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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

At Merapi, this January 26, the day was marked by:

- 13 earthquakes accompanying as many pyroclastic flows of collapse, with a seismogram of an amplitude of 25 to 60 mm and a duration of 104.1 to 163 seconds, and a displacement distance of 1,000-1,500 meters towards the southwest and a co-pyroclastic cloud 400 meters above the summit.

- 221 collapse / avalanche earthquakes

- 11 emission / blast earthquakes

- 19 hybrid / multiphase earthquakes

Merapi - 01.26.2021 / 05h53 WIB - photo linawidha / Twitter and in the morning - photo News.CN
Merapi - 01.26.2021 / 05h53 WIB - photo linawidha / Twitter and in the morning - photo News.CN

Merapi - 01.26.2021 / 05h53 WIB - photo linawidha / Twitter and in the morning - photo News.CN

Merapi - 01.26.2021 / 11.53 p.m. - doc. PVMBG

Merapi - 01.26.2021 / 11.53 p.m. - doc. PVMBG

The activity continues on January 27, between midnight and 12 noon local, with:

- 21 earthquakes accompanying pyroclastic flows, with an amplitude of 20 to 60 mm and an earthquake duration of 83 to 197 seconds.

- 129 collapse / avalanche earthquakes

- 5 emission / blast earthquakes

- 1 hybrid / multiphase earthquake.

- a distant tectonic earthquake.

 

The activity level remains at 3 / siaga

 

Sources: PVMBG, Magma Indonesia, BPPTKG, VAAC Darwin, Merapi uncover

Merapi - pyroclastic flow from 01.27.2021 / 07:50 WIB, deviated by the winds - photos Djoksuwarno
Merapi - pyroclastic flow from 01.27.2021 / 07:50 WIB, deviated by the winds - photos Djoksuwarno

Merapi - pyroclastic flow from 01.27.2021 / 07:50 WIB, deviated by the winds - photos Djoksuwarno

Merapi  - Volcanic ash adisory au 27.01.2021 / 09h40Z - Doc. VAAC Darwin  IDY65285

Merapi - Volcanic ash adisory au 27.01.2021 / 09h40Z - Doc. VAAC Darwin IDY65285

The Mayon Volcano Monitoring Network recorded thirty-six (36) volcanic earthquakes and one (1) rockfall event during the last 24 hour observation period.

Moderate emission of steam-laden white plumes were observed moving down the slope before drifting west-northwest and west.

A faint glow from the summit crater could be observed at night. Sulfur dioxide (SO2) emissions were last measured below the benchmark average of 401 tonnes / day on January 26, 2021.

Ground deformation data from continuous GPS monitoring indicates that the building is still inflated compared to July 2019 despite a period of general deflation since July-August 2020, and has been experiencing short-term inflation since November 2020 except on the southwest slope. The edifice's deflation along with the near-term inflation of the northwest slopes since December 2020 has also been recorded by electronic tilt monitoring.

 

Source: Phivolcs

Mayon - degassing and night glow - photo archives 04.02.2020 / Dost-Phivolcs

Mayon - degassing and night glow - photo archives 04.02.2020 / Dost-Phivolcs

Regarding effusive activity, the continuity of growth of the lava dome at the Nevados de Chillán volcanic complex is recognized with a greater advance towards the NNE and an extension of its fragments on the NNE slope, with a range of 100 m. Thanks to the analysis of satellite images (Planet Scope and Pleiades), the morphologies associated with the partial destruction of the surface portion are recognized.

In turn, the emission of the L5 lava flow continues with indications of an acceleration of its emission rate compared to the previous fortnight, and an increase in the opening of the feed crack, with a greater contribution of matter in the proximal zone, recognized by surveillance cameras. Based on the processing of satellite images (Planet Scope, Sentinel L2 A and Pleiades), we estimate a range of 788 m from the edge of the active crater and a forward speed of 0.07 m / h on its front. Through the analysis of digital elevation models, an increase in the total emission rate in December 2020 to 0.2 m³ / s is confirmed, to which is added the acceleration of the L5 dynamic for this fortnight. Until December 2020, a total accumulated volume is measured: 1,401,824 m³.

By processing the available thermal images, maximum temperatures of 333 ° C were observed during the occurrence of explosions and 204 ° C for the L5 lava flow currently located on the northern slope.

 

Source: Sernageomin OVDAS

Nevados de Chillan - A new source of thermal radiation is recorded in the lava flow "L5" and at the emission point of the north dome since 01/23 - image Sentinel L2A / various therm bands. / via Sernageomin

Nevados de Chillan - A new source of thermal radiation is recorded in the lava flow "L5" and at the emission point of the north dome since 01/23 - image Sentinel L2A / various therm bands. / via Sernageomin

Nevados de Chillan - L5 lava flow and recurrent degassing on its front since 01/23. - photos 25.01.2021 / webcam OVDAS- Sernageomin

Nevados de Chillan - L5 lava flow and recurrent degassing on its front since 01/23. - photos 25.01.2021 / webcam OVDAS- Sernageomin

Dr Erouscilla Joseph, director of the UWI-SRC center, said the eruption of the St Vincent soufrière was currently effusive, not explosive, but that could change given the historical activity observed at La Soufrière:

“ Magma gently oozes through a vent and forms a dome. The possibility of this type of eruption going from effusive to explosive exists. This volcano may show both types of eruptions. At the moment, based on the information available to us, it is impossible to meet the final timeline of what is happening, or whether it will happen at all. "

Historical activity of Soufriere and possible types of eruptions - Doc. UWI-SRC

Historical activity of Soufriere and possible types of eruptions - Doc. UWI-SRC

Soufrière de St Vincent - the old dome (in purple) and the new elliptical dome (in yellow, SW) - Doc. 18-19.01.2021 / 21:38 UTC via MTC- Cosmo- SkyMed

Soufrière de St Vincent - the old dome (in purple) and the new elliptical dome (in yellow, SW) - Doc. 18-19.01.2021 / 21:38 UTC via MTC- Cosmo- SkyMed

Dr Joseph said that at present the danger is limited to gases exiting the dome for those working on the summit. There is a risk that, depending on the wind direction, the gases could travel downwind to surrounding communities.

A report has been received of yellowing vegetation in the crater and on a nearby farm, which is likely the result of acid rain.

 

Source: UWI-SRC article / "Be vigilant, be prepared"

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