This is Part 30 of the El Hierro Volcano eruption report
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With the collaboration of Joke Volta, an El Hierro resident and Julio del Castillo Vivero, photographer.
Read also : (28/7 - early 09) - (25/09 - 10/10) - (11/10 - 13/10) - (14/10 - 17-10) - (18/10 - 21/10) - (22/10 - 26/10 ) - (27/10 - 31/10 ) - (01/11 - 03/11 ) - (04/11 - 06/11 ) - (07/11 - 08/11) - (09/11- 11/11) - (12/11 - 15/11) - (16/11 - 19/11) - (20/11 - 23/11) - (24/11 - 27/11) - (28/11 - 02/12) - (03/12 - 07/12) - (08/12 - 11/12) - (12/12 - 15/12) - (16/12 - 18/12) - (19/12 - 25/12) - (26/12 - 31/12) - (01/01 - 03/01) - (04/01 - 07/01) - (08/01 - 13/01) - (14/01 - 19/01) - (20/01 - 25/01) - (26/01 - 30/01) - (31/01 - 04/02) - Part 30 (05/02 - 10/02)
Useful links : @VolcanoReport - El Hierro Picasa Photo Album
Our Webcam pages : 3 in 1 page – Las Calmas Ustream – La Restinga village – Eruption webcam
Update 10/02 - 23:57 UTC
- An 7th earthquake occurred at 22:49 UTC at a preliminary depth of 8 km here.
- An 8th earthquake with a magnitude of 2.1 occurred at 23:51 UTC at a preliminary depth of 9 km here.
Important Update 10/02 - 22:57 UTC
- Quiet a surprise today to hear a lot of mixed news reports (or at least confusing messages) from Pevolca, the safety committee managing the possible danger of the eruption. Pevolca is a committee existing out of scientists, authorities, emergency teams, police etc.
Pevolca has given their estimate of the situation with interviews to the local and national press.
- Pevolca sees a decrease of the volcanic activity (as Mr. Ortiz stated earlier this week)
- La Restinga touristic boats are allowed to have aquatic activities at least 4 NM (nautical miles) from the volcano and may navigate max. 450 meter (0.25 NM) along the coast. !
- Pevolca (commenting out of Madrid) has stressed that measures can be changed immediately if conditions would alter and press them to do so.
- the current alert levels and NO-NAVIGATE area remains like it is (except the larger 450 m area along the coast). Until now boats were allowed to enter and exit the La Restinga port close to the coast.
- The RED alert (vent area) and YELLOW alert (island) are maintained.
- El Hierro will receive 5 million euro to gradually normalize conditions of life
- Alpidio Armas is talking with a number of companies to revitalize the El Hierro touristic sector
- UME (emergency division) has been allowed to withdrawn from El Hierro and started their withdrawal on February 3.
+ well, here we have 2 new earthquakes, which brings today's total to 6
10/02/2012 21:43 Depth 10 km M 1.8 SW FRONTERA
10/02/2012 22:49 Depth 8 km M 1.0 SW EL PINAR
Earthquake-report.com opinion : As distant observers from all over the world, a lot of people will have a hard time to understand what is happening here. With an HT still present, occasional strong jacuzzi and with continuing earthquakes going on (some of the most powerful since new year happened last week), we can understand that the treat for the island is manageable, but diminishing the Pevolca report is at least a bit confusing.
What means the "depth" of an earthquake ?
Don, an ER reader just commented as he did not know exactly what we meant with "depth" of the earthquakes. As Don, will certainly not be the only one having this question, we do try to give a simplified answer to his question. We can write 5 pages on this subject bit if we limit it to the essentials, it is mainly the following :
An earthquake has always a breaking point or cracking point. In scientific terms it is called a Focal Depth or Hypocenter. The epicenter is the location on the surface or otherwise said on a flat map. The focal depth is together with the epicenter the most important parameter of an earthquake.
For tectonic earthquakes, the shallower the depth the more dangerous it is. The deeper, the less chance you will feel it. Compare it with an explosion of huge quantities of dynamite. If it explodes 10 km below your house at night, you will almost be ejected out of your bed, if at 500 km you will sleep through it.
For volcanoes the focal depth is important for the location of an eventual vent, outburst. Below a volcano is a complex system of cracks, lava tubes etc. Below 5 km there is no problem. Even 5 km is a huge distance for magma to reach the surface. But if the focal depth is less than 1 km, i can guarantee you that the hairs of the IGN scientists at El Hierro are rising and that adrenaline will stream through their blood.
To make it easy, we use "Depth" instead of Focal depth or hypocenter.
Update 10/02 - 14:10 UTC
- Thursday we have informed you on these pages of an ongoing new eruption (paroxysm = short strong eruption cycle) at Etna Sicily. Julio del Castillo Vivero, the timelapse specialist, has made a great video showing these eruption over the many hours it was going on. Click here to see the video.
Update 10/02 - 14:08 UTC
Joke Volta has sent us a series of beautiful photographs showing Ramón Margalef doing works on the volcanic eruption. Please take a look at the great images Joke made this morning in our Picasaweb. Click on the first image to enlarge and to see the many birds accompanying the oceanographic ship. Click on the second (thumbnails) image to see Joke images of this morning in full size.
Update 10/02 - 12:21 UTC
- New earthquake:
10/02/2012 10:57 Depth 4 km (recalculated to 9 km a few hours later) M 1.7 (recalculated to 1.8 a few hours later) SW FRONTERA
Update 10/02 - 11:12 UTC
- Harmonic tremor keeps increasing in the past hours to low-medium levels.
- The depth of the 10/02/2011 04:45 earthquake was corrected to 11 km. and magnitude lowered to 1.1
- We believe the Ramón Margalef scientific Vessel might be in the process of acquiring images of the submarine volcano as this morning has spent long periods of time above the vents with not much movement.
Update 10/02 - 08:41 UTC
- 2 new earthquakes since midnight UTC/ Especially the shallower earthquake is attracting our attention (if confirmed by IGN). These shallower earthquakes (2 shallow earthquakes yesterday were recalculated to depths of 10 km or more) are very unusual in the El Hierro earthquakes and remember that exactly a couple of shallower earthquakes triggered the start of the eruption in October, this after many weeks of earthquakes. We experienced a similar situation yesterday with 2 earthquakes respectively at a depth of 3 and 6 km. Today's new 3 km depth earthquake must certainly alarming IGN scientists (if true).
- People tend to diminish the strength of the eruption based on what they are seeing in the Las Calmas see, but an eruption is far more than that alone. Lava balloons are not necessarily signs of a shallower depth of the vent as they have been seen at the Azores islands while a submarine eruption took place at several hundred meters of depth.
10/02/2012 01:56 Depth 12 km M 1.5 SW EL PINAR
10/02/2012 04:55 Depth 3 km M 1.2 SW EL PINAR
- Harmonic tremor is very regular, but is increasing bit by bit since yesterday morning.
- Our conclusion : this eruption is not over yet and may carry surprises.
Update 09/02 - 20:41 UTC
- There has been a new earthquake since our last update:
09/02/2012 19:03 Depth 13 km M 1.7 SW EL PINAR
Update 09/02 - 20:01 UTC
- no new earthquakes and continuing HT all day long
- When the volcano wants to be quiet for a while, Joke makes sure that she shows the beauty of El Hierro.
Update 09/02 - 16:08 UTC
- Satellite image from NASA-MODIS-TERRA shows a small green stain in front of La Restinga, El Hierro
- Harmonic tremor continues at low levels with some seismic movements not registered by IGN.
- The Ramón Margalef vessel continues working on the volcano. For the last minutes it has been circulating the same spot, maybe we will have images of the volcano very soon.
Update 09/02 - 10:10 UTC
- Powerful jacuzzi in front of La Restinga.
Update 09/02 - 08:26 UTC
- 3 earthquakes since midnight UTC :
09/02/2012 07:46 Depth 10 km M 0.9 SW FRONTERA
09/02/2012 07:52 M 1.1 NW FRONTERA
- since 04:15 this morning, harmonic tremor has been rising a little bit with sporadic limited bursts
- a stronger than usual Jacuzzi earlier this morning is the result of this rise in HT activity
- we expect to have a reliable Ramon Margalef new depth estimate of the main vent at the end of this week
Update 08/02 - 23:26 UTC
Just a small note to let you know that Etna is still erupting - these eruptions (paroxysmal eruptive episodes) are lasting normally only a couple of hours. If you haven't seen it, be quick or you may be to late to see it in real-time. Se link at the 21:11 update.
Update 08/02 - 23:18 UTC
Remember our update from 17:56 yesterday, when somebody of CAP told Joke that he had seen much stronger activity than usual in the Jacuzzi. ER reader Sissel has recorded the webcam at that time. The 4 minutes video shows the more intense activity. The activity occurred when we lived through 5 minutes of the most powerful HT since many days. The graph can be seen at the end of the recording.
Update 08/02 - 21:11 UTC
For the interested people : Etna is erupting right now ! (Thank you Nataly for telling us)
Update 08/02 - 20:33 UTC
- There have been 3 more earthquakes while harmonic tremor its continuing at minimum levels:
08/02/2012 18:38 Depth 14 km M 1.3 W EL PINAR
08/02/2012 18:51 Depth 12 km M 1.3 W FRONTERA
08/02/2012 19:18 Depth 12 km M 1.3 W FRONTERA
Update 08/02 - 20:32 UTC
- When Pam and New wrote us "SLS", we immediately forwarded the message to Joke who was on her way to El Pinar. She asked the bus driver to stop, got a lift from a friendly person to Montana Naos, took some pictures and hitchhiked again towards El Pinar. These are Jokes pictures.
Update 08/02 - 16:39 UTC
- Just after writing about the calm day, ER readers Pam and New notified us of Smoking Lava Stones.
Update 08/02 - 16:23 UTC
- A calm day at El Hierro with few spectacular events but with the very beautiful pictures of Joke Volta.
- only 1 new earthquake since the last update, but a medium powerful one which can well be seen on the IGN HT graph.
08/02/2012 15:35 Depth 12 km M 2.2 SW EL PINAR
Update 08/02 - 10:21 UTC
- Very minor harmonic tremor all night and morning so far, a little increase in HT at 03:05 for about an hour.
- Jacuzzi activity was very much present all night long in a very sensitive webcam seting. We enjoy this setting for maximum observation at night.
- 5 earthquakes so far today!
08/02/2012 00:42 Depth 14 km M 1.3 W EL PINAR
08/02/2012 00:43 Depth 12 km M 1.3 SW FRONTERA
08/02/2012 02:52 Depth 11 km M 1.4 W EL PINAR
08/02/2012 06:12 Depth 14 km M 0.8 SW EL PINAR
08/02/2012 07:33 Depth 20 km M 1.4 SW EL PINAR
Update 07/02 - 23:02 UTC
- the current high sensitive webcam image shows the action in the jacuzzi. Hard to say what the light effects are (waves or hot material). That will be a question for CAP for Joke tomorrow or the day after tomorrow.
- Harmonic tremor has been minimal for many hours again, but the eruption is still going on.
- 2 new earthquakes that make it a total of 8 today
07/02/2012 20:20 Depth 13 km M 1.0 SW EL PINAR
07/02/2012 22:25 Depth 10 km M 1.2 S EL PINAR
- Readers like Julian have seen the Ramon Margalef continuing his bathymetry mission after dark.
- Images Joke Volta from today February 7 2012
Update 07/02 - 19:30 UTC
ER reader Julian writes in our comment section : In an interview with Ramon Ortiz (Volcanologist of CSIC) in local newspaper Canarias7, Mr. Ortiz says that according to past experiences, the eruptive process is finishing. The new HT increase of the last couple of days are the normal evolution to a new phase.
He says that two different possibilities are: 1- that this process ends in few days and/or a new eruption is going on in another location.
He says that right now there are two different eruptions. The one in Las Calmas, and another one elsewhere which we may never know where it is, beacuse of the depth in the north area.
(ER : the supposedly second vent in the north has been a fierce debate among scientists from the very beginning). We refer to some updates we wrote during the weeks after the coloring of the sea).
Update 07/02 - 17:56 UTC
- A CAP scientists who met Joke in El Pinar a few hours ago said to her that he has seen an extraordinary jacuzzi around noon UTC today. He was quiet fascinated about it.
- We are also fascinated about the strange harmonic tremor we see today. A lot of powerful starts gradually winding down, again and again. Now it is calm again, but we cannot remind having seen the same pattern since a long time. It may be very wise to follow HT the following hours in combination with the webcam.
Update 07/02 - 13:55 UTC
- The Ramón Margalef IEO Oceanographic vessel is back in town. He is making a new bathymetry session enabling IEO to measure the depth of the vent and to make new maps of the submarine cones. Meanwhile the local Canary Island press is quoting local volcanologists who are saying that IEO is not sharing the submarine research details with other (scientific) partners. It will at least take 2 to 3 days to get a new depth figure.
- 4 earthquakes so far today
07/02/2012 02:21 Depth 11 km M 1.0 SW EL PINAR
07/02/2012 10:29 Depth 15 km M 1.4 SW EL PINAR
07/02/2012 10:55 Depth 14 km M 1.3 SW FRONTERA
07/02/2012 11:37 Depth 13 km M 2.3 SW EL PINAR
- Harmonic tremor started to grow gradually after 03:00 as Ursula said in the comments (she lives in Australia and is looking at the HT graph and webcam while most Europeans sleep), winding down just before noon. Very suddenly everything restarted forcefully at 13:32 UTC, although nothing more than degassing can be seen at the surface.
Update 06/02 - 23:55 UTC
- Joke Volta pictures of February 6, 2012. No SLS today.
Update 06/02 - 23:24 UTC
- INVOLCAN has just published two high definition videos of today's flight. We can see how they measured gas levels and took thermal images, which would be useful if they made public. There is a strong degassing, blue stain, that can be observed.
- Second video shows the green stain in La Restinga port.
- Eruption webcam is showing a good view the stain even now that is dark. A near full moon illuminates the sea enough for the camera to capture an image. Also, the webcam was cleaned today for better image quality.
- Another earthquake since our last update
06/02/2012 21:43 Depth 15 km M 1.7 W EL PINAR
Update 06/02 - 21:50 UTC
- One more earthquake since last update:
06/02/2012 18:04 Depth 11 km M 1.7 W EL PINAR
Update 06/02 - 18:02 UTC
- The activity at the eruption site has been quite with almost a constant faint jacuzzi. We haven't seen SLS. Should earthquakes continue, we would expect a rise in the activity.
- INVOLCAN has just published an incredible set of today's photographs taken from the Guardia Civil helicopter flight, showing, as we commented today, a vivid blue stain, formed by gas release, with CO2 bubbles, and a bigger green stain, formed by nitrogen and sulfur gases, that lays inside La Restinga port.
Update 06/02 - 16:05 UTC
- After reading reports of a people feeling shacking at 15:45 in Frontera, IGN published a M 2.6 Earthquake. IGN is publishing earthquakes not in chronological order, so we are updating along as they do.
06/02/2012 15:45:06 Depth 12 km M 2.6 W EL PINAR
06/02/2012 15:26 Depth 12 km M 1.8 SW FRONTERA
06/02/2012 15:00 Depth 14 km M 1.0 SW FRONTERA
06/02/2012 14:11 Depth 11 km M 0.7 SW FRONTERA
06/02/2012 13:26 Depth 6 km M 1.1 SW EL PINAR
- Harmonic Tremor remains low, with a spike from the strong earthquake.
Update 06/02 - 13:10 UTC
- Harmonic tremor increased significantly up to 02:00 and then started decreasing with a minimum commencing at 03:15 and remains like this.
- There have been 4 earthquakes since midnight:
06/02/2012 06:02 Depth 10 km M 0.9 SW FRONTERA
06/02/2012 06:59 Depth 14 km M 1.3 SW EL PINAR
06/02/2012 07:50 Depth 13 km M 1.3 SW FRONTERA
06/02/2012 12:09 Depth 17 km M 1.9 W EL PINAR
- Joke Volta told us the Guardia Civil helicopter was inspecting a much larger area than usual and sent us a photograph of the moment. The middle of the stain has a blue colour that can be clearly seen on the eruption webcam now. Click on image to enlarge.
Volcano Discussion Panel : If you are a person who wants to discuss and read about all aspects of volcanoes, this discussion panel might be a very good place to hang around. Especially if we start speculating about what to happen next, this panel is a great place to look at. Give it a chance.