[aktueel] Vulkaanuitbarsting bij Canarische Eilanden #3

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Op woensdag 14 december 2011 20:57 schreef Tokamak het volgende:

[..]

Nouja, niet alleen rood. Ik zie ook blauw, groen, geel, paars en oranje voorbij komen

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15/12/2011 @ 09:01 – The IGN has confirmed the stabilisation of the underwater eruptive process in shallow waters to the south of La Restinga as there is a marked decrease in seismicity, reaching the lowest values ​​since the eruptive process began on 10th October 2011. They have said that in the current situation is not considered necessary to maintain constant 24 hour surveillance. It will continue monitoring the activity and its assessment in terms of scenarios, and the issuance of periodic reports and decision making.

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Update 15/12 – 08:04 UTC
PEVOLCA will stop its 24 hours surveillance in La Restinga but the Center for Permanent Care (CAP) will stay open at La Restinga from 08:00 until 20:00 daily. In between 20:00 and 08:00, people will have the possibility to call a guard able to give answers to most questions or urgencies. Pevolca (based on the data delivered from IGN) says that there is NO indication the the process is deteriorating or is becoming more dangerous. IGN reported the eruption process to be stabilized.
Pevolca also said that if whatever new indication of a reactivation will be noticed, they will return to 24 hour surveillance instantly. The decision has no influence on the alert levels currently in place at the Island (yellow alert at the entire island and red alert in a radius around the Las Calmas sea vent).
Earthquake-Report.com who follows the eruption process from the very beginning confirms that the IGN prognosis have always been right until now, although it was often criticized. The alerts were initially called for the landslide risks and the weak to moderate earthquakes in the El Golfo and Puerto Naos areas and as it was not sure in which area the volcano would show up (since the beginning of the eruption on October 10, there were never other vents localized except the line of the current vent (multiple vents at the beginning of November along the Naos coast). (source Joke Volta and the local press)

Data Update 15/12 – 07:59 UTC
- NO earthquakes since midnight
- very strong rise in general harmonic tremor at 01:21 UTC tonight. 40 minutes later back to medium. Bursts as intensive and as much as yesterday. Longest bursts lasted almost 10 minutes
- vent outlet is very defined this morning due to the strong westerly current
- IGN said yesterday that some bursts of harmonic tremor are being felt by local people in La Restinga
- stain as usual

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The nightly burning boat the final word of a volcanologist
Hmmm. I have carefully watched the videos of the strange lights recorded by the web cams on the evening of 14 December, and I am more than ever convinced that they are absolutely NOT related to volcanic activity, take a volcanologists word for it. The way the lights are moving from about 02:30 min in the second (shorter) of the night videos is clearly indicative of a ship. Theres no way in the physical word that incandescent rock will remain persistently incandescent when its in the middle of water, any piece of incandescent rock would be chilled and lose its incandescence at least on the surface.
Boris Behncke from the INGV-Osservatorio Etneo, Catania
[bron]

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Update 15/12 – 08:04 UTC – Why a ship ?
- As you all know IGN almost immediately said that is was a boat. The reason why will be explained a little later in an interview we will publish from Joke Volta with Carmen Lopez, chief scientist of IGN at El Hierro.
- People of El Pinar went to the viewpoint and said also “it is ‘probably’ a boat“.
- Joke talked to a number of people and they said that they had seen a boat at the Lighthouse horizon of the Las Calmas sea.
- Next, Joke looked with her binoculars from El Pinar high above the sea and could see some lights at the horizon.
As Joke knows the location of the vent very well, she was more or less convinced that it could not have been the vent but what else than a boat. The location of the webcams is totally different as they are installed on a hill near La Restinga. We @ ER started looking into to real time navigation maps, but we could not detect a ship to the south of El Hierro.
- This morning she saw this boat again and she started looking in the internet for the name and position. She made a picture this morning and indicated the different positions she saw it (see image below).
- Paul, a ER reader traced the boat this morning on Marinetraffic.com and on http://www.localizatodo.com . The ship was recognized as the C-Whale (see picture below). Paul also said that the only reason we have not seen this ship on the map during the evening and nightly hours must have been that it had switched off his transponders. Why ? Why was it hanging around in that area ? What was he burning ? It does not look like they had a barbecue on board. Nobody knows.
All other questions (easy to come up with more than 5 immediately) will never be solved.
Once again thanks to all for cooperating on this issue. This story has now been finalized.

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Data Update 15/12 15:30 UTC
- NO earthquakes since midnight below or around El Hierro
- OGN has a 1.7 earthquake listed, but the epicenter is located in between Tenerife and Gran Canaria, nothing exceptional
- People living at the Canary Islands looking regularly on the islands seismographs might see the signals of the M 6.3 earthquake at the Kermadec Island (Pacific Ocean) showing up on the seismogram (after 10:10 UTC).
- at 15:40 UTC the vent surface waters showed renew Champagne activity (lot of bubbles)
- harmonic tremor continues to be above medium with regular powerful hydromagmatic bursts (they are sometimes felt in La Restinga)

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Something has changed in the Tremor, but for over an hour no explosions hydromagmatic, Will has taken pressure and keeps out the water in the canal?, The truth is that it has changed their behavior and the explosions have stopped a while. I still no explosions or resume after a while .. see (Enrique)
[bron]

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Data Update 15/12 23:21 UTC
No more earthquakes and a collapse of harmonic tremor at approx. 18:00. The subsiding process started at 13:00 UTC when we saw a period of limited less energized bursts (could be seen on the webcam). It picked up a little bit in the late afternoon to subside almost to 0 around 20:15. At 20:40 we had a new (limited burst) lasting 8 minutes and since then the signal has been stabilized. Another indication of subsiding activity is the lack of bursts during the last several hours.
In a short interview Joke Volta had with Carmen Lopez from IGN earlier today, Mrs. Lopez reiterated that the decision of delegating the nightly surveillance to Madrid had been taken because seismicity (earthquakes) had almost completely stopped and because harmonic tremor was more or less stabilized. The current data analysis showed a stabilization or even subsiding eruption. As far as the signals are this evening the volcano seems to obey and the eruption has drastically subsided.
It might have been a collapse of the vent, as it occurred a number of other times, but during the past processes the earthquakes picked up soon after the collapse. As there is still a remaining signal at the moment the eruption is continuing at a far lower almost survival level (Christmas and New Year holidays vacation ?).
The following hours and days will be decisive for this eruption. If enough magma pressure is left to reopen the vent the activity may increase again. (to be followed)

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Update 15/12 23:55 UTC
One of the people posting a comment in Shipspotting.com, a specialized shipping blog had the following comment on the hanging around location of the C Whale last night :
the most likely scenario is awaiting orders. The tanker market is very poor at the moment and has been for several months. Its certainly not unusual in such circumstances for ships to hang around in the same area doing nothing for weeks, sometimes months on end. The area around the Canary islands is geographically important in this respect as its on the junction of major seaways and means that vessels can go East or West easily should orders come in

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NOTE AVCAN 384 - EARTHQUAKE ACTIVITY-VOLCANIC - HIERRO ISLAND - DECEMBER 15 2011-22:00 h peninsular - seismic-volcanic activity continues to moderate, without seismicity located in the Hierro, but with some weaknesses detected event (18:47, 19: 05 and 11:08 h). Continue an important sign of volcanic tremor in the Restinga area, with an amplitude that was still rising, and is now down and much in the latest hours. In addition, numerous explosions, possibly hydromagmatic, who introduced every few minutes, have stopped at about 13:20 h. At 18:00 h starts to decrease drastically the tremor signal. No new earthquakes located. Before yesterday 0. Yesterday 1. Now go 0. A total of 11,932 earthquakes are located in El Hierro by IGN from 9:00 am of July 19, 2011. (Enrique)

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Data Update 16/12 09:18 UTC
- NO earthquakes since midnight (the latest El Hierro related earthquake occurred on December 14 at 04:02)
- Harmonic tremor gradually picked up since it collapsed yesterday. At this moment it has reached again what we called the main medium tremor from the last couple of days (filled up blue graph). The biggest change is however that the burst are gone, in other words hydromagmatic activity is minor to none.
- The stain is still visible on the eruption webcam in a very windy Las Calmas sea. The active stirring vent cannot be seen anymore.
- Harmonic tremor is still to unstable to allow a prediction of what to come. Will it stop or reactivate ? We will keep you updated.

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Each Wednesday the Volcanological Institute of Canaries will release a weekly graphical informative report about the seismic-volcanic activity of El Hierro (GUAYOTA El Hierro Island), with data about gas emissions (geochemistry), thermometry (geophysics), deformation (geodesia) and seismicity (geophysics) registered by IGN. Besides that, the usual monthly reports about El Hierro will continue.

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NOTE AVCAN 385 - EARTHQUAKE ACTIVITY-VOLCANIC - HIERRO ISLAND - DECEMBER 16 2011-11:30 h peninsular - seismic-volcanic activity continues to moderate, without seismicity located in the iron, and with some weak events detected (00:26 and 03: 30). Continue an important sign of volcanic tremor in the Restinga area, with an amplitude that after the minimum at 20:30 h yesterday, rose rapidly until midnight, and now continues with a lighter rise in the latest hours. In addition, notice some explosions, possibly hydromagmatic, weak, especially after 3 am. No new earthquakes located. Before yesterday 0. Yesterday 1. Now go 0. A total of 11,932 earthquakes are located in El Hierro by IGN from 9:00 am of July 19, 2011. (Enrique)

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A pulse of seven minutes in the tremor changed the upward trend in recent days
[bron]
A pulse of seven minutes in the tremor changed the upward trend in recent days
IGN scientists are not aware that there have been issuing new magmatic material

A pulse of tremor associated with submarine eruption of El Hierro, extraordinarily long, yesterday marked a change in its evolution. Thus, starting at 13:02 hours decreases the frequency and amplitude of the pulses to decay significantly on 18:20 hours. The oscillation of these pulses is considered normal in the evolution of the eruptive phenomenon is visible on the surface. In the stain clearly shows a dark brown head, fairly bubbling in the middle, and a green area, which confirms the presence of gases. IGN scientists are not aware of new magmatic material has appeared on the surface. On the GPS deformation monitoring stations recorded the same pattern of recent days, following the trends of stability in both the vertical component in horizontal components.

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Update 16/12 – 17:59 UTC
- Very unstable harmonic tremor with a couple of very strong bursts in between 16:00 and 17:00. To soon to predict whether the eruption will stop or continue. After each burst the tremor seems to subside strongly and is picking up a little later.
- The UStream webcam from the El Pinar authority is delivering the best images this afternoon. Sometimes, our imagination sees very faint stirring activity.
- Joke had a chat this morning with the RTVC webcam operator. He said that the strong wind was very uncomfortable and that he was allowed to return home today. So, thanks to Joke we know that this webcam (the best of all webcams) is manually operated as well as the reason why ha was down today!
- Joke said that the stain was still visible from above La Restinga but no activity in it
- She also went to the CAP, science center, and had a talk with the IGN man of duty.
- Joke saw the helicopter flying over this morning, so probably we will have new images and video late tonight

Update 16/12 – 23:59 UTC
- Involcan and the Guardia Civil Helicopters made a surveillance flight today. You will see that the eruption has subsided a lot as could be seen on the harmonic tremor graph, but she is still continuing at lesser pace. The gray eruptive vent remained visible and the stain was still very large.

Data Update 17/12 – 09:19 UTC
- A new earthquake measuring 2.3 magnitude occurred 22 km deep below Los Llanillos in the El Golfo area. It will trigger mixed feelings for 2 groups of people. At the one hand the volcano enthusiasts who will see it as a sign that the volcano is not dead yet and at the other hand the local people who are highly irritated with this activity.
- Harmonic tremor was medium all night long with a slightly increasing trend and some occasional short bursts. Yesterday, the tremor subsided strongly after every burst, but this does not happen anymore since 01:00.
- A faint Jacuzzi area can be seen at times in the Telefonica Cabildo eruption webcam (look at the thin white line 1 cm lower than the horizon and vertically above the left harbor wall. The rough see if sometimes blocking the view, but we have seen it many times this morning

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NOTE AVCAN 387 - EARTHQUAKE ACTIVITY-VOLCANIC - HIERRO ISLAND - DECEMBER 17 2011-10:00 h peninsular - seismic-volcanic activity continues to moderate, with seismicity in the Gulf and some weaker event detected. Continue an important sign of volcanic tremor in the Restinga area, with an amplitude that continues with a lighter rise throughout the day with some explosions, possibly hydromagmatic. The magnitude of the earthquake only 2.3. New earthquakes 1. 22km depth. Days ago 1. Yesterday 0. Today they 1. A total of 11,933 earthquakes are located in El Hierro by IGN from 9:00 am of July 19, 2011. (Enrique)

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Update 17/12 15:03 UTC
- The readings of harmonic tremor of the last several hours are indicating that the eruption is not over yet. Medium tremor is not subsiding as strong as before and bursts are again picking up in number.
- Afternoon back-light /glare is blocking a good view of the eruption area in the Las Calmas sea. We expect a better view on what is happening within 2 to 3 hours.
- Joke is a frequent visitor of the CAP / IGN science center in La Restinga and was informed yesterday that IGN has 3 webcams serving their team.
- Carmen Lopez told Joke the day before yesterday that the closure of the La Restinga nightly surveillance will not have any impact on the 24 hours service they are delivering. The eruption is continuously monitored for 24 hours, but in between 20:00 and 08: 00 it is monitored from Madrid. In case of necessity (Madrid seeing some important change) or whenever local people are alerted in La Restinga, the local La Restinga guard will be operational again. If an important change would be noticed, Pevolca will decide immediately to restart the local 24 hours surveillance at La Restinga. Carmen said to Joke that the continuous 24 hours operations are having a serious burden on the IGN personnel. Delegating the follow up to Madrid during the night allows them to work at more comfortable hours.

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NOTE AVCAN 388 - EARTHQUAKE ACTIVITY-VOLCANIC - HIERRO ISLAND - DECEMBER 17 2011-22:00 h peninsular - seismic-volcanic activity continues to moderate, with seismicity in the Gulf and some weaker events detected, including a microseismic swarm from 19:06 to 19:23 h. Continue an important sign of volcanic tremor in the Restinga area, with a stable amplitude continues throughout the day, with some explosions, more and more numerous, possibly hydromagmatic. The magnitude between 1.4 and 1.0. New earthquakes 2. 3km depth. Days ago 1. Yesterday 0. Now go 3. A total of 11,935 earthquakes are located in El Hierro by IGN from 9:00 am of July 19, 2011. (Enrique)

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Update 18/12 – 09:20 UTC
- Bad news for the volcano fans-followers among our readers. The eruption is subsiding further and looses more and more strength.
- We do not know whether there is a direct connection with what happened yesterday afternoon as it can not be linked with the harmonic tremor graph, but we think that there is certainly an indirect relation. Yesterday afternoon 2 weak earthquakes occurred at very shallow depth in the coastal El Golfo area. The first one occurred at 15:24 had a magnitude of 1.0 and occurred at a depth of 3.4 km. The second one occurred 1 minute later, had a magnitude of 1.4 and occurred at a depth of 3.0 km.

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NOTE AVCAN 389 - EARTHQUAKE ACTIVITY-VOLCANIC - HIERRO ISLAND - DECEMBER 18 2011-10:30 h peninsular - seismic-volcanic activity continues to moderate, without seismicity located in the Hierro, but with some weaknesses detected event (04:49 and 08: 45). Continue an important sign of volcanic tremor in the Restinga area, with an amplitude that continues to decrease since the last part more than 50% to half of the signal, with some explosions, possibly hydromagmatic. No new earthquakes located. Before yesterday 0. Yesterday 3. Now go 0. A total of 11,935 earthquakes are located in El Hierro by IGN from 9:00 am of July 19, 2011. (Enrique)

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The INVULCAN continues to record a decrease in the diffuse emission of CO2 by the volcanic system island of El Hierro

This downward trend since late November until now reaching 770 ± 30 tonnes per day

Since last July, scientists at the Institute of Technology and Renewable Energies (ITER), an agency of the Cabildo of Tenerife, and is now part of volcanological Institute of the Canaries (INVULCAN), 10 500 have been more diffuse flow measurements carbon dioxide (CO2) through numerous scientific campaigns on diffuse volcanic gas emissions that have materialized over the entire surface of the island of Isla Meridian. The latest results confirm a downward trend in the diffuse emission of carbon dioxide (CO2) into the atmosphere by the volcano island of El Hierro since late November, when it came to achieving the 2398 ± 115 tons per day, until now reaching to register for an emission rate of 770 ± 31 tonnes per day.

This record to the bottom of the diffuse emission of carbon dioxide (CO2) suggests a potential loss of pressure carbon dioxide (CO2), from late November to date, the system magmatic-hydrothermal volcanic-existing in the Island El Hierro. These results are consistent with the records of seismic activity as well as horizontal and vertical shifts that are registered through permanent instrumental network

The scientific purpose of these campaigns is to investigate spatio-temporal variations of the diffuse emission of carbon dioxide (CO2) into the atmosphere by the volcanic system of El Hierro island since the results thereof can not be obtained through networks permanent instrumental analysis contribute to the evolution of the current eruptive phase is occurring in El Hierro. On the other hand, it is widely accepted that the gases are the driving force of volcanic eruptions and monitoring of carbon dioxide (CO2) in volcanic surveillance programs is very important because not only is the second major component of volcanic gases after water vapor, but also because of its low solubility in molten silicitados (magma) favoring the carbon dioxide (CO2) to escape with their ease of volcanic systems in depth.

These scientific surveys have failed to materialize due to MAKAVOL project "Capacity Building of R + D + i + d to contribute to the reduction of volcanic risk in the Macaronesia (MAC/3/C161)" which is being co-funded by the transnational Cooperation Programme of the European Union Madeira-Canary-Azores (MAC 2007-2013) and the collaboration of the Island Councils of Tenerife and El Hierro.

INVULCAN is an institution demanded unanimously by the Senate (2005), Parliament of the Canary Islands (2006) and House of Representatives (2009) with the aim of contributing to improving and optimizing the management of volcanic risk in Spain.


Picture Pie
Temporal evolution of the diffuse emission of carbon dioxide (CO2) in the island of El Hierro (red circles) recorded by the INVULCAN and the daily number of earthquakes located above magnitude 1.7 by the National Seismic Network (IGN).

[bron]

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NOTE AVCAN 390 - EARTHQUAKE ACTIVITY-VOLCANIC - HIERRO ISLAND - DECEMBER 18 2011-22:30 h peninsular - seismic-volcanic activity continues to moderate, without seismicity located in the Hierro, but with some weaknesses detected event (09:57 and 15: 07). Continue an important sign of volcanic tremor in the Restinga area, with an amplitude that continues to decrease since the last part over 60% in the last 24 hours, with some explosions, possibly hydromagmatic. It seems that in the last hour begins to rebound. No new earthquakes located. Before yesterday 0. Yesterday 3. Now go 0. A total of 11,935 earthquakes are located in El Hierro by IGN from 9:00 am of July 19, 2011. (Enrique)

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Update 18/12 – 23:59 UTC
- Another Involcan / Guardia Civil video from today, but this time with the Panoramic Camera – Video 1 and Video 2
- Involcan confirms that a new vent has opened to the south east of the former vent. The images are similar than those recorded in October. The same kind of vent and stain colors. The vent seems to be limited in size.
- CO2 levels (measured by the Involcan) have decreased further

VUELO CIENTÍFICO INVOLCAN - GC 181211 - VOLCÁN SUBMARINO DEL HIERRO - NUEVOS BURBUJEOS - PANCAM I

VUELO CIENTÍFICO INVOLCAN - GC 181211 - VOLCÁN SUBMARINO DEL HIERRO - NUEVOS BURBUJEOS - PANCAM II

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NOTE AVCAN 391 - EARTHQUAKE ACTIVITY-VOLCANIC - HIERRO ISLAND - DECEMBER 19 2011-10:30 h peninsular - seismic-volcanic activity continues to moderate, with seismicity in the Gulf and with some weak events detected (Wednesday 22:23, 02:20, 3:36, 07:41 and some more). Continue an important sign of volcanic tremor in the Restinga area, with an amplitude that has begun to increase since midnight, in more than 20%, with some explosions, possibly hydromagmatic. The magnitude of only 2.0 earthquake is located. New earthquakes 1. 19km depth. Before yesterday 3. Yesterday 0. Today they 1. A total of 11,936 earthquakes are located in El Hierro by IGN from 9:00 am of July 19, 2011. (Enrique)

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NOTE AVCAN 392 - EARTHQUAKE ACTIVITY-VOLCANIC - HIERRO ISLAND - DECEMBER 19 2011-21:30 h peninsular - seismic-volcanic activity continues to moderate-low, without seismicity localized, but with some weak events detected. Continue an important sign of volcanic tremor in the Restinga area, with an amplitude that has begun to increase since midnight, in more than 30%, with some explosions, possibly hydromagmatic. No new earthquakes located. Before yesterday 3. Yesterday 0. Today they 1. A total of 11,936 earthquakes are located in El Hierro by IGN from 9:00 am of July 19, 2011.


^{[voor de betekenis van de kleurtjes]}

WARNING => FOR THE FALL OF EARTHQUAKE, VOLCANIC ACTIVITY, FROM MORNING BRIEFING NOTE THERE WILL BE A ONE DAY, THE IN THE MORNING. This does not mean that there is any special note if there is a surge of activity. (Enrique)

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Update 19/12 23:30 UTC
- NO more earthquakes this afternoon and evening
- CAP science center in La Restinga has confirmed that the the main vent is probably no longer active but that some minor side vents are now erupting. As we could see on the webcam during the day, the location of these vents is a little more to the north-east. IGN will certainly report on this new activity the following day(s).
- AVCAN (Actualidad Volcanica de Canarias) will decrease his number of daily El Hierro reports to one per day as a result of the subsided activity. They will increase their reporting when the vents would reactivate.