Posted on by Jón Frímann

Special report: Update 4 on the eruption in El Hierro, Canary Islands, Spain

Short note on comments: During the eruption in El Hierro there has been a lot of comments on this blog. Over the past 4 days (or so) there have been about ~1500 comments. If your comments is held for moderation, the blog says so. Do not try to repost your comment if that is the case. As the second comment is just going to be held in moderation as the earlier one. It takes me a little while to approve the comment and to make it appear. If your comments disappears and cannot be seen, the spam filter has eaten it. It also takes me a while to check the spam filter and restore comments that have gone there. Please do not just post comment with nothing but links, that increases the risk that the comment is going to be eaten by the spam filter.
*****

Short note: Please note that I am not a expert in the field of volcanism, volcanoes and earthquakes. I never claim to be one. Regardless if I am asked or not. I am a man with interest in this field. I read a lot of books and studies on volcanoes and earthquakes. But that does not make me a expert in this field. If you want to speak with a expert, go and find one. Because I am not it.

Now. About the eruption in El Hierro volcano in Canary Islands. This is going to be a short blog post about the eruption.

From what I can tell and the information that I have seen. At least two more vents have opened up on the from what I can gather on the pictures and the reports from Canary Islands. So far all the new vents are under the ocean and at depth of no less then 150 meters. So seeing them directly is quite hard for the moment. There are continues deep earthquakes under El Hierro volcano, but that suggests that new magma is flowing into El Hierro volcano.

During the weekend floating magma bombs where (or some type of magma, I do not have the exact word for it in English at the moment) floating on the ocean. But this means that at least one of the vents that started erupting in the beginning is getting close to break the surface of the ocean. If the eruption continues in that vent for a little while longer. If it gets above the surface of the ocean, it is going to form a island and a lava eruption is going to start once the ocean cannot get any more into the crater.


The harmonic tremor of the eruption in El Hierro volcano today (16 October, 2011) at 22:35 UTC. Copyright of this picture belongs to Instituto Geográfico Nacional.

There is a risk of new fissures in El Hierro opening up without warning. From what I am estimating, the area that this can happen has expanded about ~5 km or so from my original estimate that I made in few blog posts ago. The risk of new fissure opening up on land is going to remain high while this eruption is taking place. But this might well be a period of eruption activity for El Hierro. It is impossible to know for how long it is going to last, it could be weeks or it could be months and up to years of activity.

I am going to post more information on El Hierro when I know more tomorrow. I am also going to write about the earthquake activity in Hengill volcano tomorrow if I have time to do so.

230 Replies to “Special report: Update 4 on the eruption in El Hierro, Canary Islands, Spain”

  1. That is really interesting. We might be heading into a second phase of surtseyan activity, but that is just speculation. I personally dont think that a new vent opened, i believe a big explosion caused the spike at 19:57, but thats just my opinion. Still very speculative at the moment.

    1. Would a geysir like eruption cause a big explosion do you know? Things seem to be moving along very nicely.

      2. a phreatomagmatic explosion which i expect happens when the magma gets very close to the surface where the pressure of the water is very low, so that the magma is able to react with the water and the air.

  4. Update 17/10 – 21:30 UTC : – During a PEVOLCA meeting this evening was decided that a decision for the return of the people to La Restinga has been postponed to 4:00 PM (16:00) tomorrow, due to the very strong sulfurous odor which is blowing today in the La Restinga direction. The inhabitants of La Restinga have been invited tomorrow at 4 PM in the cultural center of El Pinar to receive the decision directly from Mr. Santana, the person in charge of the safety measures.
    http://earthquake-report.com/2011/09/25/el-hierro-canary-islands-spain-volcanic-risk-alert-increased-to-yellow/
    I am so glad they have postponed the decision to let people return. It doesn’t seem very safe to me, but then I don’t know much about it. Just prefer caution when peoples safety could be at stake, although it must be awful for the people evacuated.

    1. Just heard those news, but they postponed the evacuation, not because of the danger of an eruption closer to the coast, but “because the currents are bringing gases and volcanic material nearer to the coast”.
      So, they say they are sending a boat to take measures of gas contents and check if it is safe to have people coming back.
      I sense a smell of “rotten eggs” in those news…

    1. Thank you. All stations in El Hierrro are showing some shift: VALV has moved to the SW; FRON has moved to the SW; REST moved NW then SW; SABI moved SE; and, PINA moved SW.

      Interesting that they are also recording some shift, albeit a lot less, in Tenerife: ITER did a little wobble to the west & back; and IZAN also shows a small wobble.

      Hope I understood the plots & got the directions right.

    1. Armand I would love to know too. Does look very odd on the spectrogram – definite increase in the higher frequencies, happened quite suddenly and not gone back to “normal” (of that is what you can call the trace beforehand – seems ages since it was flat line).

  7. I am not a geologist, neither a volcanologist, but I think I have an idea.

    As a propeller turns in water the friction of the spinning blade heats the water around it to a supercritical stage and they explode as bubbles of steam. This process is called cavitation.
    The relevance to what we are noticing here is that the cavitation of a large propeller is at a close point of origin more felt as a deep reverberation, than heard as a noise. The reverberations main components are normally found around the span between 4 – 8 Hz.
    I think that the build up of the new Island (EldfjallþessierþekktursemBob) has reached a stage where steam bubbles can form, and then collaps. I think what we are noticing right now are the formation of steam explosions. Or in other words, the formation of a Surtseyan phase 2 eruption.

    1. I do not know.
      I could buy that the storm could cause today spike, but what I am having a problem with is…

      That Grimsfjöll GPS has fallen 50mm in just a few days…

      1. Maybe trying to get in shape in order to compensate the Thanksgiving Turkey…ehm…back2topic…

        Don’t think that this was the wind. Iceland had stronger winds during the last days.

  12. Yes, harmonic tremors decreased the last 12 hours. In addition to that the gas bubbles on the surface have disappeared.

  13. At ER we are in search of a vulcanologist or somebody with a lot of experience in following all types of volcanoes.
    As i like this blog even more than mine it is an absolute necessity to regularly link from ours to Jonfr.com (like i did a couple of times the last couple of days).
    His/her task : giving a few lines of comment on what we see on seismographs, frequencies, depths etc.
    @ ER we have a totally different public than at jonfr.com, so there is in no sense a competition going on. At the contrary, i hope more devoted volcano followers will find this great blog. You can reach me at quakesos@hotmail.com

Comments are closed.