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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

I resume the paroxysm of Etna of April 1 where I left it at the end of writing yesterday.

From approximately 11:20 UTC, the decrease in explosive activity at the SE crater is observed. Due to the cloud cover, the observation of the current activity from the surveillance cameras is very limited and discontinuous, but the lava flows and the
the first lava overflow, which took place in the Valle del Bove, and the second overflow, which reached the eastern base of the SE crater, appear to be less fueled than previously reported. The cloud cover does not currently allow any observation of the lava flows which have spread to the SW, S and ESS.

Etna SEC - activity at dawn on April 1, 2021 - photo Gio Giusa

Etna SEC - activity at dawn on April 1, 2021 - photo Gio Giusa

At 11:00 UTC, INGV staff reported a lapilli of about 1 cm in Rifugio Sapienza and a thin layer of ash in Nicolosi and Catania.

At around 11:20 UTC, the decrease in explosive activity at the SE crater was observed. Due to the cloud cover, the observation of the current activity from the surveillance cameras is very limited and discontinuous, but the lava flows and the
the first lava overflow, which took place in the Valle del Bove, and the second overflow, which reached the eastern base of the SE crater, appear to be less fueled than previously reported. The cloud cover does not currently allow any observation of the lava flows which have spread to the SW, S and ESS.
INGV staff on the ground this morning confirms that the front of the SW lava flow is about 2,600 m above sea level. and that the SSE flow front also reached an elevation of approximately 2600 m. at the time of observation.

Etna SEC - activity at dawn on April 1, 2021 - photo Gio Giusa

Etna SEC - activity at dawn on April 1, 2021 - photo Gio Giusa

From around 13:50 UTC, improving weather conditions made it possible to observe, through surveillance cameras, that the SSE lava flow reached and crossed the western edge of the Valle del Bove. For the moment, the forehead is
is located at an altitude of approximately 2300 m asl. In addition, in the distal zone, the SE lava flow still seems to be fed by the front which is around 1900 m asl, while the two lava overflows, which originated from the eastern edge of the SE Crater, appear in cooling.

Etna SEC - 04/01/2021 / 4:54 p.m. - INGV OE webcam Emct0318

Etna SEC - 04/01/2021 / 4:54 p.m. - INGV OE webcam Emct0318

In its 9:37 p.m. report, the INGV reports from surveillance cameras, it is observed that the lava flows that took place in the upper western sector of the Valle del Bove (at least three main ones can be distinguished) seem less fed by the fronts which are located between approximately 2100 m and 1700 m of altitude.
In addition, still on the western edge of the Valle del Bove, there are thermal anomalies probably attributable to the fronts of other lava flows which have not yet overflowed from the edge and therefore remain confined to an altitude of around 2700 m. above sea level.
The lava overflows from the eastern edge of the SE crater cool down further, mainly blocks are observed which, standing out from the fronts, roll towards the Valle del Bove. Finally, the flow that has developed in the SW direction no longer appears
powered and cooled. From the surveillance cameras, no explosive activity was observed at the SE crater; the intracrater activity at the NE and BN crater remains, and the intracrater explosive activity of the Voragine crater which generates discontinuous ash emissions which are rapidly dispersed in the summit area.

 

Source: INGV OE

Sinabung - seismicity on April 1, 2021 - Doc. Magma Indonesia

Sinabung - seismicity on April 1, 2021 - Doc. Magma Indonesia

In Sinabung, this April 1, an eruption was observed 500 meters above the summit, accompanied by a plume of ash and gray gas. Pyroclastic avalanche flows were observed with a sliding distance of 1500 meters to the east and south-east. Avalanches of incandescent blocks were observed with a sliding distance of 1000 meters from the summit with the direction of the slide from east to south-east.

The seismicity of April 1 is characterized by:

- 1 eruption earthquake
- 1 earthquake related to a pyroclastic flow
- 53 collapse / avalanche earthquakes
- 3 blast / emission earthquakes
- 7 hybrid / multiphase earthquakes
- 2 distant tectonic earthquakes.

The activity level remains at 3 / siaga, with the usual prohibited areas.

 

Sources: PVMBG, Magma Indonesia

Sinabung - the dome on 04.02.2021 / 5.30am, photographed by Sukanalu Teran - photo Sadrah Peranginangin

Sinabung - the dome on 04.02.2021 / 5.30am, photographed by Sukanalu Teran - photo Sadrah Peranginangin

Sinabung - Strombolian activity on 04/02/2021 around 5:30 am - photo Sadrah Peranginangin

Sinabung - Strombolian activity on 04/02/2021 around 5:30 am - photo Sadrah Peranginangin

The activity of Ili Lewotolok, on Lembata, in level 3 / siaga, remains high, with this April 1:

- 4 eruption earthquakes
- 46 emission earthquakes
- 35 episodes of non-harmonic tremor
- continuous tremor, amplitude 0.5-2 mm (dominant 0.5 mm)
- 1 local tectonic earthquake

Communities around Mount Ili Lewotolok as well as visitors / climbers / tourists are recommended not to undertake any activities within 3 km of the summit / crater of Mount Ili Lewotolok. Residents of Jontona village should always be aware of the potential danger of landslides of weathered material which may be accompanied by hot clouds originating from the southeastern part of the summit / crater of Mount Ili Lewotolok.

 

Source: PVMBG

Ili Lewotolok - sentinel-1 SAR image from 04/01/2021 / 9:20 p.m. - via Mounts project

Ili Lewotolok - sentinel-1 SAR image from 04/01/2021 / 9:20 p.m. - via Mounts project

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