Vulkaanuitbarsting bij Canarische Eilanden #4

quote:

Update 21/02 – 23:55 UTC
- We are ending the day with 15 earthquakes. 2 of these earthquakes had a magnitude equal or greater than 2.0
- A news article from Spanish news agency EFE, published in La Información (in Spanish), states that several boats will map the ocean depths of El Hierro. Below a summary of the article translated to English:
“The government will start from March 1st a bathymetric survey program (study of the deep ocean) on the island of El Hierro in order to continue monitoring the underwater volcano. This decision was taken today at a meeting chaired by the General Director of Civil Defense and Emergencies, Juan Antonio Diaz Cruz. These actions will take place as long as the eruption continues.
A schedule for the months of March, April and May has been set, with different vessels assigned to do the bathymetry with a periodicity of about 7 to 10 days. Boats will be from the State Navy, Police, Marine Rescue Society, Ministry of Fisheries and Department of Customs.”

quote:

At the risk of being wrong, in the absence of more data comparing the time of arrival of the wave seismographs of the other islands and the data from the USGS, this morning, we had what we understand as a new event in Long Term, typical stratovolcanoes and comienzarían to appear in the system El Hierro, now isolated, the eruptive tremor and apparent shape. An LP, or event of long period, it is a harmonic moviento ie, resonance in a musical note and its harmonics, such low frequency that are not audible, but produced in volcanic conduits for fluids magma. These tubes act as the pipes of an organ. In the seismogram, are characterized by a very slow signal impairment that occurs, generating waves of various kinds. Enclosed is a summary of the most characteristic types of LPs, so they can "play" to classify and find out if indeed this is an LP (JR).


En een PDF

quote:

Update 23/02 – 08:17 UTC - is El Hierro resembling Hawaii ?
- The earthquake activity continues as IGN listed 6 earthquakes so far today
- In our title we talk about Hawaii. Why ? Because a lot of scientists (not all of them) are convinced that both Hawaii and El Hierro are Hot Spot volcanoes, this contrary to subduction volcanoes like the Andes volcanoes (subduction means that the Oceanic plate dives below the continental plate and that part of the re-melted oceanic plate does create volcanoes by fissuring into the continental plate.

In case of Hot Spot volcanoes, we are (simplified) talking of weak points in the oceanic plates. The solid rock part of these plates (the crust) is very thin (10 to 15 km), below this thickness a variety of hotter material creates other sections (that is one of the main reasons why most of the earthquakes are occurring at a depth of 10 km or more). Magma tries to find weak areas in this material. This process can be found all over the ocean floors where hot vents and submarine volcanoes (if extinct also called seamounts) are doing exactly the same (there are thousands of them).
The Kilauea volcano on Hawaii, Hawaii (the big island) is just like El Hierro the youngest island of a volcano chain that grew above sea level. The older islands are moving away from the weakest point by the normal moving oceanic plates (10 to 100 mm per year depending on the location, which makes hundreds of km’s over millions of years). Maui, another extinct volcano island in the Hawaiian chain can be compared with La Palma, second youngest island in the Canary island chain.

The Kilauea volcano at Hawaii is constantly active since many years. Some periods are calm, but nevertheless the lava lake is partly filled and the eruption continues by channeling magma through lava tubes to the ocean. At regular times the eruption process intensifies and creates high intensity eruptions like a full crater lake, creating a stream of lava or even rift eruptions along the crater line. What El Hierro experiences at the moment is almost the same. Early November, a submarine rift eruption occurred (see video and pictures Guardia Civil / Involcan) and since many months the cone builds up by flowing lava (even today with limited HT).
Main difference with Hawaii : the depth of most of the earthquakes. The cracks in the Hawaiian crust are in average at a depth of 4 to 6 km, a lot shallower than the average El Hierro quakes.
We hope that “Wally” the ROV on board of the Atlantic Explorer will soon give us a proof of what is happening near the El Hierro main vent. If the crew of the Atlantic Explorer would succeed in delivering footage of the eruption, it would be a big blame to the other agencies working on this eruption.

quote:

Update 26/02 – 17:53 UTC
- Strong degassing is currently going on
- 6 more earthquakes and 10 in total. Depth in between 10 and 12 km
- minimal harmonic tremor even with this strong degassing

quote:

Update 28/02 – 19:20 UTC
- The depth of the cone is now 100 meters according to twitter from Cabildo de El Hierro, @PrensaElHierro. They also comment that there is a decrease in seismicity, deformation and gases release.

quote:

NOTE AVCAN 464 - QUAKE-VOLCANIC ACTIVITY - IRON ISLAND - FEBRUARY 29 2012-11:00 pm peninsular - seismic-volcanic activity remains moderate, with seismicity today in the area of side peaks at the height of Julan Tanganasoga. Yesterday was in the del Golfo escarpment east of Tanganasoga and in the sea de las Calmas. Continues to be quite microseismicity detected but not located in the spectrogram. Continued volcanic tremor signal in the eruption of La Restinga, which remains low but is rising from day before yesterday, so it has already doubled the signal strength. New earthquakes five low Revised manitud +11. Magnitude of the new earthquakes between 1.7 and 0.8. Depths to 7.4, 8.6, 11.0, 11.6, 16.8 km). Yesterday 14. Yesterday 8. 3 are today. A total of 12,466 earthquakes are located in El Hierro by IGN from 9:00 am of July 19, 2011 (Enrique).

DAY 29 FEB EARTHQUAKES. - Light green (3)
DAY 28 FEB EARTHQUAKES. - Light green (8)
DAY 27 FEB EARTHQUAKES. - Violet (14)
DAY 26 FEB EARTHQUAKES. - Pink (22) - 10 new

The earthquakes in recent days continue to occur in the NNE-SSW alignment from Frontera Sea de las Calmas and another thing to think that earthquakes are concentrated in the central area of the island and there are some more in the Mar de las Calmas. (Enrique)

quote:

Update 28/02 19:20 UTC
- The depth of the cone is now 100 meters according to twitter from Cabildo de El Hierro, @PrensaElHierro. They also comment that there is a decrease in seismicity, deformation and gases release.

quote:

@PrensaElHierro
The process of normalization of the eruptive process in # ElHierro. The cone is 100 meters, according to IEO.

quote:

Update 02/03 – 23:42 UTC
- 4 more earthquakes , which bring the total to 5 today. Magnitudes were higher in average than during preceeding days : 1.8, 1.3, 1.9, 1.5, 2.0 and 1.2
- At least 2 faint jacuzzi’s today
- A further slight increase in HT (thank you ER reader Volcanomen). Wind is sometimes a disturbing element, but not in this case. Wind goes mostly down after sunset and the sea was rather calm tonight although HT still grows bit by bit. It cannot be excluded that HT suddenly inflates again. Lets keep our eyes open the following hours as any increase in activity may be well seen at the surface waters.
- The webcam has been set to very sensitive vision tonight. If a jacuzzi would form it will be easy to see it on the present settings.
- The webcam operator has been focusing on the sunset tonight ? The webcam turned into a romantic observer !

quote:

NOTE AVCAN 467 - QUAKE-VOLCANIC ACTIVITY - ISLA DEL HIERRO - 03 MARCH 2012-11:30 h peninsular - seismic-volcanic activity remains moderate, with seismicity in the summit today and one in the sea de las Calmas. Yesterday afternoon at sea to N del Golfo, the del Golfo escarpment and the area of peaks, also give the Mar de las Calmas in NNE-SSE alignment. Continues to be quite microseismicity detected but not located in the spectrogram. Continued volcanic tremor signal in the eruption of the Restinga, which remains low even from the day February 26 is rising slowly but surely, now more than three times the lowest signal that day. New earthquakes 9. Magnitude of the new earthquakes between 2.2 and 1.2. Depths 10.6 and 13.8km (and two in a row to 21.0 and 24.2km). Yesterday 8. Yesterday 7. 4 are today. A total of 12,492 earthquakes are located in El Hierro by IGN from 9:00 am of July 19, 2011 (Enrique).

MAR. - Dark Blue (4)
DAY 02 MAR EARTHQUAKES. - Yellow (7)
DAY 01 MAR EARTHQUAKES. - Light Blue (8)
DAY 29 FEB EARTHQUAKES. - Red (4)
DAY 28 FEB EARTHQUAKES. - Light green (8)
DAY 27 FEB EARTHQUAKES. - Violet (20) - 6 new
DAY 26 FEB EARTHQUAKES. - Pink (22) - 10 new

The seismicity map of what we have today concentrated 3 close together in the area of peaks and a solo by el Golfo while yesterday afternoon from the N in the Sea to the south through all areas but lining up some in the directions NNE-SSW and NNW-SSE. The previous day there is seismicity is diffuse in the Mar de las Calmas, the Julan, in el Golfo. On 29 morning in the area of side peaks at the height of Julan Tanganasoga. the 28 was in the del Golfo escarpment east of Tanganasoga and in the sea de las Calmas. The earthquakes in recent days and the new revised from 26 and 27 were continuing in the NNE-SSW alignment from Frontera Sea de las Calmas and another thing to think that earthquakes are concentrated in the central area of the island and there are some more in the Mar de las Calmas (Enrique).

1129851 02/03/2012 17:06:55 27.6632 -18.0436 13.8 1.9 mbLg SW EL PINAR.IHI
1129860 02/03/2012 19:27:57 27.8900 -18.0802 21.0 1.5 mbLg NW FRONTERA.IHI

1129854 02/03/2012 19:28:10 27.8152 -18.0645 24.2 2.0 mbLg NW FRONTERA.IHI
1129866 02/03/2012 22:25:43 27.7052 -18.0553 12.2 1.2 mbLg W EL PINAR.IHI
1129878 02/03/2012 22:59:39 27.7300 -18.0455 12.1 1.4 mbLg SW FRONTERA.IHI

1129879 03/03/2012 01:09:12 27.6656 -18.0647 1.4 mbLg SW EL PINAR.IHI
1129909 03/03/2012 06:41:42 27.7108 -18.0378 11.5 1.5 mbLg W EL PINAR.IHI 12490

1129908 03/03/2012 06:41:58 27.7158 -18.0329 10.6 1.7 mbLg W EL PINAR.IHI
1129910 03/03/2012 06:59:44 27.7123 -18.0344 11.0 1.2 mbLg W EL PINAR.IHI

quote:

Update 06/03 – 15:25 UTC
- The red alert in the volcanic area of El Mar de las Calmas has been lowered to Yellow Alert, pre-emergency phase. The rest of the island will continue in yellow alert.
- The exclusion of areas of Arenas Blancas, Tacorón and Playa de Los Mozos will be also relaxed once a new document is released, soon, with the details of a smaller exclusion area. For now, the 4 mile maritime exclusion will remain.
- Recommendations for not swimming, fishing and scuba-diving will remain in place until new samples from the water in the area are analysed by the public health service, which could mean also these measures to be relaxed.
- All this information, in Spanish, from the press release here.

quote:

Undersea Eruption Emergency Ends in Spanish Island

Madrid, Mar 6 (Prensa Latina) The authorities in the Canary Islands decreed on Tuesday the end of the emergency phase in the underwater volcano eruption area started in October last year at El Hierro Island, as informed by head of the Volcano Risk Civil Protection Plan in the Canary Islands (PEVOLCA), Javier Gonzalez.

He said the red alert in La Restinga fishing town was changed to yellow (pre-emergency) now.

The decision was announced a day after the scientific committee of PEVOLCA proclaimed the end of the volcano eruption registered in Las Calmas Sea, south of El Hierro Island.

Experts consider that though there is still some seismic activity, the eruptive phenomenon has concluded, six months after its start.

According to Carmen Lopez, from the National Geography Institute, the eruption phase has ended because no evidence of gasification or emission of material to the surface has been registered, in relation to the eruptive process started in October.

"We are still registering seismic activity, an indicator that the volcanic process is still on," she added.

According to the latest data registered in the area, the main cone of the undersea eruption is 288 feet from the surface.

Since mid July, 2011, El Hierro, the smallest, least populated island of the Canaries archipelago (268 square km and more than 10,000 inhabitants), has suffered over 11,000 quakes caused by magma activity on its subsoil.

The most powerful of them, of 4.6 degrees, was registered on November 11, 2011, and was also felt in Tenerife and La Palma islands.

The Canaries autonomous community is the active area with greater seismology risk in Spain, according to the country's Geology and Mining Institute.

Four of the Caraty Islands have historic volcanoes: El Hierro, La Palma (the Teneguia volcano), Tenerife (Teide volcano) and Lanzarote (Timanfaya volcano). La Restinga's eruption has been the first in this European country since 1971, when the Teneguia volcano erupted.

quote:

NOTE AVCAN 471 - QUAKE-VOLCANIC ACTIVITY - ISLE DEL HIERRO - 07 MARCH 2012-12:30 h peninsular - seismic-volcanic activity remains moderate, with seismicity Today at Sea de las Calmas and west of the Island in the Sea, and yesterday in the sea de las Calmas, all in a NW-SE alignment. Microseismicity continues to be detected but not located in the spectrogram CHIE sensor. Continued volcanic tremor signal in the eruption of Restinga, increasing in the last 24 hours, although the signal remains low. The traffic light area is no longer eruptive or Red Siege to move to Amarillo to be terminated from the emergency phase of the PEVOLCA yesterday. All Island continues with the yellow light indicates volcanic risk alert, have more than one abnormally relevant parameter from the mean.

New earthquakes 3 +1 reviewed. Magnitude between 1.9 and 1.5. Depths to 7.1, 10.7 and 37.2km. Yesterday 4. Yesterday 2. Today will 2. A total of 12,512 earthquakes are located in El Hierro by IGN from 9:00 am of July 19, 2011 (Enrique).


DAY 07 MAR EARTHQUAKES. - Pink (2)
DAY 06 MAR EARTHQUAKES. - Red (2)
DAY 05 MAR EARTHQUAKES. - Light Green (4)
DAY 04 MAR EARTHQUAKES. - Brown (2)
DAY 03 MAR EARTHQUAKES. - Dark Blue (7)
DAY 02 MAR EARTHQUAKES. - Yellow (7)

In simicidad map of the last days, as today is again in the sea de las Calmas and a very deep (37.2) to the west of the island in the Sea Yesterday seismicity was located in the sea de las Calmas , and with today are all in a NW-SE alignment with one of previous days. Before yesterday we had 4 earthquakes aligned in a NNE-SSW in Frontera, the Julan and the Mar de las Calmas. On March 4 there were two in the Julan. On March 3 there were 4 earthquakes close together in the area of peaks at about 10-12km and the rest of the seismicity in the Mar de las Calmas. On day 2 we had instead more and more moderate seismicity N, in the sea of the Gulf, the Gulf and area of peaks and one in the Mar de las Calmas (Enrique).

quote:

Update 08/03 – 18:51 UTC
IEO the Spanish Oceanographic institute has released the results of the 11th bathymetry session (BIMBACHE1011‐11) . The cone depth was revealed already in the beginning of the week (88 meter depth).

La Restinga, El Hierro 10th March - Waves or Jacuzzi? 18:55 - 19:55 UTC

quote:

The eruption of the Mar de Las Calmas is ongoing against the decisions of PEVOLCA, IGN and authorities (Fernando)

quote:

Update 14/03 – 16:00 UTC – IMPORTANT UPDATE!
- The Atlantic Explorer has been able to obtain images of the volcano! They are the first to capture the submarine volcano in ‘El Mar de las Calmas’. The crew of QSTAR along with members of ‘Universidad de las Palmas de Gran Canaria’ and SOS Océanos worked very hard for this achievement. We should expect a detailed report tomorrow as Joke Volta reports.

quote:

Update 15/03 – 22:31 UTC
- AVCAN reports that the Atlantic Explorer ROV Wally has fairly good images of the crater, gas emitting vents and even lava streaming out of the crater ! (what would e really a surprise as the PEVOLCA scientists have claimed that the eruption has ended.
- The ACN press / El Pinar webcam will end his broadcast on March 17. We have to admit that with tyhe present activity, the ACN press webcam was not important anymore as jacuzzi and stain are to faint to be seen
- Maria from SOS Oceanos wrote us in the morning that the ROV pictures will be published “when the University of Las Palmas” thinks it is opportune to do so. Well, we will have to wait then. The law of scientists and Universities is prevailing. The University of Las Palmas has chartered the Q-Star Atlantic Explorer and the ROV and keeps the images first for scientific purposes. We will bring it to you as soon as it is published.

Banco de peces que convive con el volcán submarino.avi

Flanco suroeste del cono principal del volcán submarino.avi