El Hierro Volcano eruption (Canary Islands) : Part 18 – December 8 until December 11

This is Part 18 of the El Hierro Volcano eruption report


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With the collaboration of Joke Volta, an El Hierro resident
“Volcano Only” twitter : @VolcanoReport  -  3 in 1  WEBCAM pageEl Hierro Picasa Web Album

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)
Read also: Part 16 (from November 28 until December 2)
Read also: Part 17 (from December 3 until December 7)
Read also: Part 18 (from December 8 until December 11)
Read also: Part 19 (from December 12 until December 15

 Update 11/12 -23:55 UTC
Nothing special to report. NO earthquakes and the eruption has continued at the same pace for the last few days. Harmonic tremor with very strong bursts goes on.

Update 11/12 -18:24 UTC
Yesterday we wrote in our 22:04 update : "Some think the eruption would stop if the earthquakes ceased".
Dr. Boris Behncke from the INGV-Osservatorio Etneo, Catania commented on this statement as follows :

As a matter of fact, most eruptions are preceded by earthquakes, but in most cases the earthquakes stop once the eruption has reached a stable regime. The stopping of earthquakes does not mean that the eruption will stop anytime soon, the eruption might continue for years after the end of significant earthquake activity. Earthquakes are indicative of breaking rocks, caused by magma pushing into areas where there is no established conduit.
Once a stable magma flow occurs through a well-established conduit, there will be no longer any earthquakes.
The cessation of earthquakes only means that the situation has somehow stabilized, not that magma is ceasing to flow.
The real indicator of continued magma flow is volcanic tremor.
Only once the volcanic tremor disappears, then one might reasonably argue that the eruption is over.

Update 10/12 -17:07 UTC
- The jacuzzi has been active to very active all day long. The harmonic tremor graph is showing that the eruption is continuing at a steady pace and accordingly that the vent is growing.
- If the process continues at the current level, we expect that in the coming weeks or even days, the steam bubbles will reach the air and if the vent remains open, the steam will gradually go higher.
- Currently bursts lasting 2 to 4 minutes are occurring every 8 minutes (see picture below for the current time frame).

Harmonic graph image from 16:00 until 16:38 - Image courtesy IGN

Update 11/12 -13:47 UTC
- Pevolca is generallyly far too late with its comments if important phenomena are occurring. The current very strong pulses / bursts of harmonic tremor need an official explanation. The most recent bulletin we find in the IGN site describes the situation on December 9 ! and in very general terms.
- Our opinion : as the eruption is still continuing, the water column on the growing vent is decreasing every hour and every day and the hydromagmatic bursts are occurring faster and faster (see IGN graph). Pevolca might consider telling the people what will happen next.

Update 11/12 -10:16 UTC
- 1 M 1.9 earthquake at 02:11 with epicenter in the El Golfo bay
- VERY active harmonic tremor bursts continuing with less time between each burst.

Early morning stain and turbulence area - Image courtesy Joke Volta

Jose Luis Barrera Morate blog
On December 10th, the submarine volcano La Restinga marked 60 days of uninterrupted eruption. This puts it eighth in duration for all the Canary Islands' recorded eruptions (see table). Multiple fissure eruptions have been treated as a single eruption (for example, the Siete Fuentes-Fasnia-Arafo fissure eruption). At La Restinga, bathymetric data indicate the existence of three vents, some of which are only 150-160 meters deep. Which one is the most active, if several are? This is not well understood. The fact that for 48 hours the tremor has shown more explosive episodes in a nearly periodic manner may indicate hydromagmatic bursts, implying that the active crater is shallower than in the first eruption. (thanks to Denise for the translation)

Update 10/12 -22:14 UTC
Today's Guardia Civil Helicopters / Involcan flight still shows a very active stain and a very special circular jacuzzi without pumice at the middle. Involcan has not given any additional comment on the data they have obtained during this flight (gas analysis and water temperature).

Update 10/12 - 22:04 UTC
NO earthquakes but the powerful (probably hydromagmatic) bursts are more frequent than ever before. Some think the eruption would stop if the earthquakes ceased, which would then happen soon. Our own expectations are written below (green highlighted).

Update 10/12 - 17:48 UTC
Still NO earthquakes but the volcano is still erupting.
Below a collection of today's hourly harmonic tremor graphs (see below for more information) - For all the hourly graphs from 00:00 until 18:00 in full size, please click the individual image.

Click on a small image for the graph of the entire day (00:00 until 18:00) - image courtesy IGN

Update 10/12 - 16:10 UTC
- Readers following the IGN harmonic tremor graphs should know that IGN is rescaling regularly as the burst peaks are reaching the limits of the scale.
- 30 motorcyclists arrived today at La Restinga in support of the local economy.
- The Tourist board of La Restinga has decreased the hotel rates hoping to attract more tourists in the coming weeks
- Airlines serving El Hierro have also reduced the flight rates to El Hierro by request of the El Hierro authorities. They agreed as a gesture to support the hard hit economy of El Hierro.

Update 15:29 UTC - December 10 Joke Volta images
Joke was very active from early this morning on taking pictures of the port, the reef and the coast. When she sends us new ones this afternoon, we will add them to this Picasa video sequence. If you want to see the images Full Size, please click on one of the pictures.

Update 10/12 - 09:24 UTC
- NO earthquakes so far today.
- Medium harmonic tremor with a lot of powerful bursts.
- Very bad weather at the Las Calmas sea and La Restinga this morning.
- Due to the white topped waves one can hardly see any jacuzzi activity or stain, but the stain is clearly present as well as a weak jacuzzi - NO SLS (SLS = smoking lava stones).
- Why are we always talking about bursts ? People who are only looking at the daily harmonic tremor graph will only see vertical extended lines in the graph (upper graph). These vertical lines are sometimes events that last many minutes. The lower graph shows the hourly graph tremor between 08:00 and 09:00 this morning (gray area from the upper graph). The lower graph shows regular bursts lasting many minutes.

Click on the image to watch it in full size - Graph courtesy IGN (Instituto Geográfico National)


Update 09 - 10/12
Diario de Avisos had an interview with Alpidio Armas, the president of El Hierro. One of the most important quotes from Mr. Armas  was that the volcano grew 80 meters in the last couple of weeks. The change in depth was measured by the oceanographic ship Ramon Margalef. The first bathymetry took place on October 24 (2 weeks after the start of the eruption) and the last one last week. Mr. Armas also said that according to the data of the Ramon Margelef 3 vents are active intermittently.

What to expect next ?
Based on Mr. Armas interview and taking into account a number of uncertainties, Earthquake-Report.com expects that :

- if the eruption continues at the present rate and in the same vent, it will take a maximum of 2 weeks to arrive at a depth less than 100 meters. We then would expect very strong Jacuzzis during the hydromagmatic bursts.
- if the same process continues for about 3 to 4 weeks and in the same vent we would expect regular hydrovolcanic explosions during the bursts.
- if the same process goes on 5 to 6 weeks the eruption may become Surtseyan. This is the most spectacular phase of the eruption. During this phase of the eruption ash and steam clouds can reach hundreds of meters to several km in height. Particular to Surtseyan eruptions are the thick,dark-pointed cypressoidal bursts of fragments, often accompanied by lava bombs, shot from the vent.
- if the same process goes on 7 to 8 weeks and in the same vent, the eruption will at least have created a new island.
- the main vent is at a safe distance from La Restinga, so we do not anticipate any immediate danger to the population. 90% of the time the wind blows from the north or north east at this time of year, and accordingly the eventual ash will be blown further into the Las Calmas sea, avoiding damage at La Restinga.
- If a new island forms, it may indicate several months of uncertainty for the La Restinga population as no one knows how long the eruption will last and when it will finally stop for an extended time as there may be several new eruptive periods.
Our expectation is based on medium harmonic tremor such as we have seen the last couple of days. In case of strong or very strong harmonic tremor the time to arrive at these different phases could well be a lot shorter.

If our expectations come true, the eruption will make El Hierro appear on every news show in the world. The island will start to attract visitors from all over the world.

El Hierro Images from Henar Bravo and Joke Volta

Data Update 09/12 - 23:59 UTC
- 2 earthquakes today, 1 with epicenter in the El Golfo bay and the other between Los Llanillos and Tigaday.
- Medium harmonic tremor with irregular bursts keeping the eruption in the Las Calmas sea ongoing.
- The jacuzzi activity in the Las Calmas sea during the day while we only had moderate harmonic tremor indicates that the vent is getting closer to the surface.

Update 09/12 - 16:17 UTC
- Not a lot to report today, but the (weak) jacuzzi area can be clearly seen at this moment. Joke has just reported that a beautiful green stain has been created today.

Update 09/12 - 11:43 UTC
- On the RTVC webcam we have seen a number of Fisherman returning their boats (through the small newly-opened corridor in the sea) from La Estaca to the port of La Restinga.  During the evacuation the fisherman had been instructed to move their boats to La Estaca.

Update 09/12 - 09:18 UTC
- Continuing Jacuzzi action this morning
- Medium harmonic tremor
- 1 M 2.0 earthquake with epicenter n the El Golfo area at 03:00

Update 08/12 - 23:55 UTC
- Screenshots from Juan del Castillo Vivero and images from Joke Volta (stain and surroundings)

Click on the images to enlarge.

Update 08/12 - 21:09 UTC
- Only 1 earthquake today (just after midnight) but the eruption is gradually picking up again. Before the collapse at 04:24 the harmonic tremor was extremely strong. The graph below shows the relation of the tremor after midnight to the current harmonic tremor.

Harmonic graph December 8, 2011 - image courtesy IGN

Update 08/12 - 16:31 UTC
- The new IEO oceanographic ship "Cornide de Saavedra" is navigating close to the stain and even on the stain. This is the 4th research vessel from Spanish organizations like IEO and CSIC to conduct work on the El Hierro eruption.

Update 08/12 - 15:42 UTC
- 1 minute video recorded from the RTVC webcam at La Restinga, El Hierro by Julio del Castillo Vivero.
Smoking lava seen this morning (11.11am) at La Restinga, El Hierro after changing patterns in the volcanic activity characterized last night. The strongest activity occurs at 0:34.

Update 08/12 - 11:34 UTC
- Smoking lava stones can be seen intermittently which proves that the vent is still active.
- We are happy that the best webcam (RTVC) is working again.
- Julio del Castillo Vivero was able to (screen) capture a strong smoking lava block at 11.11.37 this morning. Click here for more activity pictures

Screenshot of the 11.11.37 AM activity - screenshot captured by Julio del Castilo Vivero

Update 08/12 - 08:28 UTC
- We wrote the 07:18 update while it was still dark.
- Reader Max wrote in our comments at 07:33 : Well, regardless of tremor changes, smoking lava stones are still coming up to the surface at 7:30 camera time. It’s still ongoing.
- and .... indeed tremor is gradually picking up again, therefore the eruption continues.

Harmonic tremor from 04:00 until 08:00 - tremor is picking up again (smoking lava stones are still reported) - image courtesy IGN

Update 08/12 - 07:18 UTC
- Harmonic tremor subsided to one of the lowest levels since the eruption started on October 10. After a period of very strong bursts that started yesterday at 22:00, a sudden collapse of harmonic tremor occurred at 04:24 UTC early this morning. We expect that the vent has collapsed due to the strong activity that took place yesterday evening.
What will happen now ?
--1-- As we have had almost no earthquakes for many days, and only medium harmonic tremor, the chance that the activity is subsiding seems very likely. If this is the case, the earthquakes will not pick up again and the eruption will be over.
--2-- If the magma is still very active below El Hierro and if it cannot find an opening any longer via the vent, the earthquakes will gradually pick up again from now on. The pace at which this happens will give scientists clues as to how much power to expect.

Harmonic tremor on December 7 and 8 - image courtesy IGN

Update 08/12 - 00:47 UTC
- Very strong Harmonic tremor which started at 22:00 UTC. Not just bursts but lasting minutes in a row.
- NO earthquakes since midnight.
- 2 small earthquakes yesterday.
- The profile of the eruption changed completely. Harmonic tremor shows constant eruption activity. It seems that the El Hierro volcano wants to join the debate of the alert levels. It looks like it is saying : you counted me out too soon 🙂

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

Volcano Discussion Panel : If you are someone who wants to discuss and read about all aspects of volcanoes, this discussion panel might be a very good place to hang out. Especially when we start speculating about what will happen next, this panel is a great place to check out. Give it a chance.