This is Part 7 of the El Hierro Volcano eruption report
Our tweets are also posted into our Facebook Volcano Page
With the collaboration of Joke Volta, an El Hierro resident
Read also : Scientific paper reveals massive historic Tenerife volcano flank collapse
Read also: Economic impact on El Hierro and the Canary Islands if an aerial eruption would occur
Read also: Part 1 (from July 28 until early September)
Read also: Part 2 (from September 25 until October 10 )
Read also: Part 3 (from October 11 until October 13 )
Read also: Part 4 (from October 14 until October 17 )
Read also: Part 5 (from October 18 until October 21 )
Read also: Part 6 (from October 22 until October 26 )
Read also: Part 7 (from October 27 until October 31 )
Read also: Part 8 (from November 1 until November 3)
Read also: Part 9 (from November 4 until November 6)
Read also: Part 10 (from November 7 until November 8)
Read also: Part 11 (from November 9 until November 11)
Read also: Part 12 (from November 12 until November 15)
Read also: Part 13 (from November 16 until November 19)
Read also: Part 14 (from November 20 until November 23)
Read also: Part 15 (from November 24 until November 27)
Update 03/11 - 23:45 UTC :
Earthquakes are getting stronger again. Just recently at 23:06 a quake at 22 km depth measuring M 3.2 occurred NW of Frontera (the first one today above 3).
Update 03/11 - 22:53 UTC :
The pictures below are courtesy of the Presidencia del Gobierno de Canarias
These pictures have been taken out of a helicopter and are showing the November 3 jacuzzi (burbuja in Spanish). No green stain today but the grey muddy color is present. It looks to us that the new spot is at a bigger distance from the coast.
Click on the pictures to see them at full size - images courtesy Presidencia del Gobierno de Canarias
Update 03/11 - 22:50 UTC :
We have been telling our readers a couple of times about a very interesting volcano discussion forum at jonfr.com. One of the people commenting on what is happening is Peter Cobbold. As nobody knows exactly what is going on below the volcano or in the Las Calmas sea, we are all searching for the probable truth. Let's give Peter a chance to unfold his jacuzzi theory.
Scientists are doing a difficult job and have not had the best equipment. At the start of the jacuzzi they only had one site recording tremor ( CHIE) so could not locate its source. Now with the additional stations – the ones where we are denied access- thay have an ability to locate the tremor source approximately, even in depth. From the brief view we had of the data from those other stations it was clear that the tremor was strongest in the south, and is probably not associated with the deep earthquakes under el Golfo.
The frequencies that dominate the tremor on CHIE are around 1 to 5Hz as we can see from the yellow and red bands on the plot:
These frequencies are typical of hydrothermal tremor
( Review on tremor here: http://epic.awi.de/11598/1/Kon2003a.pdf - section 4.3.)
So I see the jacuzzi being a conduit of km scale that that fills with sea water which then boils and erupts periodically under steam pressure to cause the bursts of amplitude on the CHIE plot. The photos of the grey stain show a well defined periphery as if a jet of water has been pushed up in a geyser-like fashion, whereas a jet of gas would I think have a more diffuse, and bubbling, appearance. A few weeks back the jacuzzi was described as pulsing every 15 minutes. It would be useful to know if the gray stain expands periodically now, perhaps in time with the CHIE pulses.
I offer these thoughts as an amateur.
Update 03/11 - 20:44 UTC :
Pevolca has decided not to change their opinion. No evacuation will be organized and they stress that there is NO risk for the population at the moment (source Diario El Hierro).
Update 03/11 - 19:30 UTC :
- 96 species of fish have been affected by the eruption. There are no signs of any marine life within a radius of 1.5 km from the eruptive mouth. In an extended radius of 3 miles, there is almost no marine life perceivable until a depth of 200 meter. Below 700 meter depth and further than 1.5 mile from the eruption vent, marine life is not affected anymore. The results have been reported by Marine professor Alberto Brito from the University of La Laguna, Canary Islands.
- The people responsible for the webcam at El Golfo (LasPuntas.es) (the one directed to the mountains) have reacted on our request to change direction in El Golfo and to install another one towards the Las Calmas sea. The owner of the webcams is a Canary Island professor of geography and history who was born in La Frontera. He wrote :
* In two days will have a camera to the sea of El Golfo.
* I will try to put camera in Las Calmas but is very difficult.
- 30 earthquakes today were greater than M 1.5, a lot less than yesterday
Data update 03/11 - 19:20
- Harmonic tremor continues to be very strong and indicates that the eruptive process increases again.
- The quakes became weaker when the harmonic tremor strengthened. This also happened with the first Jacuzzi or burbuja episode.
- Pevolca is still together discussing the present situation
Very Important RapidEye News
We talked on the phone a couple of hours ago with a responsible of RapidEye, the commercial satellite company who had published the outstanding satellite pictures earlier on. Mrs. Douglass, working in the Marketing communications department in Brandenburg, Germany, told us that the technicians are currently working on assembling 2 new images. If good enough to show (the images are only of an acceptable quality without clouds or only a thin dispersed cloud cover), they will be online tomorrow morning.
"Once again we stress that we do NOT understand why the Spanish government or the European Union scientific instances are not ordering these HD images as they are a VERY IMPORTANT element for analysis. The NASA Modis and Terra satellite images are only offering 10% of the quality of the RapidEye images. "
Important Update 03/11 - 14:54 UTC :
PEVOLCA has called a meeting for today 18:00 (local time) to discuss the present situation
Update 03/11 - 14:52 UTC :
We have a hard time in following all the events. Joke just told us that the TV Canarias showed helicopter images while overflying the new stains.
Update 03/11 - 14:25 UTC :
The pictures below are from the new green-yellow stain in the Las Calmas sea. The stain could well be observed from La Restinga and from the viewing point at Arena Blanca.
The second picture is a thumbnail from the new Jacuzzi as it appeared a short time in the Las Calmas sea. DiarioElHierro photographer Gelmert Finol was on the watch and could take the picture.
The first picture has apparently been taken yesterday (there is confusion about it) and the second picture from this morning.
Update 03/11 - 13:45 UTC :
Earthquake-report.com is bringing news as it reaches us. If we are not completely sure on some facts, we will let you know. As the human interaction in very important during these events, we feel that withholding news from our readers is the bad way of dealing with ongoing events.
- Pevolca has said that it has NOT called for an evacuation as the magma movement and registered earthquakes are far too deep to generate an immediate risk.
Update 03/11 - 13:17 UTC :
In our 12:02 update we brought the story of Joke's friend who was packing her luggage @ La Restinga. We doubted a little later whether it was a mandatory evacuation of a decision from herself. Well it was the latter, but she is followed by other residents of La Restinga at the moment. The La Restinga people seem to auto-evacuate, a known factor for many people around the world. This happens when they have no 100% certainty of what is safe or not, especially during earthquakes.
Pevolca still meets at the moment to discuss the latest data.
Very important Update 03/11 - 12:13 UTC :
Jill, one of our many readers just attracted our attention to an article in the Canarias7.es. Canaria7. es wrote shortly ago that the burbuja or jacuzzi, as the islanders call the eruption spot, has been active for a while. A scientist has been flying to the spot by helicopter and the burbaja was well seen from Arena Blanca, a viewing point in between El Pinar and La Restinga. Canaries7 says also reports that Juan Manuel Santana denied an evacuation order at this moment.
Very important Update 03/11 - 12:02 UTC :
Joke has just called her friend at La Restinga. A lot of movements are going on + the burbuja (Jacuzzi) seems to be back again (not confirmed message in DiarioElHierro). Jokes friend is packing her luggage, she said. But at the moment we do not know whether it is her own decision or a mandatory evacuation.
The information we are getting is conflictual (facts combined with apparently rumors). The question mark in the title is very important.
We expect a message from Pevolca with their current estimate of what exactly is going on soon. Joke is questioning a lot of people in El Pinar and has called some people
Update 03/11 - 11:23 UTC :
PEVOLCA reported that they are currently screening all available data and that they will call for additional measures if they feel it appropriate to do so. They also reported that the people of La Restinga have felt multiple tremors
Important update 03/11 - 10:34 UTC :
A new event is in the making or did happen a while ago. Both harmonic tremor and frequency have changed. We reckon that scientists will explain their opinion later on. The current harmonic tremor graph is at max. (flat horizontal lines).
The number of earthquakes is considerably less than during the same period yesterday.
Update 03/11 - 09:07 UTC :
A further climb in harmonic tremor since a number of minutes. The frequency of the tremor has hardly changed since many days. A sharp change in frequency (the colors in the lower part of the graph) will probably coincide with a new "event" (not necessarily a new "vent").
Overview update 03/11 - 08:47UTC :
In an attempt to give a better view on what we are describing about harmonic tremor in many updates below, we have assembled the data of the last 3 days.
FYI - Wikipedia description of Harmonic tremor : Harmonic tremor describes a long-duration release of seismic energy, with distinct spectral (harmonic) lines, that often precedes or accompanies a volcanic eruption. More generally, a volcanic tremor is a sustained signal that may or may not possess these harmonic spectral features.
A harmonic tremor is a sustained release of seismic and/or infrasonic energy typically associated with the underground movement of magma and/or venting of volcanic gases from magma. Being a long-duration continuous signal from a temporally extended source, a volcanic tremor contrasts distinctly with transient sources of seismic radiation, such as tremors that are typically associated with earthquake and explosion.
Overview update 03/11 - 08:12UTC :
- Pevolca has announced yesterday evening that based on yesterday's data, they could not conclude that an eruption is imminent.
- Increasing harmonic tremor and a turbulent seismogram are contradicting the words of Pevolca. The IGN scientists at Pevolca have however a lot more data than published on the IGN website. (see below)
- Some of the more experienced amateur volcano followers ( Iceland volcanoes) @ jonfr.com have other opinions, although they admit that not having all the data is a problem to have a truly good view on the situation. The discussions go often very deep and tend to become very technical.
- One of the problems for scientists is that the past Surtseynian eruptions like the ones that happened in Iceland and in the Azores, are not as documented as eruptions are today, which make comparisons rather difficult.
- Earthquake-report.com wants to thank the many readers who are writing us with tips, local contact persons, etc. This help is not only appreciated but essential to verify upcoming events.
- IGN has listed 19 earthquakes since midnight, the strongest one being a 2.7 to the West of Frontera. The depth varies in between 12 km and 22.10 km. Nothing special one would say, but harmonic tremor is indicating constant magma stress below the volcano.
Update 02/11 - 23:43 UTC :
- IGN server seems to be under heavy load today.
- harmonic tremor is getting stronger and stronger (see graphic below). The vertical spikes are the earthquakes as listed in the IGN earthquake list.
- some strong graphic bulges are not earthquakes and have not been explained so far by scientists. Amateur volcano follower panels and AVCAN are talking about strong magmatic action looking for a way to escape, but luckily not finding it at the moment unless in the Las Calmas sea
- We do not understand why we have NO daily RapidEye satellite picture. The cost of it is peanuts compared to the cost of the present operations. RapidEye was to our knowledge the only means of detecting the different stain colors and the eruption area. Weather permitting RapidEye can take at least a daily HD image.
Update 02/11 - 18:45 UTC :
A strong earthquake with a magnitude of
3.8 4.4 (after revision) occurred at 18:10 UTC at a depth of 23 km. Epicenter was in the El Golfo bay. It was felt by the islanders.
Update 02/11 - 17:29 UTC :
- AVCAM has counted 85 quakes since midnight UTC today
- The IGN - CHIE seismogram showed a big unexplainable bulge around 15:18 UTC. The phenomena is not showing up in the earthquake lists, but can be seen almost as strong as this morning 4.3 earthquake as a spike on the harmonic tremor graph. Lesser bulges are appearing more and more on the graph.
Update 02/11 - 14:00 UTC : Joke Volta and her friends, the El Hierro human webcams :
Joke Volta, our El Hierro contact (living more than 25 years on the island), has a friend in the El Golfo area and another one living at La Restinga. Both friends have their binoculars almost next to them to search the sea for eventual new events when Joke is asking them to do so. As we have no webcams on both spots (Mr. Alpidio Armas, we live in 2011!), the human webcams have to do the job. On behalf of our readers we thank Joke and her 2 friends to keep us updated from El Hierro.
Oh yes, they haven't noticed anything special in the sea today.
Overview update 02/11 - 14:00 UTC :
The strong earthquake this morning was updated and recalculated by scientists to 4.3 (from 4.0). This is a big difference in energy.
- Involcan has reported that the amount of CO² in the air at El Hierro has never been so high than now. CO² in the air is part of the pre-eruptive signals. Click here to read the in-depth article in the Diario de Avisos (Spanish).
- Fish have disappeared completely from the Las Calmas sea (the sea south of La Restinga were the green stain and jacuzzi were observed).
- The PEVOLCA scientists had plans to visit the El Golfo area this morning, after a serious increase of the seismic activity in that area. The investigation will also look at the situation of the people living in that part of the island. Later today the current measures will be evaluated again on the basis of today's findings.
- The earthquake list on the IGN website is far from complete. there are more than the 53 listed earthquakes so far.
Update 02/11 - 13:12 UTC :
Diario El Hierro writes that the analysis of the recently found lava stones found in the Las Calmas sea, reveals the possibility of a major explosive character eruption.
The University of Barcelona who analyzed the samples said that the found lava was NOT of the a Surtseynian type, the kind of eruption everybody expected so far.
Update 02/11 - 11:09 UTC :
- IGN had listed 2 shallower earthquakes, 1 at 1 km depth (south of El Pinar) and 1 at 3 km depth nw of Frontera .
- both quakes have been recalculated and revised / deleted (instrumental errors are common in earthquake measuring)
Update 02/11 - 09:09 UTC :
The UME (Unidad Militar de Emergencias = Military Emergency group) has announced that it has transported the necessary equipment to El Hierro to build a shelter with a capacity of 2,000 people, in case that a quick evacuation would be needed. The equipment was brought to El Hierro on the request of Pevolca. The shelter will have all necessary compartments like shops (...), dining room and services.
Material to install a shelter to accommodate 500 people and belonging to the Red Cross is already on the island, ready to be used immediately.
PEVOLCA has stressed that the shelter equipment is one of the many measures to be prepared if a worst case scenario would come true.
The shelters have not been installed so far because nobody knows the location where an eruption would be occurring, if it would occur. The most probable spot would be the current eruptive Las Calmas eruption crater as showed on the Ramon Margalef topographic 3-D image below, but the current set of earthquakes are occurring below the El Golfo bay. Pevoca is this prepared for everything.
Important Data update 02/11 - 08:27 UTC
Rather constant but still strong harmonic tremor (might change after the strong quake).
The magnitude 4.0 earthquake occurred a little while ago and is the strongest earthquake since the 4.4 earthquake on October 8. The earthquake occurred at a depth of 20 km in the bay of El Golfo. The earthquake was of course felt by the islanders.
Update 01/11 - 23:30 UTC :
Harmonic tremor is further increasing. Harmonic tremor is one of the most important pre-eruption signals. It is is still not as strong as it was before the opening of the Las Calmas / La Restinga vent, but if it continuous to grow tomorrow it can be meaningful.
Update 01/11 - 15:47 UTC :
Everybody is really excited about the video who was recorded by the Roman Margalef Liporos 2000 ROV (when where , there is no comment together with it). We have been maybe one of the loudest callers to have the ROV in the eruption waters, but the result is a little disappointing to us . What we have seen in the meantime via the RapidEye satellite images was as convincing as what we see now on the Margalef video images. We hope, of course, to see additional footage from the Roman Margalef the coming days because he has great instruments with him.
Very important update 01/11 - 16:32 UTC :
The earlier (erased) video and the image proved to be NOT an eruption vent. We were able to conclude this after very intensive contacts with our readers and people at the island. The grey turbulent spot seems to be landmass (see picture below). We thank our many users in adding evidence to exclude the eruption has taken place.
We have erased all information indicating a possible new eruption vent, to exclude further confusion.
Update 01/11 - 16:12 UTC :
Earthquake-report.com trusts on the expertise of Pevolca and we are sure that they would immediately call a meeting if something special would have been noticed.
Data Update 01/11 - 10:37 UTC :
In our 08:19 update we mentioned a stronger harmonic tremor signal being recorded. We have to report that the harmonic tremor became even more stronger the last couple of hours (see below). A very strong harmonic tremor would increase the chance on an eruption considerably. The last earthquake IGN has listed was at 07:18 UTC. It is hard to believe that this list is complete at the moment.
Update 01/11 - 09:16 UTC :
X updates ago we stressed on this page that a quick evacuation of the El Golfo bay area could be jeopardized by the blocking of the Los Roquillos tunnel in the event of a major +4.5 earthquake. Our scenario was feeded by the fact that the authorities closed the Los Roquillos tunnel during the first half of October out of rockfall / landslide fears.
In a document written by the Instituto Geográfico y Minero de España (IGME) is stated that the tunnel is no longer safe for magnitudes greater than 4.5. (source Diario de Avisos)
People who are unfamiliar with volcanic bursts / eruptions have to know that major eruptions almost always coincide with a strong earthquake. We are sure that Pevolca would take action if such a situation would be imminent.
Important update 01/11 - 08:19 UTC
- Scientists have found large smoking lava in the Las Calmas sea in front of La Restinga (earlier jacuzzi area).
- It is hard to believe that we still do not have a webcam (and/or time lapse camera) directed on the stain. Such a camera would not only be great for us followers, but also for science. The Sakurajima volcano is a good example for the results.
- The currently installed webcam @ Frontera should be directed towards the El Golfo Bay during the current events.
- The University of Cadiz has said that the deformation is decreasing in the south because of the eruption and is gradually increasing in the El Golfo area (earthquake area). The university of Cadiz is cannot rule out a possible eruption in the Frontera bay area (ER: nobody can rule out anything at the moment. All instances are making their best guess, a volcano is unpredictable as where and when he/she will erupt. A major earthquake (M 4.5 to 5.5) may put events in a final direction or it may simple stop suddenly.)
- Yesterday was the most seismic active since October 8 - 153 earthquakes were counted and 6 were greater than M 3
- Today a new 3.9 magnitude quake was felt at 04:15 UTC. 2 quakes were greater or equal to M 3
- a stronger harmonic tremor has been recorded since 07:00 this morning (see below at the end of the graphic).
Update - a very similar situation as at Faial (so far)
Diario de Avisos has written an article that, for those who know Spanish is very interesting to read and for those who do not read Spanish interesting to look at. The birth of an Azores Island. The similarities with the present situation @ El Hierro is astonishing. The stain, the jacuzzi and a surtseyan eruption with the creation of a new island were all present at Faial, one of the Azores islands. Click here to read this outstanding article.
The explosive eruption took place in front of the village of Capelinho, Faial. @ Capelinho everything started with 10 days of seismic activity. Afterwards a green stain followed by a jacuzzi and a grey spot appeared in the ocean (identical phenomena have been seen so far at La Restinga (see below)).
On September 27 1957, a enormous column of combined steam, gases and ash did burst up to 1000 meter high out of the ocean. The diameter of the explosive area was approx. 300 meter! The following days 3 small islands were formed. The continuous activity added more material to the islands which grew together in 1 bigger island approx. 400 meter out of the coast. The eruption phase finally stopped at October 24 1958, more than 1 year later. After the eruption a big part of the island was covered with ash and the earlier formed island did grow gradually to become a part of the main island. A portion of 2.4 square km were added at Faial.
Video of the Capelinho Faial surtseyan eruption