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Earth of fire

Actualité volcanique, Articles de fond sur étude de volcan, tectonique, récits et photos de voyage

Publié le par Bernard Duyck
Publié dans : #volcanic activity
Merapi - fall of incandescent blocks on 12.11.2021 at the beginning of the night - photo Øystein Lund Andersen - one click to enlarge

Merapi - fall of incandescent blocks on 12.11.2021 at the beginning of the night - photo Øystein Lund Andersen - one click to enlarge

This November 12, the Merapi is topped by a white plume at about 100-400 m. above the summit.

Seismicity is characterized by:

- 158 Abortion earthquakes with an amplitude of 3 to 25 mm and a duration of 16 to 190 seconds.
- 80 times bursts of earthquakes with an amplitude of 3 to 5 mm and an earthquake duration of 10 to 34 seconds.
- 6 hybrid / multiphase earthquakes with an amplitude of 3 mm, S-P 0.4-0.8 seconds and an earthquake duration of 9-11 seconds.
- 1 local tectonic earthquake with an amplitude of 4 mm, S-P of 15 seconds and a duration of 40 seconds.
- 1 distant tectonic earthquake with an amplitude of 5 mm, S-P 36 seconds and a duration of 102 seconds.

 

The current potential danger consists of lava avalanches and hot clouds in the south-east-south-west sector for a maximum of 3 km to the Woro river and 5 km to the Gendol, Kuning rivers, Boyong, Bedog, Krasak, Bebeng and White. During this time, the ejection of volcanic material in the event of an explosive eruption can reach a radius of 3 km from the summit.

 

Sources: PVMBG, Magma Indonesia, BPPTKG, photo Øystein Lund Andersen

Merapi - blocks falling continue on 13.11.2021 - photo Øystein Lund Andersen - one click to enlarge

Merapi - blocks falling continue on 13.11.2021 - photo Øystein Lund Andersen - one click to enlarge

The Japanese Coast Guard's Maritime Information Service observed the surroundings of Fukutoku-Okanoba on November 11 during an overflight.

Compared to the observation results of November 1, the Niijima plateau has shrunk slightly. A white fumarole rising from the northern end of Niijima has been confirmed. In addition, a small white circular bubble-like gush was observed on the sea surface on the north side of Niijima.

Dark yellow-green discolored water was observed in an area approximately 3 km in diameter centered on Fukutoku-Okanoba.
About 20 km southeast of Fukutoku-Okanoba, yellow-green discolored water with a diameter of about 2 km and floating material believed to be pumice was observed.

The underwater volcanic activity has not subsided and thermal activity is still active,” said Kenji Nogami, professor at the Tokyo Institute of Technology, aboard the observation flight.

 

Source: Japan Coast guards

Fukutoku -Niijima west - discolored waters on 12.10.2021 - photo Japan Coast Guards

Fukutoku -Niijima west - discolored waters on 12.10.2021 - photo Japan Coast Guards

Cumbre Vieja lava flows remain stable, with continuous emission through the same channels as in previous days.

The VAAC Toulouse has warned of a plume of volcanic ash which has risen to an estimated altitude of 2,400 m or to flight level 080 and is moving at 10 kts in the SW direction.

Likewise, the expansion of the second lava delta continues. The lava affected area is estimated to be 1,009.43 ha., or over 19.3 ha. in 3 days. The number of constructions rose by 11 units, with a total of 2,616.

La Palma - lava flows of Cumbre Vieja at 12.11.2021 / 07:02 UTC - Doc. Copernicus EMSR

La Palma - lava flows of Cumbre Vieja at 12.11.2021 / 07:02 UTC - Doc. Copernicus EMSR

La Palma / Cumbre Vieja - the plumes of the volcano and the lava entrance to the sea merge this 12.11.2021- Photo Guardia Civil via InVolcan

La Palma / Cumbre Vieja - the plumes of the volcano and the lava entrance to the sea merge this 12.11.2021- Photo Guardia Civil via InVolcan

On 2021-11-12, Sentinel-5P / TROPOMI detected a strong SO2 signal at a distance of 4.1 km from CumbreVieja with 73.40DU of SO2 at an altitude of ~ 1km. The mass is estimated at less than 300 km at 24.6 kt.

Seismicity is maintained at depths greater than 20 kilometers, but in decreasing number. Seismicity at intermediate depths remains low and no surface seismicity is recorded.

The most likely interpretation of the seismicity recorded since October, according to InVolcan, is a link to a "readjustment" of the Earth's interior after the large amount of magma emitted during the eruption. In practice, the decrease in volume of the magmatic conduits must be compensated by a readjustment of the rocks which surround them, thus generating the intense seismicity observed. It should be noted that, as observed in other similar volcanic eruptions, the seismicity could persist for weeks, months or even years after the eruption ends.

La Palma - Strong SO2 signal 4.1km from CumbreVieja with 73.40DU of SO2 on 12.11.2021 at an altitude of ~ 1km. - Sentinel-5P Tropomi / DLR / BIRA / ESA

La Palma - Strong SO2 signal 4.1km from CumbreVieja with 73.40DU of SO2 on 12.11.2021 at an altitude of ~ 1km. - Sentinel-5P Tropomi / DLR / BIRA / ESA

La Palma / Cumbre Vieja - seismicity at 12.11.2021 - Doc. IGNes - one click to enlargeLa Palma / Cumbre Vieja - seismicity at 12.11.2021 - Doc. IGNes - one click to enlarge

La Palma / Cumbre Vieja - seismicity at 12.11.2021 - Doc. IGNes - one click to enlarge

Regarding air quality, the daily threshold for sulfur dioxide (SO2) values ​​was not exceeded at any of the stations and only the El Paso station recorded a value above the alert threshold for a short time. time lapse. Regarding particles smaller than 10 microns (PM10), an exceeding of the daily limit value was recorded in the Llanos de Aridane, with an unfavorable index and with an increase during the day yesterday.

 

Sources: IGEM, IGN, InVolcan, Pevolca, Gobierno de Canarias Cabildo La Palma

Piton de La Fournaise - access to the Enclosure at Pas de Bellecombe - archive photo Bernard Duyck

Piton de La Fournaise - access to the Enclosure at Pas de Bellecombe - archive photo Bernard Duyck

After several months of work, a new version of the ORSEC "Volcan" plan, concerning the Piton de La Fournaise, has just seen the light of day. Due to the frequency of eruptions and in view of the unpredictability of the volcano, the new device aims to ensure the safety of people by modifying access to the site, to facilitate traffic flow and to manage gatherings more effectively, authorities say.

The prefect of Reunion, the Volcanological Observatory of Piton de la Fournaise and the local communities worked on the revision of the Specific Organizing Device for the Civil Security Response of the volcano.

Piton de La Fournaise - Zoning of accessible areas following the modification of the ORSEC "volcano" plan on 08.11.2021

Piton de La Fournaise - Zoning of accessible areas following the modification of the ORSEC "volcano" plan on 08.11.2021

Since November 8, 2021, the prefectural decree has therefore changed on the following points:

During the vigilance phase: access to the upper part of the enclosure is limited to 3 marked trails for unaccompanied visitors. Outside these trails, the public must be accompanied by medium mountain guides or high mountain guides.

 

In the eruptive phase (level 1 and 2 alerts), the upper part of the enclosure, the large slopes and the lower part of the enclosure are prohibited from public access.

Only personnel assigned to certain scientific, rescue and information missions for hikers, marking and securing can now access the enclosure during the level 1 and 2 alert phases. Access authorizations will be established from now on. permanent or temporary, depending on the personnel concerned.

 

During the safeguard phase and before field surveys in the upper part of the enclosure, the lower part may be reopened to the public. Regulatory measures for traffic and parking management as well as signage work will be implemented, in conjunction with the communities concerned.

 

Source: France Info Réunion 1 

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