Overblog
Editer l'article Suivre ce blog Administration + Créer mon blog

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 Etna, last evening January 28, 2021, a few moments of partial visibility between these encrusted clouds made it possible to observe an activity at the Southeast Crater a little less intense than the previous days (in concert with an amplitude of the lowest volcanic earthquake), but we still see the two eastern mouths and sometimes even that "of the saddle", as well as frequent small explosions with the Voragine and a continuous glow indicative of a new flow of lava which is flows from this crater into the adjoining Bocca Nuova.

Etna - activité des cratères sommitaux le 28.01.2021 en soirée - photo Boris Behncke

Etna - activité des cratères sommitaux le 28.01.2021 en soirée - photo Boris Behncke

Etna SEC - activity on 01.28.2021, at 6:22 p.m., 7:28 p.m. and 8:27 p.m. respectively - LAVE webcam - one click to enlarge
Etna SEC - activity on 01.28.2021, at 6:22 p.m., 7:28 p.m. and 8:27 p.m. respectively - LAVE webcam - one click to enlargeEtna SEC - activity on 01.28.2021, at 6:22 p.m., 7:28 p.m. and 8:27 p.m. respectively - LAVE webcam - one click to enlarge

Etna SEC - activity on 01.28.2021, at 6:22 p.m., 7:28 p.m. and 8:27 p.m. respectively - LAVE webcam - one click to enlarge

Etna- trémor at 01.29.2021 / 02:10 - Doc. INGV

Etna- trémor at 01.29.2021 / 02:10 - Doc. INGV

At Etna, the "boati " who are feeling lately are not a sign of danger, they are not evidence of strange things in depth, and are not even signs of particularly violent eruptive events.

These are totally superficial phenomena, generated by contact between the exploding magma and the atmosphere. The rapid decompression of a large gas bubble at the top of the magmatic column in the duct produces a shock wave in the atmosphere, the infrasonic part of which - that is, the acoustic signal at very low frequency, between 0 and 20 Hertz, not audible to human ear - shakes everything. It doesn't take a giant explosion to do this, but it's how the explosion happens, the rate of energy release, that determines how strongly the "boato" and infrasonic wave feel.

The only problem with these "boati ": when they occur at night, they can disrupt sleep.

 

Sources: INGV OE & Boris Behncke

Sinabung - 01.29.2021 / 8:06 am - photo Nachelle homestay

Sinabung - 01.29.2021 / 8:06 am - photo Nachelle homestay

At Sinabung, the main crater has a thick, white plume about 200 to 500 meters from the summit.

In terms of seismicity, there has been an increase in recent days; this January 29 between 6 and 12h, we count:

- 20 earthquakes of collapse / avalanche, with an amplitude of 2 to 115 mm lasting 22 to 383 sec.

- 4 earthquakes of blast / emission

- 8 hybrid multiphase earthquakes

- 1 distant tectonic earthquake.

 

Sources: PVMBG, Magma Indonesia

Sinabung - seismicity as of 01/28/2021; to note an increase in the number of earthquakes these last days - Doc. Magma Indonesia

Sinabung - seismicity as of 01/28/2021; to note an increase in the number of earthquakes these last days - Doc. Magma Indonesia

At Merapi, an aerial overflight allowed to determine the displacement distance of the pyroclastic flows of January 27, 2021: 3,500 meters on the slope.

A cloud-free top shows the partial destruction of the dome, and the morphological changes that surround it.

The rains remobilized the ashes and caused a lahar in the Boyong River.

 

The seismicity of January 28 breaks down in :

- 1 earthquake accompanying a pyroclatic flow, with an amplitude of 69 mm for 175 sec., And an estimated displacement of 2,000 meters towards the south-west. (Kali Krasak & Boyong)

- 139 collapse / avalanche earthquakes

- 8 blast / emission earthquakes

- 14 multiphase hybrid earthquakes

 

Sources: PVMBG, Magma Indonesia, BPPTKG

Merapi - Co-pyroclastic cloud of 01.28.2021 / 10:13 WIB

Merapi - Co-pyroclastic cloud of 01.28.2021 / 10:13 WIB

Merapi - lahar along the Boyong river  - photoMerapi uncover 29.01.2021

Merapi - lahar along the Boyong river - photoMerapi uncover 29.01.2021

Merapi - 01.28.2021 - morphological changes around the dome - photo Frekom & SAR Kaliurang
Merapi - 01.28.2021 - morphological changes around the dome - photo Frekom & SAR Kaliurang

Merapi - 01.28.2021 - morphological changes around the dome - photo Frekom & SAR Kaliurang

A moderate explosive-effusive eruption of the volcano continues at Klyuchevskoy.

According to video and satellite data, a gas-steam plume with a certain amount of ash extends 92 km east of the volcano, and at 5,800+ 6,000 meters on January 29, 2021.

The aviation code remains orange, other explosions may affect air traffic.

 

Sources: KVERT, Mirova and VAAC Tokyo

Klyuchevskoy - 01.29.2021 / 08:19 - IVS FEB RAS KVERT webcam

Klyuchevskoy - 01.29.2021 / 08:19 - IVS FEB RAS KVERT webcam

Klyuchevskoy - thermal anomalies at 01.29.2021 / 00h31 - Doc. Sentinel 2 - MIROVA_Last

Klyuchevskoy - thermal anomalies at 01.29.2021 / 00h31 - Doc. Sentinel 2 - MIROVA_Last

Commenter cet article

Articles récents

Hébergé par Overblog