[breaking] Vulkaanuitbarsting bij Canarische Eilanden

2.6 nog half uurtje terug.

While everything is quiet in Iceland. I am going to continue my coverage of the eruption in El Hierro volcano. Information in English also seems to be lacking for some reason. Please note that I have little understanding of Spanish, so I am just using the data that is available to me on the internet to figure out what is going on.

First I want to say that I am not a expert. I never claim to be one. My knowledge of volcanoes and earthquakes are the result of hard work and studying them on my own (reading research papers and other sources).

It is bit unclear what is going on in El Hierro. But from what I can tell least two things have happened during the past 24 hours. The first thing is that a eruption started at ocean floor around 04:18 UTC yesterday (10 October, 2011). This eruption appears to have been small and was not noticed on the surface of the ocean. Around 06:10 UTC this morning (11 October, 2011) a large movement of magma started to take place inside El Hierro volcano. Where exact break up of this magma is going to take place is unclear at the moment. But it is clear that a eruption is taking place and it is more chance then less that magma is going to find it self a new pathway up to the surface soon. As I do not think that the current eruption vent is keeping up with the current magma that is under El Hierro. But it is worth to notice that El Hierro does not seem to have a magma chamber, like Eyjafjallajökull volcano in Iceland so the eruption size is terminated by the current inflow of magma.


The harmonic tremor as it was on 10 October


The harmonic tremor as it was on 11 October, 2011 at 20:29 UTC

As clearly can be seen it has grown by a margin or more (I can’t tell for sure) in the last few hours.

What is however really interesting is how this eruption is changing fast and without any warning at all. But this is however something that might be expected from a volcano like El Hierro. I see in the news that they are expecting earthquake activity before new vents or fissures open up. That is wrong assessment in my opinion. As new eruption vents and fissures can open without any or much earthquakes activity at all. Earthquake activity before a fissure vents open up depends only on the rock that the magma has to break trough. In many cases it does not have to create any earthquakes before a eruption starts. Good example of this is the eruption in Heimaey Island in the year 1973. Only a small earthquake swarm was detected before a eruption started. All I personally except before a eruption in a new place on El Hierro volcano is a minor earthquake activity. It is also hard to know if that earthquake activity can be detected based on the amount of harmonic tremor taking place at the moment.

Here is my personal assessment on where eruption might take place in El Hierro. Please note that it might be completely wrong. But I base my assessment on the data out there, that assessment might be wrong.



The most chance of the eruption in El Hierro in my personal opinion marked by the two red circles. Copyright of this picture belongs (original) to Instituto Geográfico Nacional.

There have been some deep earthquakes in El Hierro volcano over the past few hours. This deep earthquakes mean that new magma is flowing under El Hierro volcano. This means that the flow is steady (pressure pulse in the magma creates the earthquakes). So this eruption is far from being over it seems. How long it is going to last is a good question that currently nobody has a answer to at the moment.

Bron

[ Bericht 4% gewijzigd door Frutsel op 12-10-2011 13:33:56 ]

quote:

El Hierro tsunami chance
The Canary Islands Directorate for Civil Protection and Emergency Response yesterday raised the state of alert for seismic and volcanic activity on the Island of El Hierro to red.

The CEO of the agency explained that the increased state of alert only applied to the municipality of La Restinga and the rest of the island remains of yellow alert.

La Restinga (547 inhabitants) is a Town on the southernmost coast of the island, and is closest to the underwater eruption which occurred yesterday, 5 kilometers from the coast and at an estimated depth of 1000mts.

The CEO also stressed that this was purely a precautionary measure and that there was no immediate threat of danger, however there is a strong likelihood of a further eruption over the next few days.

Experts from the National Geological Survey and the Higher Council for Scientific Research (CSIC) moved to the island have not ruled out the possibility that any such eruption, together with increased levels of magma rising to the surface could result in a new Volcano being created on the island.

The volcanic activity has attracted much interest from around the world - especially in the USA. It has long been speculated that any volcanic eruption of the Caldera de Taburiente Volcano on the neighbouring island of La Palma may cause a Tsunami of up to 300mts that would cross the Atlantic in a matter of hours. Geologists believe that this is exactly what happened when the El Hierro Volcano broke apart and fell into the Ocean thousands of years ago, creating the 'Val del Golfo' crescents shaped bay, and creating a Tsunami that was largely responsible for the creation of the Florida Everglades.

Chatter on the various social networks and forums critcises the United States Geological Survey (USGS) for their lack of communication surrounding the situation in the Canaries. Sources claim that this is so not to panic the public unnecessarily.

Zon vaart zal het vast niet lopen

handige update site - engelstalig

http://www.canariesnews.c(...)o-earthquakes-update

quote:

13/10/2011 @ 09:01 – A new earthquake has been detected, this time to the north-east of the island. Until now, all the earthquakes have been located to the south coast. It took place at 05:10:36 (local time) and registered 1.7 on the Richter scale.

quote:

El Hierro update 2
The eruption in El Hierro volcano continues today, as it did yesterday. But the strength of the eruption appears to have dropped today from what it was yesterday. But this does not mean that the eruption is over. It just means that the current fissure that is erupting is about to close up, mostly due to the material that it has been ejecting into the ocean floor. That means a new fissure or vents is about to open up somewhere. When and where is impossible to know. But this is the nature of volcanoes that erupt in this manner, but El Hierro is a shield volcano [second link here]. Good examples are Krafla volcano and Vestmannaeyjar Island volcano. Both of those volcanoes are in Iceland.

Today around 14:20 UTC there was a sharp tremor drop in El Hierro. This means that the magma flow dropped in the current eruption fissure. This also means that if the pressure is not enough that fissure is going to stop erupting. Because of this has happened a new fissure or a vent should be expect at any time as I have told before. When and where that might happen is impossible to know, as that outcome depends on where the magma finds its pathways inside the volcano. There might not be any earthquakes before this happens, as the rock is unlikey to be hard enough to make them. Some small earthquakes might happen if the rock layer is hard enough. Today few deep earthquakes have been recorded. This means that new magma is getting into El Hierro volcano from the mantle (where no earthquakes happen). This also means that this eruption might take place for some time now. But it is impossible to know for how long, as there might be a lot of magma flowing up from the mantle it self and up to El Hierro volcano.

Many people have been wondering why this eruption has not been seen. The fact is that depth drops quiet fast around El Hierro Island. Around 4 km out the depth is close to 1.5 to 2 km, it is only close to the island that the depth starts to get shallower. At the moment is is hard to say what happens next in this eruption on El Hierro. But more vents should be expect to open up then have already have.

[ Bericht 9% gewijzigd door Frutsel op 13-10-2011 12:13:03 ]

Duidelijke plekken in het water te zien waar de recente uitbarstingen zijn geweest.