Posted on by Jón Frímann

Increased eruption activity in El Hierro volcano

I was going to post this yesterday. But I fell a sleep at 17:00 UTC and I didn’t wake up until 03:00 UTC.
*******

The eruption in El Hierro volcano continues as it has been doing for past few weeks with little change. The first eruption vent that did open south of El Hierro Island has continued to erupt. But so far no Island has formed and it is unclear if it is going to form, as the depth is great in this area. Since yesterday around 06:00 UTC the harmonic tremor has been increasing. But this suggests that new vents have opened up in the south eruption area. I got some pictures of that yesterday in the email. But they did not show anything new in my view. Thanks to the readers how did send me those pictures.

The current fluctuation in the harmonic tremor from El Hierro suggests that magma is on the move in the north part of El Hierro Island. Both off the coast and maybe inland on the Island where earthquakes have been taking place. It is impossible to know how this is going to develop during the next few hours to days. As that depends on the rock structure of El Hierro Island and earlier eruptions.

Earthquake activity

During the past two weeks the earthquake activity have been growing in the North-west part of El Hierro Island. The reason why this is happening is that a new fissure is about to open in this area. As I have mentioned before in earlier blog posts. When and where is impossible to know for sure. The largest earthquake so far took place this morning, it size was ML4.0 with the depth of 20 km. But this is the automatic data from IGN. This pattern of earthquake activity is most likely going to continue during this eruption process in El Hierro volcano. Since the eruption type here is a fissure eruption.

It is worth noting that earthquakes in once place does not mean that the eruption is going to happen in that place. As the magma can travel in dikes all over the El Hierro Island and show it self anywhere on the Island it self. So the general risk is high in my opinion. The only action that can be taken is to be prepared for sudden eruption of new vents on El Hierro Island. Since there is a good amount of magma on the move inside El Hierro volcano.


The harmonic tremor in El Hierro at 08:54 UTC (when picture is saved). The spikes are earthquakes, and harmonic tremor spikes are the “waves” in the harmonic tremor pattern. Copyright of this picture belongs to Instituto Geográfico Nacional.

Update 1:

* When I wrote this blog post. This two earthquakes took place.

1109584 02/11/2011 08:37:11 27.9267 -18.1084 3 1.7 mbLg NW FRONTERA.IHI
1109582 02/11/2011 08:36:00 27.5986 -17.9594 1 1.9 mbLg S EL PINAR.IHI

This are the most shallow earthquakes that I have seen so far. From the depth it is possible a magma has found a clean path to surface in this two areas. Sadly there is no map. So I am not sure where this earthquakes took place in El Hierro volcano.

Update 1b: The earthquake have been revised. Now the depth is 9 km for the ML1.7 and 22km for the ML1.9.

The shallow earthquake.

1109584 02/11/2011 08:37:11 27.9304 -18.1107 9 1.7 mbLg NW FRONTERA.IHI [+]

I am going to post more information when I know more on what is taking place in El Hierro.

Blog post updated at 11:24 UTC on 2 November, 2011

1,078 Replies to “Increased eruption activity in El Hierro volcano”

  2. Time for a new thread Jon, its getting Waaaaaaay too long to keep up with. 1052 hits on this one.

  3. Translation of the El Hierro Daily which is the Daily Iron in translations.

    CRISIS SPECIAL SEISMIC – 11/04/2011 (11:50 pm)

    The submarine volcano has returned to La Restinga this morning bringing smoking pyroclastics to the sea surface, (pumice?) as confirmed by the El Hierro Daily. (Thats the Daily Iron folks)

    Many of the readers who have contacted this newspaper reported that plumes observed on the sea contained pyroclastic products of the material.

    For its part, the scientific committee spokesman Protection Plan Civil Volcanic Risk (Pevolca), Carmen Lopez, said yesterday that the seismic events, which have intensified in
    last days, are the scene of undersea eruption at La Restingas, which began on 10 October.

    Lopez noted that the high seismicity that has occurred with magnitudes of 4.3 and 4.4. has affected the magmatic feedback mechanism eruptive process of La Restinga, “generating a process of a pressure injection in the magma that increases the rate emissions and releases large amount of gas. ”

    This phenomenon is what has been represented in pulses, continuous harmonic tremor and new spots appearing on the the sea surface when calm, which turns it white, mixing with the brown pyroclastic material, because of the presence of the gases.

    Interesting… anyone got any pictures yet?

  4. P.G. – Experts in volcanology from LAPROVINCIA.ES moved to the island of El Hierro yesterday have concluded Friday that have been a proliferation of sources of emission of gases in magma and eruptive process underway under La Calmas in the area of La Restinga, so now there would be three sources of emissions in the same area of the eruption.

    Throughout the morning the bubbling in the maritime area has increased, to become a “sight”, according to the inhabitants of La Restinga.

    The images taken by the scientists of National Geographic Institute (IGN) in a flyby of Emergency and Rescue Groups Canary Islands Government (GES), has shown the alignment of the emission points of the underwater eruption to along the fracture.

    (Anyone seen the alignment pictures?)

    The Specific Plan Committee Civil Protection Risk Volcanic Islands (Pevolca) will inform the public of their findings at 18.00 hours this afternoon.

    Seismicity-IGN has confirmed to the Director of the Civil Protection Plan for Volcanic Risk (PEVOLCA) there has been a considerable decrease of the seismicity during the day yesterday.

    Thus, during November 3, 2011, 39 earthquakes were located, one of which was felt by the population of El Hierro. The largest of the movements was of magnitude 3.2 on the Richter scale at 18:10 pm (UTC) and was at a maximum intensity of III (EMS) in the town of Frontera. This event was located on the coast in the area of El Golfo, 15 kilometers deep.

    The rest of the recorded earthquakes were located in the same area, aligned NNW SSE from the sea to the center of the island forming two distinct groups, the first among the 14-15 km and the second between 20-23 km.

    1. Thanks, awesome view!

      Now I just wish for the people who mount the cameras to tie them down properly, so they don’t sway in the wind as they do know …

  7. Carl le Strange says: November 4, 2011 at 09:56

    ======
    ….if it was not that pesky down-shift in frequency. Because that would pretty much give the logical conclusion that Bobs pipe is a Kazoo (or perhaps the trombone would be a better example). To have downshift you would need to elongate the organ pipe in mid-tone
    ======

    Actually you have it backwards (sorry). Liquids have a faster speed of sound (~1500m/s) than a gas (~300m/s). So a tube 1km long, filled with lava will have a transit time of about 0.67 sec, and a basic frequency of about 1.5 Hz. The same tube filled with a gas at 300m/sec it will take 3.3sec so the SAME 1km pipe will have a frequency of 0.3 Hz whereas before it was 1.5Hz. So you get precisely the effect seen of a high initial note (lava) that declines to a lower one (lava+gas).

    1. I didn’t get the Kazoo backwards.

      But Oz, you know, my friend, hell I think you nailed it 🙂
      It really sounds plausible.
      I should have thought of that, hork hork (hitting myself over the head) 🙂

    1. There are 16 photos in this album, browse them on the bottom right. Some are amazing.

      1. The current confuses interpretation. Some rows of circular colouration look like they age away from the origin. Video would be much more informative.

  9. Very Important Update 04/11 – 13:37 UTC :
    Joke Volta reports from La Restinga :
    – we just went from El Pinar to La Restinga
    – a very sulfurous ‘rotten egg’ odor was noticed on parts of the road
    – the viewpoint towards the Las Calmas sea is showing multiple Jacuzzi spots close to the island
    – Joke took some pictures, but she is not sure whether it can be see on the pictures (she works with a cheap camera)
    – she is now heading back to El Pinar and will send the images shortly
    – it is clear to earthquake-report.com that, as Raymond told us yesterday night, we have entered a new phase in the El Hierro volcano activity

  12. I think they have adjusted the gain again on CHIE or did something else happen – no corresponding drop in intensity on the other sites tho’.

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