El Hierro eruption (continued – 1)

El Hierro eruption (continued – 1)

Update 30 January: There has been a significant increase in the number of earthquakes over the last few days, with 11 today alone. Since many of these are under land (see some of the most recent locations in the map above), vulcanologists say that even with magma continuing to flow from the main vent, the pressure is building below the island. The harmonic tremor has been variable but, since last evening it has strengthened and maintained its level.

Throughout today there has been a great deal of smoking lava on the surface of the Las Calmas sea, almost like a show for the Prince and Princess of Asturias, who have been visiting the island on the Prince’s birthday in a show of support.

Update 25 January: In the last week, the harmonic tremor has been up and down, sometimes collapsing completely and at other times giving some extremely strong bursts. There have been several minor earthquakes … 8 the other day, 4 today so far. There has been bubbling on the surface, and quite a bit of smoking magma coming up … some of quite a size too.

Vulcanologists are still expecting it to become Surtseyan in type, but are saying it could be anything between hours and weeks before it goes up. There are science boats on the scene, Guardia Civil helicopters hovering over it taking measurements of temperature and gases being released….

One interesting bit of information was that the temperature inside the smoking maga is 426°C, said to be sufficient to allow the gases to ignite when they mix with oxygen at the surface. Another fascinating fact is that this undersea volcano has already released 12 times as much magma as the La Palma eruption that it is usually compared with.

Update 19 January: Pevolca says that bathymetric readings taken by the science ship Ramón Margalef on 10 and 11 January show that the cone is now at a depth of 130 metres – just 30 metres short of the height where Surtseyan activity could take place. The readings also show a significant growth in volume of the cone.

Update 18 January: Just as an update, there’s very little change in the eruption. Over the last ten days there has been an almost constant harmonic tremor, collapsing at some points but then building up. Vulcanologists think that this represents occasional vent collapses. Since last night there has been a very strong and almost constant harmonic tremor indeed, with a large area of staining on the surface of the sea. The eruption is ongoing.

Update 7 January: The Telefonica webcam HERE (click on the “Vista La Restinga Zona erupción” webcam at the south of the island) is showing steam/gas floating on the surface of the Las Calmas sea. This, vulcanologists are saying, could be the beginning of a Surtseyan eruption if this carries on growing and erupting in this way.

Update 5 January 2pm: Just in case of misinformation …..

Four small earthquakes were registered this morning in the Guimar-Candelaria area in Tenerife. These are not connected with the El Hierro eruption and are the magnitude and location are quite normal.

Update 5 January: More glowing lava appeared on the Las Calmas surface overnight, as seen in this video.

[youtube]http://www.youtube.com/watch?v=5PbEidSNOOc[/youtube]

Update 3 January 10pm: Here’s the video from that flyover:

[youtube]http://www.youtube.com/watch?v=lTovJueusQ0[/youtube]

Update 3 January: There is more bubbling in the Las Calmas sea today, and more Restingolitas smoking on the surface. The above incredible photo showing the area was taken in an Involcan/Guardia Civil flyover yesterday. The scale of it is clear compared to the little town of La Restinga on the coast.

Update 1 January 2012: There was a swarm of seven minor earthquakes overnight, the largest being 2.5, with a further two close together late this afternoon, when the harmonic tremor picked up, becoming very strong. Throughout the day there has been bubbling on the Las Calmas sea and a very large magma stain, with more “Restingolitas”.

Update 31 December: This morning the harmonic tremor is up and down, mainly subdued, but there is again a bubbling sea with smoking lava appearing at regular intervals. Since 10.30 or so this morning, plumes of steam and large lumps of smoking lava are clearly visible.

Update 29 December: A minor harmonic tremor resumed last evening which continued through the night, and there’s a stain on the surface of the Las Calmas sea this morning with bubbling in the centre. There have been a few earthquakes in the 1 and 2 grade range as well. The eruption is still going.

Update 28 December: Very little has been happening over the last several days. The harmonic tremor has been up and down a bit every day, but at a very low level. Today, however, there is no longer any harmonic tremor being registered at all, which means that, at least for the moment, the eruption has stopped completely. It is possible, of course, that pressure will build up again, and earthquakes would indicate that was happening, but with the harmonic tremor flat-lining and no earthquakes, it is over.

Update 22 December: The harmonic tremor has been up and down quite a bit over the last couple of days but is now going down very quickly. Scientists think this is now subsiding to a stop over the next few days. The deformation in the south is also going down, in line with the harmonic tremor. This is a highly volcanic area so there will be future eruptions, but it really does look like this particular one is coming to an end.

Update 20 December: Over the last few days, there have been a very few small earthquakes, and a continued harmonic tremor. The only real news of any change is that scientists think the main vent has probably stopped erupting with magma coming from the side vents. It does seems to be dying down overall.

Update 17 December: There are mixed signals coming from El Hierro.

There is a constant if slightly-increasing medium harmonic tremor throughout the night with some short bursts, but its strength now seems to be decreasing fundamentally after every strong burst.

There again there has been a 2.3 tremor 22km under Los Llanillos in the El Golfo area, and there is a faint bubbling in the Las Calmas area, with a stain on the sea surface.

It’s impossible to guess which way this is going.

Update 15 December: well I hope they know what they’re doing. Pevolca have announced that they are stopping 24 surveillance, based on an assessment that nothing much more will happen. The Center for Permanent Care (CAP) in La Restinga will now open between 8am and 8pm every day, but if anyone sees anything, they can ring an emergency line, it seems. The number is 696 129 355.

Update 14 December: This won’t look much, but I think it’s very much more than it looks! Watch the first 20 seconds of the video below. It’s filmed at night so there’s nothing to see except the lights of La Restinga harbour. The sea beyond the harbour wall is black, but at 11 seconds in the video, you’ll see it, and there’s a second one too … glowing magma above the surface of the sea. And it fits exactly with a huge spike in the harmonic tremor graph, which I’ve posted at the bottom.

This morning, the eruption webcam shows smoking material on the surface, and air quality readings show a marked spike in sulfur dioxide, nitrogen dioxide, and other nitrogen oxides … the readings are double or triple the usual.

The current harmonic tremor as at 10am is very strong.

[youtube]http://www.youtube.com/watch?v=zV5wGToiVZ0[/youtube]

eh-13122011-6

Update 13 December: There has been a very powerful and turbulent bubbling throughout the day, with “degassing bubbles” visible on the surface. Still no earthquakes being registered. Some vulcanologists say that suggests the underwater volcano has become high enough so that the bubbles from the vent gas reach the surface; the lack of tremors could be the eruption dying away but this is contradicted by the continued harmonic tremor and volcanic growth. If it is not dying away, then the lack of tremors is of considerable concern, indicating a build up of pressure. Not a word from the authorities who said everything is returning to normal.

Update 12 December: Over the last couple of days there have been no earthquakes and a continued and unvarying medium harmonic tremor with some extremely strong bursts. To some extent, this feels like watching a ticking bomb.

Update 10 December: It seems that there could come a point in the next couple of weeks or so when the authorities regret implying things were “returning to normal”.

Diario de Avisos yesterday published an interview with Alpidio Armas, president of El Hierro. Obviously informed by various scientists, Sr Armas said that the Las Calmas volcano grew 80 metres over the last couple of weeks, a growth measured by the oceanographic ship Ramon Margalef.

Based on this figure, earthquake-report says that if the eruption continues at the present rate and in the same vent, it will take just a fortnight at most to arrive at a depth less than 100 metres. That is the point at which the water is shallow enough to produce very strong bubbling and steam plumes during the hydromagmatic bursts.

The report continues that if the same process carries on for another month, then we could expect regular hydrovolcanic explosions during the bursts, and thereafter the eruption may become spectacularly Surtseyan.

There has been a medium harmonic tremor for the last few days, and the eruption is very clearly not over.

Update 9 December: It’s laughing at them now …

This morning sees continuing Jacuzzi action this morning with a medium harmonic tremor.

Update 8 December: … and as if to prove the politicians wrong, a very strong harmonic tremor started at 10pm last evening. Moreover, it lasted minutes at a time rather than just quick bursts as previously. Vulcanologists say that this indicates a constant eruption activity. The tremor suddenly collapsed at 4.24am this morning.

That could be a final swansong from the new volcano, or a prelude to a new build-up. Since the harmonic tremor started picking up again around 7am this morning, followed closely by smoking lava on the Las Calmas surface around 7.30am, it seems that it’s not over for the moment.

This clearly suggests that they really don’t know what is happening, and adds great support to the claims of some concerned residents and scientists that yesterday’s news release was politically motivated and risky.

Update 7 December: The Canarian Government issued a press release just before 4pm this afternoon, the key points of which are:

Due to the reduction in seismic activity, and the downward trend in measurable deformation, though this will continue to be monitored:

  • The red alert for La Restinga has been lifted. It now joins the rest of the island on yellow alert.
  • The Las Calmas sea area, where the bubbling and smoking lava has been visible on the surface, is the only area that is now on red alert, and it remains a maritime exclusion area.
  • Boats can now enter La Restinga harbour again.
  • A “navigation passage” of 0.25 miles has been created along the coast to allow boats to pass from La Restinga to the north.
  • Despite reports of strong sulphur smells, air quality appears within normal limits. This too will continue to be constantly monitored.
  • Seismic measurements and bathymetric scans indicate that there is just one vent, though in the form of multiple cones at a depth of between 150 to 180 metres. The smoking lava emitted is being analyzed and results are awaited to provide information on anticipated evolution of the vent activity.

Reactions to the press release are mixed on El Hierro, with some saying this is a political decision. One major argument is that if the situation is still active enough to warrant a red alert in the Las Calmas area, and the emissions are at a depth of only 150m, then the situation is not secure enough for these measures.

Update 6 December: Just a general update.

Some scientists think this is now dying down and coming to an end, and certainly the authorities are beginning to behave as though this is the case. There is even pressure forming on them to lift the red and yellow alerts and for “things to get back to normal”.

Others, though, are very concerned that there is a political and economic motive behind this. There is clear worry in some quarters that the Los Roquillos tunnel is unsafe, and one prominent vulcanologist said yesterday that the eruption in a general sense is very very far from over, though it might shift from the specific Las Calmas sea area.

Meanwhile, the number of earthquakes has decreased, which is seen by some as proof that it’s all calming down, but by others as a worrying potential build up of pressure. The harmonic tremor is up and down like a yoyo, and this morning there is more smoking lava on the surface of the sea.

We are still waiting for the results of the sea-bed mapping exercise.

Update 29 November 11pm: There is a new development tonight.

A phenomenon like a steady pulsing known by the name of drumbeats started at 4.15 this afternoon. It is so called because it sounds like a rhythmic drumbeat, and it was first discovered in 2006 at Mount Saint Helens, the American volcano that erupted with gigantic force in 1980.

In the Mount Saint Helens case, it appears that a vast plug of rock was being pushed inexorably upwards by magma from below, creating mini-earthquakes as it went. These mini-earthquakes have been happening over the last few days in El Hierro too. And now the drumbeats have started.

It is important to note that the Mount Saint Helens drumbeats started well after the enormous eruption there, and so nothing similar is anticipated in El Hierro’s case. They are said, anyway, to be very different volcanoes. None the less, the drumbeats process itself is being repeated in El Hierro.

It is not yet known what the result of this will be. One possibility is that of a magma “plug” being pushed up and expelled; another is that of a new fissure being created with further eruption points. The drumbeats need to be located before any clear picture emerges.

Update 29 November: CSIC has sent a new scientific survey ship to the area to map the sea bed. By all accounts, the boat, the Sarmiento de Gamboa, it is the best oceanographic ship that could have been sent.

Update 27 November: It’s been bubbling away like anything today, and the Government has released a picture of one of the “lava bombs” picked up by an incredibly brave coastguard ship. The size is awesome, and the scale can easily be determined by comparison with the legs of the person behind it.

Lava bomb collected November 27. Images courtesy Presidencia del Gobierno de Canarias' photostream
Lava bomb collected November 27. Images courtesy Presidencia del Gobierno de Canarias' photostream

The ship that collected it can be seen in the following video. It is time lapsed, so there is more than an hour compressed into 8 minutes. At first it looks as though we’re watching a tiny area, with coal-sized lumps coming to the surface, but the coastguard ship that comes into view at around 2 minutes into the film shows the real scale: it looks like a children’s show animation in a way, but it is film from the webcam on the coast so is taken from some distance away.

[youtube]http://www.youtube.com/watch?v=XszK0_xt9a8&feature=player_embedded#![/youtube]

Update 26 November: There is renewed staining on the Las Calmas sea, and smoking magma on the surface. Few registered earthquakes in the Frontera-El Golfo region (IGN only lists those over 1.5), but several minor ones, and a couple of them have been quite shallow, at a depth of less than 15km.

Update 25 November 6pm: PEVOLCA has lifted the restriction on everyone who has been evacuated from the Las Puntas area, which was the part of El Hierro that had a 4.6 earthquake recently. La Restinga residents had already been allowed to return home.

The Los Roquillos tunnel has been reopened despite serious concerns in some quarters about its structural safety.The Puerto Naos and Tacorón beaches, and the general south coast remains closed to the public.

Update 25 November: There was a 3.1 earthquake at 2.35 last night (1.35 our time), and the harmonic tremor seems to be building again. It is to be confirmed later, but the bubbling that is being seen again on the surface of the sea does indicate an increased number of vents, and possibly much closer into land than previously.

There is also an apparently marked deformation of the Tanganosoga area, a volcano in the area marked red below, and a deflation in the area marked blue. This does tie in with scientists’ reports of magma seeping through channels underland, raising the possibility, albeit distant, of an eruption on land.

Image: GeoLurking. Inflation hypocenter of Tanganasoga – Discussion HERE

Update 22 November: There seems some confusion now as to whether there is a new vent or not. Yesterday there was said not to be one, but the indications are that there might be one after all. What can be said securely is that there are sudden pulses of volcanic gas coming up 200 metres to the east of the known eruption vent. There is also renewed bubbling and magma being ejected above the sea, and the indications are that there could be several new vents. Also, a 3.3 earthquake was registered at 16.46pm (15.46 our time) in the Frontera-El Golfo area. It was felt by the public.

Update 21 November 10pm: It appears that the new area of bubbling is not a new vent.

There was an earthquake of 3.3 at 6.02 this evening in the Frontera-El Golfo area. Perhaps more significantly, however, there was one of 2.4 at 7.20pm. It sounds far milder, but it was in the south, and underneath land, specifically underneath the coast of Puerto Naos, and at a depth of 15km, quite a bit shallower than most others.

It also occurs to me to say that when I give times, they’re taken from the IGN page, which is the National Geographic Institute. That means they’re mainland times, so always deduct an hour of them for Canarian time.

Update 21 November 1pm: And now a new stain is forming, with signs of bubbling again. This is in a slightly different place, though near the other vents south of La Restinga, and it is thought to be a new eruption vent. The Guard Civil are to carry out a fly-over this afternoon to try to confirm.

Update 21 November: Overnight and this morning, the harmonic tremor is reducing, and the number of earthquakes is reducing. It’s calming down again … for the moment.

Update 20 November: And at 3.15 last night, there was a tremor of 3.7 on the Richter scale, again in the Frontera-El Golfo area. It was felt by the public. The harmonic tremor remains very strong.

Update 19 November: The harmonic tremor graph is varying quite a bit at present, with dips said to present an increased risk of larger earthquakes. The last collapse in the graph the day before yesterday resulted in an increase in intensity and frequency of tremors to a maximum quake of 3.7 yesterday afternoon.

The harmonic tremor started building up again this morning until the graph became almost saturated again around 5.30 this afternoon, and half an hour ago, at 6.27pm, there was a tremor of 3.3 on the Richter scale which was felt by the public.

Update 18 November: Tremors have been increasing in number and intensity throughout the day, the latest being a 3.7 on the Richter scale at 3.32pm in Frontera-El Golfo which was felt by the public.

Update 17 November 11pm: The harmonic tremor readings suddenly reduced noticeably just under an hour ago (at 10.08pm). The last time this happened it heralded stronger earthquakes.

Update 17 November 9pm: ITER scientists say they have detected an extremely significant increase of helium and carbon dioxide in the water just to the south of La Restinga, next to the area where the bubbling has been taking place. The helium readings are, they say, between 4,000 and 35,000 times the normal concentrations.

The readings were taken thanks to logistical support from the science boat “Profesor Ignacio Lozano” and collaboration by the Instituto Canario de Ciencias Marinas (ICCM), the Plataforma Oceánica de Canarias (PLOCAN), and the Instituto Español de Oceanografía (IEO).

Involcan scientists are on board the science boat “Ramón Margalef” to try to see if they register similar readings in waters to the north of El Hierro. Meanwhile, the increases currently being registered in the south are strongest at a depth of some 100m. The Tenerife Cabildo said that they were the result of the depth of the eruption, the magnitude of its volcanic-magma-hydrothermal discharge, and the predominant marine current. I rather take that as “we don’t know why” …

Update 17 November 6pm: Here is a beautiful, if staggering, picture taken today from Involcan and the Guardia Civil fly-over of the activity visible on the surface of the submarine eruption … La Restinga on the coast.

flyover las calmas 17 november

Update 17 November: It was quiet overnight, indeed with very few tremors, but this morning the harmonic tremor graph is saturated: the pressure seems still to be building up.

[vimeo]http://vimeo.com/32196808[/vimeo]

Update 16 November 6pm: The Canarian Volcanic Association (Asociación Volcanológica de Canarias: Avcan) has said that the tremor signal has risen continuously since midday today, when the above video was filmed in a fly-over, and that if this continues, new eruption points would be expected. According to Avcan, the tremor signal rose more in the lower frequencies than the higher, but overall has increased by some 35-45%. This is said to be the third peak of activity, and another earthquake above 4.5 on the Richter scale would not be surprising at some point this evening or overnight. At present, things are quiet but seem to be building up again, with the stain on the surface clearly indicating activity under water.

Update 14 November 7pm: Despite allowing La Restinga residents to return to their homes, Pevolca has also declared El Hierro’s south coast as a no go area for reasons that aren’t clear to me at the moment. I would always have said that La Restinga was on the south coast itself, but I suppose it could be classified as being at the southern tip of the east coast.

Update 14 November: Things have been generally quiet again today, despite the presence of some bubbling and pyroclastic material being ejected and smoking on the surface of the sea. As a result, Pevolca has permitted the Los Roquillos tunnel to reopen during daylight hours. Residents of La Restinga are also to be allowed to return their homes.

Update 13 November: On the surface things have been fairly quiet since Friday’s 4.6 earthquake in the Frontera-El Golfo region, but scientists were saying things were very much ongoing out of sight, with a virtually constant “harmonic tremor”, suggesting magmatic activity at depth.

Throughout yesterday, there was some bubbling in the Las Calmas area, but nothing really to post about, and it was bubbling and then dying away anyway. Today, the bubbling seems to be coming back more strongly, and there is a renewed mark on the water, brown inside with green around the edges, and with foam at the circumference. There is also a strong gas smell being reported.

Update 11 November 3pm: The El Hierro Cabildo, together with Movistar, have now set up an official webcam: the link is HERE. You will see that there are two tabs; one is focused on La Restinga and out to the Las Calmas sea, and the second one more closely looking at the Las Calmas sea eruption zone itself.

Update 11 November 2.30pm: Scientists say they now consider a second erupting volcano more likely. This is in the El Golfo area, which has been experiencing most of the earthquakes, including this morning’s 4.6. The science boat will confirm, of course. There is also a possibility, “not being ruled out”, of a second eruption in the Frontera-El Golfo region on land.

Update 11 November: El Hierro has registered the strongest earthquake so far in the whole eruption, a 4.6 on the Richter scale which was registered at twenty past midnight in the El Golfo area. It was at a depth of 21 km but very close in towards land. One of the Frontera roads is said to have been closed after rockfalls provoked by the tremor. The earthquake was felt throughout the island as a strong shaking, as well as in La Palma and widely throughout south Tenerife.

Update 10 November: The science boat ‘Ramón Margalef’ will move to the El Golfo area next week to try to confirm whether there is another volcano there. The confirmation came from the team of scientists on board the boat, which is presently in harbour in Santa Cruz.

Update 9 November 4.30pm: Two small bays on the south coast not far from La Restinga have been closed because of toxic gas emitted by the Las Calmas volcano. The bays are Tacorón and Puerto Naos, and the gas, carbon monoxide, was sufficient yesterday to cause light poisoning to an IGN technician who was taking samples in the area. The technician is fine and has returned to work today, but the bays have been closed to the public.

The other restrictions in place on El Hierro, such as closed roads and the evacuation of La Restinga (people are allowed there during daylight hours but not to sleep there), remain in place.

The sea has remained calm throughout the day.

Update 9 November: After all yesterday’s activity and anticipation, today is calm, placid. Another lull before another storm, no doubt.

Update 8 November 5.30pm: Just after half past four, a lot of steam was visible coming out of the bubbling area of Las Calmas, and there are apparently 35-metre jets of of ash, magma, gas and pyroclastic material now. There is also a rudimentary cypressoid plume, it seems, which would be expected as an integral part of phase 2 of a Surtseyan eruption, being the effect of a violent interaction between water and magma.

nov 8 flyover las calmas

[youtube]http://www.youtube.com/watch?v=Yg4UZmJE7BQ&feature=player_embedded[/youtube]

Update 8 November 1pm: The Spanish equivalent to the BBC, TVE, says that it is in place on El Hierro with satellite connections in order to provide live coverage of the expected eruption. TV Canarias says that it will interrupt any scheduling and go live to any action. Involcan has released the spectacular picture above, taken during a flight this morning over the Las Calmas area. Below it, I’ve inserted a video from TN1 this morning.

Update 8 November midday: At 11.07am a tremor of 3.5 was registered in the Frontera-El Golfo region, and minutes later a considerable bubbling was seen on the surface of the Las Calmas sea, clear evidence if any was needed, of the connection between these two areas of seismic activity.

Update 8 November: Much activity this morning, with reports of large rocks being shot out of the water with such energy that it is clearly visible from land.

Update 7 November 9pm: Unconfirmed local reports say that there are red lights on the surface of the Las Calmas sea and an almost continuous tremor being felt on the ground.

las calmas water temperature

Update 7 November: The Las Calmas volcano is causing increased bubbles on the surface again, and steam and ash columns are anticipated, perhaps even within the next few hours. Involcan has released the above picture showing the difference in temperature between the bubbling water and the surrounding sea only inches outside the perimeter: the difference is 11º centigrade.

Meanwhile, the Guardia Civil are scrambling to get anyone in the La Restinga area away from the coast urgently. Apparently a “piedra enorme” (huge rock was expelled among the steam and pumice.

Update 6 November: Throughout today, there were tremors of 3.4 in the Frontera-El Golfo area at 9.50 am and 4.30pm, a 3.9 in the same area at 6.25pm, and a 3.1 at 6.51pm. These are just the tremors recorded above 3 on the Richter scale. There have been several others at a lower level.

There has also been a significant increase in CO2 from the new Las Calmas volcano to the south of La Restinga. The increase in CO2 is one of the parameters taken as a precursor to an eruption.

The bubbling on the surface of the sea has died away for the moment, but this is considered to be temporary, and a lull between an underwater eruption and one that we can actually see above the surface of the sea.

Update 5 November 9pm: La Restinga has just been evacuated for a second time, though many locals had already abandoned the village.

The latest evacuation has been called as the bubbling on the surface is now very visible as columns of steam, and at sunset they reached the height of a couple of storeys. Residents, before they were evacuated, stood on the shore and applauded the sight!

If the original “Surtseyan eruption” analysis was correct, we’re in phase 2.

Update 5 November 3.30pm: Pevolca has announced that in addition to closing the Los Roquillos tunnel, it has now:

  • closed the Las Puntas road from the Los Caminos Cruzados cross to el Pozo de los Padrone;
  • closed the Ecomuseo and lizard sanctuary roads;
  • blocked the la Sabinosa road between Sabinosa and Frontera;
  • evacuated houses in the Pozo de las Calcosas area, and closed the access road;
  • closed the section of the Lomo Negro road between the Faro de Orchilla junction and Pozo de La Salud.
  • instituted 24-hour patrols on the La Cumbre route, as well as on the Pozo de la Salud and La Tabla roads.

Last night’s 4.4 earthquake was felt more strongly than the previous 4.4 because it was under land rather than sea. A new “focus”, i.e. volcano, is now expected to develop in the Frontera-El Golfo region, again under the sea as in the case of that to the south of La Restinga.

The public is advised that there is no current risk above that which already existed, and is asked to remain calm.

Update 5 November 10.30am: There have been another three tremors above 3 on the Richter scale this morning between 9 and 10am; the first was at 8.59am and measured 3; the second was six minutes later and was of 3.5; the third was the largest, of 3.9 at 9.44am.

Update 5 November: some 11 families have been evacuated from the Las Puntas area at the north end of the El Golfo region because of rockfalls after last night’s 4.4 earthquake, and the Los Roquillos tunnel is closed again. There was another perceptible tremor around midnight last night. This was in the Frontera region, and was of 3.6 on the Richter scale, and considerably shallower at only 11 km than most others recently.

In addition, scientists have confirmed the “alignment” of the two areas of seismic activity, namely the new volcano south of La Restinga and the area of greatest tremors, Frontera-El Golfo. In other words, this is the same “fracture”. To many this perhaps seems obvious, but it is now officially confirmed by Pevolca, who say that the worst scenario is that the whole fracture goes at the same time and produces eruptions in both regions simultaneously. This was said to be a “remote” scenario, but a possible one. Proteccion Civil is, in any case, gearing up to full emergency, though all evacuations are presently seen as being handled on El Hierro itself.

eruption focal alignment

Update 4 November: A tremor of 4.4 on the Richter scale was registered at 8.36 this evening off the Frontera coast. Those who have experienced these tremors say that this felt the strongest so far, feeling stronger even than the 4.4 on Wednesday evening.

Meanwhile, Pevolca says that the eruption fracture to the south of La Restinga is slowly approaching the coast, as can be seen in the above picture. The tremor was so strong that it was felt in La Gomera, and even in Tenerife, where it was felt in the Santiago del Teide and Arafo areas.

[youtube]http://www.youtube.com/watch?v=OAwkBMOsT20&feature=channel_video_title[/youtube]

Update 3 November: There are bubbles again on the surface of the sea above the new volcano to the south of La Restinga. The phenomenon that can clearly be seen from the village itself, where a fair few residents have decided to pre-empt any further evictions and have left the village and their properties to their fate. Others have gathered at the shore and have been shouting in frustration at the volcano to show itself. Meanwhile, scientists continue their analyses, and Protección Civil authorities are gearing up for an emergency.

There are some lovely images of El Hierro in the above video, with the mark in the sea clearly visible from 52 seconds, and at 1.02 one can see the renewed bubbling from the volcano, and how close it is to La Restinga.

Update 2 November 7pm: A tremor of 4.4 on the Richter scale has been registered at 6.10pm this evening on the coast of Frontera, the largest so far. This follows this morning’s 4.3.

Update 2 November 6pm: This morning’s grade 4 tremor is now formally classified as a 4.3.

Meanwhile, the team of geologists from the University of Barcelona who have been analyzing the material, said that the magma expelled by the new volcano is of the most explosive type. The team has warned of the danger associated with such eruptions, and the risk of underestimating the volcano.

The team confirms that the magma is of volcanic origin even though final tests still have to be carried out to achieve a full detailed analysis. What can be said is that the white material is of a “rhyolite” type, an igneous volcanic rock of far higher explosivity than basalt.

Update 2 November 3pm: Just as an update on the “smoking magma analysis”, scientists are saying that they’ve never seen anything like this before, and are not able to classify it from previous experience.

They are still analyzing its components, and say it is a white spongy mass covered with a dark glassy material which they presume to be some sort of basalt composition comprising minerals of peridot, pyroxene, magnetite and halite (sodium chloride). This part is not surprising, but the white interior is, since it is minerologically very different, and might even have been brought up from the oceanic crust. They think it’s a type of silica, and it will be some days before they can say more clearly.

Update 2 November 1.30pm: The results of the analysis of the smoking magma I posted about on 31 October are not comforting. Rather than suggesting a Surtseyan type eruption, which is what they’ve been predicting for some time now, the “mingling” of different elements is said to “increase explosivity”, and suggests a “potencial explosivo mayor”, a “great explosive potential” which is a trigger for a great eruption. Put together with today’s carbon dioxide readings, the new volcano would seem to be coming to life again with a vengeance. And of course, this is all separate to the tremors, inreasing in number and intensity, in the western El Golfo region. HERE is a link to a report on the magma analysis.

Update 2 November 1pm: The Instituto Vulcanológico de Canarias (Involcan) has confirmed a significant increase in carbon dioxide being released into the atmosphere from the new volcano to the south of La Restinga. The emission is registering the highest values since the eruptive process began. Pevolca, which is the “Plan Especial de Protección Civil y Atención de Emergencias por Riesgo Volcánico” says that the emission of CO2 is one of a set of indicators for a volcanic eruption.

Update 2 November: A tremor of 4 on the Richter scale was registered in Frontera at 7.54 this morning, one of around 40 or so in the same area since midnight. The tremors in this area continue to increase in number and intensity, though as yet, Pevolca has kept the area on yellow alert. It is only La Restinga that is on red alert at present.

Pevolca, meanwhile, is organizing equipment and supplies for an evacuation camp on the island in case of what looks like an increasingly likely eruption in the El Golfo-Frontera region.

[youtube]http://www.youtube.com/watch?v=zGKHmAvQrNo&feature[/youtube]Update 1 November: There have been four tremors over 3 on the Richter scale since 10pm last night. IGN registered a tremor of 3.9 on the Richter scale at 10.06pm, followed by another of 3.9 at 4.15am, one of 3.3 just after midday, and the fourth, again of 3.3, at 16.08pm. These four were all clearly felt by the public in the Frontera municipality, and are just the four largest of some seventy today, all in the sea to the west and northwest of the Frontera area.

Director general de Seguridad y Emergencias del Gobierno de Canarias, Juan Santana, said that the situation could settle down again, or another fracture could open up, this time in the sea off El Golfo with a second eruption as happened south of La Restinga. The present eruption to the south of La Restinga continues, and the above video is the first sight of actual images of the environment of the new volcano there. The film was taken by robot craft from the science ship.

The public has been asked to remain calm and to be alert to developments.

Update 31 October: And now the La Restinga eruption has come back to visible life today with an increase in seismic activity, and the appearance again of smoking magma on the surface of the sea, leaving a darker and denser mark than in previous days.

The science boat Ramón Margalef has collected samples, which appear to be different to the initial eruption. Now, as opposed to sulfur, it seems to be a type of pyroclastic lapilli, effectively volcanic ash of the size of small stones, of a reddish colour. This material still has to be analysed by the scientists.

Eventos_HIERRO_10 (490 x 490)

Update 30 October: El Hierro has had two tremors today registering 3.9 on the Richter scale, both in the sea to the northwest of Frontera. The first occurred at 7.46 this morning, and the second at 1.05 this afternoon. A third tremor of 3.2 was also widely felt. These are just the largest three of many, a seismic activity off the Frontera coast that is said to be increasing in intensity and frequency. The above picture shows the last 10 days, and demonstrates how the seismic focus has shifted from the south off La Restinga to the north west and the El Golfo area.

[youtube]http://www.youtube.com/watch?v=sj8JTJP7gNM[/youtube]

Update 27 October: The Canarian Government’s Director de Seguridad y Emergencia, Juan Santana, has announced today that the Los Roquillos tunnel will now reopen fully, and that the evacuated residents of La Restinga can return to their homes. The situation will continue to be monitored, however, and there is still a complete ban on bathing and fishing in the sea in the area.

Meanwhile, as promised yesterday, the science ship has constructed a digital image of the volcano. The resulting video is above.

Update October 26 11pm: A press conference given by scientists from CSIC, IEO (Spanish Oceanographic Institute) and Pevolca, has said that soundings from the science boat Ramón Margalef show that El Hierro continues to be volcanically active.

They do not believe that the current shift of seismic focus to Frontera is related to an emission of magma, but intend to continue to monitor the situation there to determine if the activity is the prelude to a new eruption, not least because it was there, in the northern zone, that the whole series of seismic activity began.

The scientists consider that what they are currently seeing is quite clear evidence of magma and ongoing seismic activity some 20 to 25 kilometres below El Hierro. Analysis of all the data available to date suggests, however, that any eruption has only a low probability of taking place place on land.

At sea, however, the eruption to the south of La Restinga is continuing, as evidenced by thermic indicators and gases, as well as seismic signals which have never stopped and are practically constant. The boat will try to capture images tomorrow despite the difficulties created by the volcanic material in the sea.

In the new volcano, imaged yesterday, a rising current has been detected of a significant gaseous column which has reached the surface of the sea.

This first phase of the ship’s work has been to identify the sea bed electro-acoustically. Tomorrow, this work will be complemented by digital images and the taking of samples.

Eventos_HIERRO_2011 (400 x 400)

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