012     21:17:49     Depth 21 km         M 2.9     mbLg     SW EL PINAR
24/07/2012     20:13:21     Depth 2 km           M 1.9     mbLg     SW FRONTERA
24/07/2012     20:12:09     Depth 2 km           M 2.1     mbLg     SW FRONTERA
24/07/2012     20:11:38     Depth 2 km           M 1.7     mbLg     SW FRONTERA
24/07/2012     12:19:43     Depth 21 km           M 1.9     mbLg     SW FRONTERA
24/07/2012     10:23:13     Depth 18 km           M 1.7     mbLg     W EL PINAR

Update 25/07 – 14:04 UTC
ER reader Mafl commented below this article that a German language El Hierro blogsite has spotted some coloring of the coastal waters in the El Golfo bay. The coloring was noticed after the 1 km depth earthquake with epicenter in the El Golfo Bay. The writer says that he only reports what he saw and that science have to find out whether what was seen has a volcanic background or not.
Image courtesy ElHierro1.blogspot.de

The photo can be seen on www.earthquake-report.com

[jand]

Posted on the Avcan Facebook Page this morning.

Translated.

Two teleseismos captured today by MACI on Tenerife station. It is interesting to hear how it resonates the planet as a campaign. Much has accelerated to make audible frequencies below 4 Hz so that one day you hear in a few seconds.


Teleseísmos en MACI

[jand]

Update 26/07 – 10:59 UTC
- 2 earthquakes so far today.  Both hypocenters were at unusual depths (13 km for the M1.8 earthquake and 16 km for the M1.6 earthquake). Both epicenters were located in the old vent area in the Las Calmas sea.  Another "to follow" evolution.
- The University of Nagoya's deformation stats are showing a strong climb in Ultra Rapid vertical deformation at SABI (more than 1 cm).  The other stations are stabilized.
- We do not know whether we are the only ones having trouble in reaching some data from the IGN website.
- The Atlantic Explorer (chartered by the ULPGC or in long words the University of Las Palmas de Gran Canaria) is back in town and is doing some research in the Las Calmas sea (also in the Lighthouse area).

www.earthquake-report.com

[jand]

Update 27/07 – 15:18 UTC
- The first earthquake occurred at 14:12 UTC. It measured a depth of 20 km and a Magnitude of 2.1
- Vertical deformation of station SABI dropped again to the levels of the day before yesterday. On the other hand PINA shows a 1.5 cm climb today, a very strong deformation if the Ultra Rapid data are confirmed later on.
- Reader Roland reports that the Captain of the Atlantic Explorer, currently cruising the Las Calmas sea made a statement that magnetism values are very high, probably due the presence of a lot of iron the the moving magma below the sea bed.
- Image of the submarine volcano in La restinga captured by the probe of the Atlantic Explorer on July 27 during the campaign of the ULPGC – QSTAR Guayota.

The image can be seen on www.earthquake-report.com

[jand]

Update 29/07 – 09:05 UTC
- No earthquakes so far today
- Deformations seem to be stabilized
- Reader Roland writes in the comment section that further cone depth analysis may result in only 84 meters instead of the 88 meters which was reported before. These 4 meters are important if a new earthquake crisis with eruption activity in the old vent would strike. The ULPGC will examine the Atlantic Explorer data early this week. Some are writing that the lesser depth have occurred the last couple of weeks (since the last Atlantic Explorer mission). Some are skeptical as there was no visible action in the Las Calmas sea and as no HT was noticed on the seismograms.

[jand]

Raymond Ortiz has posted very interesting information about the situation in El Hierro and as far as I understand he points out there are two seperate systems of activity.

The article will need to be translated as it is in Spanish.


http://www.volcanesdecanarias.com/index.php?option=com_content&view=article&id=243%3Aentrevista-especial-hierro-ramon-ortiz&catid=118&Itemid=122&lang=es

[jand]

Another interesting article on El Hierro this time by Joan Marti who it is said is one one of the worlds best experts in Volcanic geology.

The article is well worth reading but will need to be translated .

He does state that at the moment that no one should lower their guard as to what is happening.


http://www.volcanesdecanarias.com/index.php?option=com_content&view=article&id=242%3Aentrevista-especial-hierro-joan-marti&catid=118&Itemid=122&lang=es

[jand]

AvcanFacebook page have reported  there has been a meeting of Pevolca at 13:00 today but still no official statement.

..Volcanoes of Canary Islands VOLCANIC island of HIERRO, update 30 07 2012 13.00 h today took place a meeting of the PEVOLCA to assess the situation of El Hierro. We are waiting to meet their conclusions..

https://www.facebook.com/pages/Actualidad-Volc%C3%A1nica-de-Canarias-AVCAN/163883668446

[jand]

Update 31/07 – 07:15 UTC
- A  M2.7 earthquake at a depth of 20 km at 03:23 earlier today. Epicenter : western tip of the island.
- NO change in vertical deformations today

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

Update 30/07 – 22:34 UTC
- A rather strong earthquake tonight. Magnitude : M2.8, Depth : 20 km, Time of occurrence : 20:40 UTC;

www.earthquake-report.com

[jand]

La información contenida es de libre divulgación debiendo citarse la fuente volcanesdecanarias.com,,
,,The information contained is free disclosure and must cite the source volcanesdecanarias.com,,

Carmen Lopez is the Director of the geophysical Observatory of the National Geographic Institute (IGN). Among other tasks it is responsible for coordinating all the human team of volcanic monitoring deployed in El Hierro. His face we have been familiar since it has been one of the scientific coordinators of the PEVOLCA that was commissioned to clarify the technical details of the eruptive activity of the iron during the month of October 2011. The volcanology passionate recognizes and ensures that if a rash is not live you never learn. With patience and simplicity that characterizes responds once again to all our questions.
1. Last June 24 there was a surge of activity with numerous earthquakes senses. To date, what is the situation of the island of El Hierro?
Since a few days ago, the seismicity has declined considerably and distortions have stabilized. In fact, the accumulated seismic energy curve shows a pattern of stability since about day 17 of July, as you can see in the attached figure (energia_hierro_10. jpg). In addition, the seismicity is located now in a dispersed manner, in the area where before was concentrated from the beginning of the recovery the past June 24.
2. What can be the source of this process? Do they believe that remain in place the right conditions for that continue new injections of magma? It is a new process or would have related to the underwater eruption from October 2011?
So far, all the institutions involved in the PEVOLCA have worked in the emergency phase, its monitoring of the activity that is recorded in real time and valuing and interpreting changes in the system, essential for the correct interpretation of the phenomenon, the prognosis and the alert.Know with certainty the origin of this process requires a research work we have to do with all the data that have been recorded during all these months and an integrated interpretation. In any case, none of the experts we
3. Do you consider that the current crisis is part of a global process and that it has not yet finished? Or, on the contrary, consider that each process that occurs is independent of the previous one? If you respond to a cycle, they believe that it may take as the eruption of Timanfaya?In the same terms as the previous question, there is nothing ruled out, what we value for now is the evolution in the short term. Behavior in the medium term depends on the origin of the process and the mechanism (amount of available magma and situation of the local and regional efforts field both the crust and the upper mantle), little known with the studies available so far, but we hope that investigations be carried out in the near future, will improve this aspect.
4 – In recent days it seems that activity has relaxed a bit, do you think the rebound that took place from the 24th of June could return to register again in the short term?
We can not rule out any possible change in behavior. We have to wait the stabilization we're apparently looking well as seismicity and deformation, to confirm, and to do so we will have to wait a reasonable time on the order of months.
5. If they returned to produce these rises could lead to rash or would require other precursors?
It should be assessed according to the precursors are observing. Not all the eruptions are preceded by the observation of all the precursors. And we often give situations of observation of clear pre-eruptivos precursors (even several) that does not culminate in eruption
.6. Some opinions indicate that this activity may be associated with a process of resettlement what's the connection?
Again, the source of the activity. All these points are involved in a clear understanding of the process and it is recommended to have scientific evidence to be certain of what he says.
7. In June seem to combine earthquakes large with many earthquakes of low magnitude is strung forming bandeados in seismograms, it can tell us why is this alternation?
This alternation is not but a swarm of seismic activity, which is not only in volcanoes but tectonic areas that exhibit this behavior in series. Ex: the series of the earthquake of Lorca in the 1978 or which occurs after the earthquake of Lugo in 1997.

[jand]

Taking into account the characteristics of the activity recorded at these time and on the basis of the knowledge that we have today on the volcanic phenomenon is it feasible to make a forecast of developments in the situation?Forecasts of developments are carried out within the scope of the Scientific Committee of the PEVOLCA, since we are in a situation of activation of the Plan, and of course that can and should make predictions, always within the Committee, assessing the uncertainties associated with these and knowing that only they can apply with certain probability in a temporary windowIt is always determined by the evolution of the activity in real time and that usually not more than a few days
.9. A few weeks ago of warned the population of the possibility to feel earthquakes of greater magnitude is this forecast remains? What can you say in this respect?This notice is based on the statistical study of seismic catalog; If the seismic series continues to act similarly to the precedent, the seismic frequency will mark the expected maximum magnitude. This does not mean that it will produce this maximum earthquake (it is not deterministic), only that it is expected. In addition, volcanoes, the State of efforts is not uniform in such studies must be taken with caution and only as additional information.
10 And on the possible areas in which a new eruption could occur, we have heard that it is more likely that is underwater, do you share?
When the seismicity is located in the sea, 20 km from depth, and the El Hierro island has more than subaerial underwater extension, it is reasonable to think that the probability of an underwater eruption is greater.
11. The people of El Pinar assure us perceive earthquakes in a more intense way to what the magnitudes indicate and that they even perceive water vibrations similar to those observed during the hours before the eruption in La Restinga, however was discarded there are episodes of tremor. Could it explain the causes of these perceptions?The harmonic tremor that was associated with the eruption of October 2011 has characteristics very different signals to be registron in June and July. With regard to the perception by the population, should be considered the different amplifier response of soil (which has been very important in the case of some areas of the island) and the perception of swarm them seismicity (earthquakes consecutive and overlapping in time) as a continuous vibration.
12 Is the margin forecast of a hypothetical eruption still 24 hours for El Hierro?
I don't know where you can get this information. I repeat that the forecasts are valid for the time in which it is established and a specific time window. Outside of this period they are meaningless.
13. Some experts have explained it Shuffles a percentage of 30% of eruption on Earth, what scenarios are shuffled to El Hierro?
This information belongs to an assessment of the scope of the Scientific Committee and made sense to the situation at the time. In subsequent meetings will be assessed according to the current activity.
14. To date, is one of these scenarios more likely than others?We will have to wait for an updated assessment of the Committee.
15. This episode has surprised by the speed in the increase of detected activity, especially in the deformation... you can reveal this the volume of magma available?It can model (have done this) type of intrusion and estimate the shape, volume and location of the anomaly of pressure that gives rise to these deformations, although the methods are only approximate longer than the validity of the results depend on the understanding of the environment.
16. If we assume that the volume of magma is high, could this amount of magma stay there down without more or, depending on your volume, temperature, density, etc. end to find out?This magma could be where is, and would be cooling down, and therefore starting to crystallize different minerals. For a time, which depends on the characteristics of magma and its amount, it would still be able to rise to surface, until it became a moment that could only leave if you have a new injection of magma 'hot'. During these processes, changes in the State of efforts could promote the start of an eruption. The magma would finally cool to be a solid rock
When determining deformations with a GPS network, it is very important to differentiate its origin. It can be local (eg: volcanic process), regional (meteorological phenomenon, derived from sub-placa), as well as problems associated to global phenomena as well as the constellation of satellites (Ephemerides) (magnetic storms mainly). In the case of the days 3,4 and 5 July, the observed phenomenon was common deformations on El Hierro, La Palma and Tenerife result of disturbances of the ionosphere by magnetic storms

[jand]

18. Would you like to make any recommendations to the population or to the institutions?Recommendations to the population carried out the PEVOLCA. I am not who to recommend to the institutions, but I would like to than all the scientists understand the desirability of respecting this competition
19 How is that a process with a release of seismic energy as extraordinary stops suddenly as it seems you have done it possible?In the scientific literature, there are many similar cases, that having even marked a migration of earthquakes to the surface, abort without culminate in eruption.
20. How long estimate how prudential to assert that the current Unrest has ended?This issue will be dealt with by the Scientific Committee of the PEVOLCA.ABOUT VOLCANISM IN THE CANARY ISLANDS
21 Aside to El Hierro, how is the activity in the rest of the Islands?In his habitual activity more energy seismicity is concentrated between Tenerife and Gran Canaria.
22 Do we may be in a global process that may lead to new injections of magma, giving rise to a cycle in the Reactivations can happen at different points of the Canary Islands as already happened in Tenerife in 2004-2005 and recently in El Hierro?.I believe that this very interesting question will be reason of scientific studies in years to come.
23. How can global tectonics (Atlantico-africa - Europe), influencing the regional tectonic (Canaria), which in certain circumstances could give rise to a new revival? , Does or believes that current Volcanism is more determined by a local phenomenon?Local tectonics is always influenced by the regional tectonics, and volcanism both influence. What is no longer as simple is to quantify the contribution of local and regional for a particular process.
24 - A magma chamber should be hosted on the vertical of the volcanic cone? Or can be external and have its output across systems failures that facilitate the output of material to surface at a point away?Not always the magma chamber is situated in the vertical of the volcanic edifice. The journey of a magma depends on the balance between its lifting capacity and characteristics of the material that surrounds it, in particular its efforts system. Thus, the magma will follow the path that requires the lowest energy possible, and that road does not have to be vertical.SPECIFIC TO THE IGN
25. In Tenerife in recent weeks there have been earthquakes in the vicinity of El Teide but do not appear deep despite being within the network what is?The localization process depends on many factors, including the number of stations that recorded the event and the clarity of the arrival of the different phases. If these two factors are not good, to achieve the convergence of the algorithm of calculation you might need force depth for a localization solution. This is common in small earthquakes with few associated phases.
26 - Some classmates ask us we will consultemos that since last July 11, seen in EOSO an anomalous signal that seen her spectrogram seem a kind of harmonic tremor of a low frequency, around 0.4 Hz which in some kind of of volcanism may indicate movement or variations in a magma chamber not far from the areaThis signal is also noted in other seasons, and had its peak the day 14,15 and 16 July, being most weak today but it still remains.Does not seem that there is anything significant apart from ocean noise, telesismos and anthropogenic noise. I can not answer you to the last question, since I don't see anything abnormal. Are you sure that the date and station is correct?

[jand]

This is the latest blog from Raymond Matabosch it will need to be translated as it is in French on Avcan FB he has commented that the latest earthquake at 14 km deep is on the edge of the El Julan Cliffs

http://www.66270rosesetepines.com/article-mercredi-01-aout-2012-a-11-h-30-complete-darkness-108718095.html

[jand]

A very interesting article which has been Translated.

,,RUBÉN DARÍO GARCÍA LEÓN (EFE) | Santa Cruz de Tenerife

The stones that came to the surface as a result of the crisis earthquake volcanic last year affected the island of El Hierro are the most radioactive in the world, he told EfE the physicist Antonio Darwish, Professor in the Department of soil science and geology of the University of La Laguna.

In an interview, Antonio Darwish also pointed out that the so-called restingolitas are unique in the world in terms of the relationship between two radioactive elements such as uranium and thorium, and added that these statements makes them after learning the results of chemical and radiological analysis made to these rocks.

The concentration of uranium is in the white part of the stone, which is the inside, and that is very different chemically from the outer zone, which is black.

The white part has given levels of uranium that are at least six times higher found in any other volcanic rock of the Canary Islands, and are probably of the most radioactive in the world, said Antonio Darwish.

To compare the amount of uranium and thorium that have these stones thrown by the El Hierro underwater volcano, checks that it is somewhat unique in the world because it is usual that there is between 0.1 and 0.2 times more than the second, and in the case of the so-called restingolitas there are about three times more than the first.

This result indicates that it is material which has been subjected to a hydrothermal process, said the researcher, who added that in the world there may be between four or five rocks that have a similar composition.

However, in the crust or outside of the stone that has emerged in El Hierro uranium levels are different, which means that the source is different from the internal layer, he explained.

As regards the possible origin of the inner part of the Canarian Institute of volcanology (Involcan) scientists who collaborate with the University of La Laguna to make this study funded by the Council for Nuclear safety indicate that there are several possibilities.

Antonio Darwish expressed in the area where the underwater eruption occurred, and although El Hierro is a young island, there are seamounts of the Cretaceous, the time of the dinosaurs, and pointed out that the layer white is quite old material and could have at least one hundred thousand years.

The origin of the white part is hydrothermal, what means that some fluid was pumped uranium into this area of El Hierro and is remarkable for the fact that that layer it seems you sold out in a few weeks, said Antonio Darwish.

The inner part of the so-called restingolitas could also come from the oceanic Africa platform, or material of very ancient eruptions, landslides on the island of Tenerife, and even so it opens a new study in this regard, said Antonio Darwish.

This scientist expressed his concern at the fact that there has been looting of a rock which is unique in the world, because there are few signs of this stone that even if you have a high concentration of uranium is not dangerous because the quantities of the radioactive element are not significant.

Antonio Darwish noted that the value this stone gives uranium is "absolutely" rare and until the appearance of this rock which presented greater concentration of this element in the Canary Islands was the Tindaya mountains, on the island of Fuerteventura.,,

http://www.diariodeavisos.com/2012/08/04/actualidad/las-piedras-de-la-erupcion-herrena-de-las-mas-radiactivas-del-mundo/

[jand]

OT but interesting to read.

,,Mass grave in London reveals how volcano caused global catastrophe

Scientists search for the explosive source of a disaster that wiped out almost a third of Londoners in 1258,,


http://www.guardian.co.uk/uk/2012/aug/05/medieval-volcano-disaster-london-graves

[jand]

Whilst El Hierro seems to be quiet at the moment have just seen  this on the Avcan Facebook page re Fuerteventura.

,En el sur de Fuerteventura hemos sentido algo extraño hoy... Un ruido corto seguido de una pequeña vibración.
Pensaba que lo había sentido yo solo, pero mi hija que estaba al lado y mi mujer que estaba a unos 50 metros también lo sintieron.
Que raro!!!!

In the South of Fuerteventura we felt something strange today... A short noise followed by a small vibration.
I thought that it had felt I only, but also felt my daughter who was on the side and my wife that was 50 metres.
How strange! ,

http://tinypic.com/view.php?pic=25ivkp4&s=6

[jand]

Gran Canaria today:

http://www.01.ign.es/ign/head/volcaSenalesDiasAnterioresHora.do?nombreFichero=EOSO_2012-08-09_12-13&estacion=EOSO&Anio=2012&Mes=08&Dia=09&tipo=2&hora=12-13

[jand]

The situation in El Hierro has changed there have been quite a few shallow earthquakes today and this has been posted by Raymond Matabosch on his blog:

,,Eruption of El Hierro, 13 August 2012: "Residents (at El Hierro) can feel the vibrations, very short, dry jolts, and are experiencing dizziness, as well as, in Tigaday center, gassy odors, – in fact toxic odors – of rotten eggs, – H2S -, and of scratched matches, – SO 2 -, which are felt by the population ... there is no doubt that there is also the presence of carbon dioxide emission – CO2 -. We are not willing to be alarmist but the volcano risk level should be raised to at least yellow, if not to red ... no time to wait ... ",,

[jand]

1160768  13/08/2012  08:19:09  27.7745  -18.0956  14  1.4   4   W FRONTERA.IHI

• info
  
  
  1160750 13/08/2012  08:30:15  27.7619  -18.0773  10   1.7  4  W FRONTERA.IHI
  
  
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  1160762 13/08/2012 08:30:54  27.7663  -18.0802  10  1.6  4  W FRONTERA.IHI
  
  
• info
  
  1160764 13/08/2012 10:03:15  27.7390  -18.0433  10  1.3  4  W FRONTERA.IHI
  
  
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  1160769 13/08/2012  10:35:36  27.7048  -18.1505  19  2.3  4  SW EL PINAR.IHI
  
  
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  1160815 13/08/2012  13:15:34  27.7640  -18.0847  13   1.2  4  W FRONTERA.IHI
  
  
• info
  
  ign.es

[jand]

Important Update 13/08 – 16:26 UTC
After a period of relative weak to very weak seismic activity, the magma below El Hierro looks to start another episode as we cannot relate the 6 earthquakes today as stress phenomena. The epicenter of the earthquakes were in between 10 and 14 km, which means that if seismicity today is generated by magma, we have a totally different situation than at the end of June when we constantly has epicenters below 20 km. The location of the epicenters today where also different as the majority was located in the El Golfo Bay and a few others below the island and in the Las Calmas sea.
6 earthquakes so far today is not revolutionary, but at least interesting to give it a close watch
- The seismogram at CHIE does not confirm an increase of  the activity, but this can change swiftly as we know from the recent past
- The deformation data from Involcan and the Nogoya University also show an uplifting from a little less than a cm in both PINA and FRON (Ultra Rapid and we trust that the GPS data are still refreshed as it is hard to see on the graph.
- If deformation data and seismicity would continue to increase the following hours and days, we might have a new phase in the El Hierro volcano activity

www.earthquake-report.com

[jand]

Important Update 15/08 – 14:50 UTC
- Another 5 earthquakes have to be added by the already 6 mentioned earlier on, bringing the total to 11. Depth 11 to 12 km and the depth of the 06:46 quake still stands at 6 km ! Epicenters : close to Sabinosa or in the El Golfo Bay just north of Sabinosa

www.earthquake-report.com

There have been 13 earthquakes now and all below 13 km depth one earlier this morning was at only 6km .

On Avcan Facebook Page there are lots of recent  comments from the islanders too many to comment on but some people understandably are genuinely getting more worried.

[jand]

Update 15/08 – 14:50 UTC
- 4 more (3 new 12 km depth and 1 19 km). Amm the 12 km depth quakes were near Sabinosa, the 19 km depth quake to the west of of the western tip (location of the swarm who started at the end of June)

[jand]

The latest graph of released energy.

http://www.avcan.org/sismica/graficas/G1457.jpg?t=1345068068

[jand]

There have been over 40 earthquakes at El Hierro today listed below some comments below from earthquake-report.com.

Update 16/08 – 16:25 UTC
- 3 more earthquakes from M0.9 to M1.1 at a depth of 11 to 12 km (12:25 to 13:47 UTC)
- Maybe IGN could take a few courses in press reporting at GNS Science New Zealand. If an important new swarm starts, like the one today (even with weak earthquakes), an experienced volcanologist may write 5 sentences in explaining what the opinion of the organization is. Why does a body like Pevolca is to be used for volcanology ? If i would live in Sabinosa, i would love to hear a few words  if continuous quakes are occurring below my house.

Update 16/08 – 13:37 UTC
- 5 more earthquakes in between M0.6 and M1.2 and at depths in between 10 and 11 km


Image courtesy Avcan

Update 16/08 – 11:53 UTC
- We have to continue bringing updates on the seismicity below the island.
4 more earthquakes bringing the total on 32 today. Magnitudes from M1.0 until M1.5. Depths 10-11 km. IGN has updated his list up to 08:30 UTC
- At right a small map with the epicenters of a number of the latest earthquakes.

Update 16/08 – 09:50 UTC
- 1 earthquake has to be added since our latest update (07:29 – 11 km depth – Magnitude M 1.5)
- For your comfort, we have cut 2/3ths of this article. Parts 49 and 50 (yes 50!) have been archived. Links to all those 50 parts can be found at the bottom of this page.
- As seismicity will probably get stronger and stronger, we remind our readers that they can get an automatic email when these earthquakes are listed at EMSC (M2.5 or more). This is the text we have published in our earlier versions.

[jand]

1161303 16/08/2012 00:07:29 27.7407 -18.0710 10.2 1.2 mbLg W FRONTERA.IHI - El Hierro
1161304 16/08/2012 00:38:51 27.7545 -18.0817 10.7 1.0 mbLg W FRONTERA.IHI - El Hierro
1161305 16/08/2012 00:48:51 27.7527 -18.0716 11.0 1.0 mbLg W FRONTERA.IHI - El Hierro
1161306 16/08/2012 01:08:54 27.7534 -18.0766 9.4 0.6 mbLg W FRONTERA.IHI - El Hierro
1161308 16/08/2012 01:15:21 27.7567 -18.0712 10.1 0.8 mbLg W FRONTERA.IHI - El Hierro

1161307 16/08/2012 01:25:34 27.7487 -18.0461 11.2 1.1 mbLg SW FRONTERA.IHI - El Hierro
1161310 16/08/2012 01:39:25 27.7505 -18.0500 11.1 0.7 mbLg SW FRONTERA.IHI - El Hierro
1161313 16/08/2012 02:32:28 27.7077 -18.0750 18.4 1.6 mbLg SW FRONTERA.IHI - El Hierro
1161315 16/08/2012 02:33:56 27.7624 -18.0757 13.2 0.9 mbLg W FRONTERA.IHI - El Hierro
1161317 16/08/2012 02:54:29 27.7568 -18.0524 12.1 0.5 mbLg W FRONTERA.IHI - El Hierro

1161318 16/08/2012 03:02:33 27.7630 -18.0811 11.0 0.7 mbLg W FRONTERA.IHI - El Hierro
1161325 16/08/2012 03:08:23 27.7807 -18.0751 10.6 0.7 mbLg NW FRONTERA.IHI - El Hierro
1161319 16/08/2012 03:16:39 27.6920 -18.0614 11.0 0.9 mbLg W EL PINAR.IHI - El Hierro
1161326 16/08/2012 03:20:14 27.7714 -18.0767 10.9 0.6 mbLg W FRONTERA.IHI - El Hierro
1161324 16/08/2012 03:35:10 27.7594 -18.0784 10.5 1.3 mbLg W FRONTERA.IHI - El Hierro

1161322 16/08/2012 03:35:40 27.7663 -18.0823 11.1 2.2 mbLg W FRONTERA.IHI - El Hierro
1161320 16/08/2012 03:46:32 27.7707 -18.0778 10.5 1.4 mbLg W FRONTERA.IHI - El Hierro
1161321 16/08/2012 03:50:12 27.7568 -18.0749 11.7 0.8 mbLg W FRONTERA.IHI - El Hierro
1161323 16/08/2012 03:59:46 27.7772 -18.0778 10.6 0.4 mbLg W FRONTERA.IHI - El Hierro
1161327 16/08/2012 04:02:49 27.7683 -18.0781 10.6 1.5 mbLg W FRONTERA.IHI - El Hierro

1161328 16/08/2012 04:28:39 27.7685 -18.0774 10.3 1.4 mbLg W FRONTERA.IHI - El Hierro
1161329 16/08/2012 05:43:44 27.7636 -18.0788 10.6 1.5 mbLg W FRONTERA.IHI - El Hierro
1161330 16/08/2012 05:45:01 27.7435 -18.0797 9.9 1.3 mbLg W FRONTERA.IHI - El Hierro
1161331 16/08/2012 05:49:57 27.7414 -18.0773 10.5 1.4 mbLg W FRONTERA.IHI - El Hierro
1161332 16/08/2012 06:03:01 27.7576 -18.0870 10.5 1.2 mbLg W FRONTERA.IHI - El Hierro

1161374 16/08/2012 06:51:36 27.7620 -18.0719 11.1 0.7 mbLg W FRONTERA.IHI - El Hierro
1161345 16/08/2012 07:00:38 27.7647 -18.0846 11.6 1.6 mbLg W FRONTERA.IHI - El Hierro
1161360 16/08/2012 07:03:26 27.7369 -18.0868 10.6 0.8 mbLg W FRONTERA.IHI - El Hierro
1161366 16/08/2012 07:10:37 27.7527 -18.0834 10.7 0.8 mbLg W FRONTERA.IHI - El Hierro
1161370 16/08/2012 07:26:19 27.7419 -18.0739 10.8 1.1 mbLg W FRONTERA.IHI - El Hierro

1161368 16/08/2012 07:26:36 27.7339 -18.0696 10.5 1.0 mbLg SW FRONTERA.IHI - El Hierro
1161350 16/08/2012 07:29:36 27.7606 -18.0798 10.7 1.5 mbLg W FRONTERA.IHI - El Hierro
1161371 16/08/2012 08:11:45 27.7471 -18.0788 9.7 1.2 mbLg W FRONTERA.IHI - El Hierro
1161354 16/08/2012 08:30:01 27.7573 -18.0733 10.8 1.4 mbLg W FRONTERA.IHI - El Hierro
1161378 16/08/2012 09:25:38 27.7510 -18.0787 9.9 0.9 mbLg W FRONTERA.IHI - El Hierro

1161380 16/08/2012 09:44:37 27.7498 -18.0605 1.00 0.6 mbLg W FRONTERA.IHI - El Hierro
1161372 16/08/2012 10:41:22 27.7727 -18.0862 11.6 1.2 mbLg W FRONTERA.IHI - El Hierro
1161400 16/08/2012 12:25:06 27.7571 -18.0772 11.3 0.9 mbLg W FRONTERA.IHI - El Hierro
1161420 16/08/2012 12:56:48 27.7541 -18.0835 10.5 1.1 mbLg W FRONTERA.IHI - El Hierro
1161421 16/08/2012 13:47:22 27.7592 -18.0883 12.2 1.1 mbLg W FRONTERA.IHI - El Hierro

1161422 16/08/2012 15:29:20 27.7619 -18.0828 11.1 1.3 mbLg W FRONTERA.IHI - El Hierro
1161423 16/08/2012 15:39:17 27.7531 -18.0470 11.7 0.6 mbLg W FRONTERA.IHI - El Hierro
1161424 16/08/2012 16:05:46 27.7589 -18.0748 10.5 1.2 mbLg W FRONTERA.IHI - El Hierro
1161425 16/08/2012 16:18:06 27.7617 -18.0801 11.0 1.4 mbLg W FRONTERA.IHI - El Hierro
1161427 16/08/2012 18:11:04 27.7575 -18.0499 11.6 1.0 mbLg W FRONTERA.IHI - El Hierro

[jand]

Update 17/08 – 15:22 UTC
- The frequency of earthquakes looks to subside for the last couple of hours. 2 more since our latest update. 1 of M0.6 at 12:06 at a depth of 10 km and a M1.8 at a depth of 9 km at 13:05. We still see at lot of micro-seismicity on the seismograms, which means that there are a lot of earthquakes but too weak to be measured.

Update 17/08 – 12:19 UTC
- Another 2 quakes have been added to the 12 reported earlier. Magnitudes (from 1.1 to M1.3) – Depths : 11 km – Timeline : 09:20 until 09:49
- The local El Hierro press is (of course) busier with the massive fires on the other islands than with the current earthquake swarm. Obviously the local press seem to look only to the +1.5 earthquakes !

Update 17/08 – 10:01 UTC
- As said in our 07:37 update, we were very surprised to see no more earthquakes after 18:11 and a restart of seismicity after midnight, even more that we saw continuous peaks on the seismogram during the late evening ! The reason : IGN had probably no personnel at hand to add the quakes (we guess that they are entered manually in the database). The 58 quakes listed now are registered up to 23:37. We do not expect any further change.

Update 17/08 – 10:01 UTC
- Another 5 quakes have been added to the 7 earlier reported. Magnitudes are going up (range from 1.1 to M2.1) – Depths : 10 to 13 km – Timeline : 06:54 until 08:39

Update 17/08 – 07:37 UTC
- A little bit to our surprise, there were no more earthquakes listed yesterday after 18:11. This brings yesterdays total on 45.
- The quakes continued though after midnight and so far today we have noticed 7 volcanic earthquakes (see list below). Epicenters are still in the same perimeter.
- Vertical deformation both at El Pinar and Frontera stations is slightly higher which corresponds with the many, mostly weak earthquakes in the El Golfo area. The SABI station (Sabinosa) of the University of Nagoya does not seem to report data anymore, a pity as almost all the current action takes place in that sector.


www.earthquake-report.com

[jand]

There have been 2 earthquakes near Tenerife which have been felt over a large part of the island. The comments of the islanders can be found on the Avcan Facebook page (there are too many to quote) .

1161577 18/08/2012 01:52:59 28.5119 -16.5023 25 Sentido 2.6 mbLg NW EL SAUZAL.ITF

• 
  1161576 18/08/2012 01:50:51 28.5303 -16.5133 27 Sentido 3.8 mbLg NW EL SAUZAL.ITF
• 
  
  Image courtesy of Avcan.
  
  

[jand]

Update 18/08 – 09:24 UTC
- Those people who had subscribed to earthquake emails in Spain or the Canary Islands, received a couple of alerts during the European night.  We wrote this earlier today in our earthquakes section : 3 earthquakes close to western Tenerife (Canary Islands) – The earthquakes epicenter was close to La Laguna. An ER reader specidied that the shaking of the mainshock lasted for about 5 seconds. The shaking was weakened somewhat because of the double effect of the depth (more than 20 km deep) and the location of the epicenter (below the sea bed)
- In the meantime the magma quake engine below El Hierro has started again; Contrary to what happened the last couple of days, the depth of the quakes is very different (from 3 to 37 km !), something to watch closely. The 3 km depth earthquake is very weak and can have been caused by stress in the island
- The vertical deformation at Frontera has deflated by at least 1.5 cm in 24 hours (Ultra Rapid GPS data University of Nagoya)

www.earthquake-report.com