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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

Explosive activity increased in Fagradalsfjall :

Just before 8:30 p.m. on April 26, there was a phase shift in the activity of Vent # 5 - the southernmost vent of those that opened and have been active since April 13.

The intensity (and vigor) of the explosive activity suddenly increased and began to support a lava fountain 40-50 m high, instead of 10 -15 m. usual. The eruption continues to support a more vigorous fountain on April 27 at 10:30 a.m. (IMO report).

Fagradalssfjall eruption - screenshot 26.04.2021 / 23:40 - webcam RUV Geldingadalur - one click to enlarge

Fagradalssfjall eruption - screenshot 26.04.2021 / 23:40 - webcam RUV Geldingadalur - one click to enlarge

As a result, the lava flow in the "Nameless Valley" has increased dramatically. Additionally, activity in the northernmost vent (# 6) from April 13th appears to have decreased significantly, but the one just south of it (# 4) is still active. Not easy to judge the condition of the original vents in Geldingadalir, but there was still some glow in 'Norðri' last night.

 

Sources : IMO & webcams RUV and mbls

Fagradalsfjall - 04/27/2021 / 3:27 p.m. - Lava fountain supported - mbls webcam screenshot via S. Harangi

Fagradalsfjall - 04/27/2021 / 3:27 p.m. - Lava fountain supported - mbls webcam screenshot via S. Harangi

During the week of 04/19/2021 to 04/25/2021, a normal degassing of the summit craters of Etna was observed during the visibility intervals; the crater of Bocca Nuova produced frequent puffs of white vapor.

The only eruptive activity was a single, strong explosion from the east mouth of the southeastern crater, which occurred at 10:30 p.m. UTC on April 24 (12:30 a.m. local time on April 25). This explosion launched coarse glowing pyroclastic material up to 350m above the vent, which covered the entire southern slope of the cone to its base and beyond. A cloud of ash was blown south by the wind before dispersing into the atmosphere. After the explosion, no other eruptive phenomenon was observed in the southeast crater.

Etna SEC - Strombolian activity of 04.26.2021 - photo Boris Behncke

Etna SEC - Strombolian activity of 04.26.2021 - photo Boris Behncke

Etna presented two strong explosions on the night of April 24-25 and on the morning of April 26 at the Southeast Crater; the ash emissions quickly dispersed. From around 6.30 p.m., there is a slight resumption of Strombolian activity at the CSE. Activity remains modest for now.

In the evening of April 27, a slight Strombolian activity is observed at the south-eastern crater, seen from Monte Fontane on the eastern flank of the volcano, with falls of incandescent materials on the slopes.

 

Sources: INGV OE - photos by Boris Behncke

Etna SEC - Strombolian activity from 27.04.2021 in the evening - photo Boris Behncke

Etna SEC - Strombolian activity from 27.04.2021 in the evening - photo Boris Behncke

The explosions at La Soufriere in St. Vincent have greatly diminished. Seismic activity remained low with only a few long-period hybrid and volcano-tectonic earthquakes recorded and there was no sign of a tremor.

Soufriere of St. Vincent - several degassing zones and a possible lava spine -. It was noted that the tephra filled the crater so that it now reaches the top of the southwestern part of the summit. This can facilitate the exit of pyroclastic density currents from the summit crater. - photo Roderick Stewart, MVO / UWI-SRC.

Soufriere of St. Vincent - several degassing zones and a possible lava spine -. It was noted that the tephra filled the crater so that it now reaches the top of the southwestern part of the summit. This can facilitate the exit of pyroclastic density currents from the summit crater. - photo Roderick Stewart, MVO / UWI-SRC.

Signals of several lahars (mudslides) were recorded between 9 and 10 a.m. on April 27, during and after a period of rain.

The danger will continue during the hurricane season due to the possible formation of lahars due to precipitation and the abundance of ash deposits.

The volcano remains on red alert

 

Source: UWI-SRC

Soufriere of St. Vincent - field visit of 04/27/2021 - ash on dwellings and vegetation, and gullying - photo Richard Robertson, UWI-SRC.

Soufriere of St. Vincent - field visit of 04/27/2021 - ash on dwellings and vegetation, and gullying - photo Richard Robertson, UWI-SRC.

Continuous Vulcanian activity continues characterized by occasional ash emissions from the Ontake Summit Crater, on Suwanosejima, in the Ryukyu Arc.
The Japan Meteorological Agency (JMA) reported eruption plumes that rose up to 1.7 km above the crater rim and ejected bombs up to 600 m from the crater.
The incandescence of the crater was visible at night on satellite images.
The alert level remained at 2 (on a scale of 5).


Source: JMA update April 27, 2021

Suwanosejima - activity from 04/27/2021 / at 9:12 am and 7:27 pm - JMA webcam - one click to enlarge
Suwanosejima - activity from 04/27/2021 / at 9:12 am and 7:27 pm - JMA webcam - one click to enlarge

Suwanosejima - activity from 04/27/2021 / at 9:12 am and 7:27 pm - JMA webcam - one click to enlarge

Vulcanian activity continues from the summit crater of Minamidake / Sakurajima with regular eruptions at the rate of 2 per day, accompanied by ash plumes rising up to 2,400 meters above the crater and lava bombs launched at a height approximately 1 km and 1.3 km from the crater.
The seismic network has detected 11 volcano-tectonic earthquakes in the last 5 days.
The warning bulletin states that ballistic impacts from volcanic bombs and pyroclastic flows could affect an area approximately 2 km away from the main crater.

 

Source: JMA

Sakurjaima - 04/27/2021 / 6:24 am - JMA webcam

Sakurjaima - 04/27/2021 / 6:24 am - JMA webcam

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