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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

After the intense activity of this Saturday, eruptive episodes followed at Semeru on December 5 and 6, 2021:

- the first, this Sunday December 5, 2021 at 10:08 a.m. WIB was recorded on a seismograph with a maximum amplitude of 37 mm and a duration of 6600 seconds. No visual rash was observed.
- A second was observed Sunday at 05:03 WIB with the height of the ash column at ± 500 m above the summit (± 4176 m above sea level). We observe that the ash column is white with a thick intensity towards the north and south-east. This eruption was recorded on a seismograph with a maximum amplitude of 10 mm and a duration of 201 seconds.

Semeru - Pyroclastic flow on 06.12.2021 / 08h55 - screenshot Magma Indonesia - one click to enlarge

Semeru - Pyroclastic flow on 06.12.2021 / 08h55 - screenshot Magma Indonesia - one click to enlarge

- This Monday, December 6, 2021 at 07:53 WIB an eruptive episode was recorded on a seismograph with a maximum amplitude of 24 mm and a duration of 240 seconds. No visual rash was observed.
- A second followed this December 6, 2021 at 08:55 WIB. No visual rash was observed. This eruption was recorded on a seismograph with a maximum amplitude of 22 mm and a duration of 480 seconds.

 

The Vona remains red; According to VAAC Darwin, the ashes could not be identified by satellite, due to my cloud cover. The pyroclastic flows continue according to observers on the ground.

The activity level remains at 2 / waspada.

 

Sources : Magma Indonesia &VAAC Darwin

Semeru - desolation in areas affected by ash and lahars - photos 05.12.2021 SAR Prov Jatim
Semeru - desolation in areas affected by ash and lahars - photos 05.12.2021 SAR Prov Jatim

Semeru - desolation in areas affected by ash and lahars - photos 05.12.2021 SAR Prov Jatim

The INGV OE reports to on December 4 09:55 loc. sporadic and diluted ash emissions from the south-eastern crater of Etna. Due to cloud cover, observations are made discontinuously. From the seismic point, the tremor increases slightly on the average values. The infrasonic activity is at low levels and does not show significant changes.

Strombolian activity is observed at the southeast crater from 4:10 p.m. GMT.
From the seismic point of view, the gradual increase in the amplitude of the tremor continues. An increase in infrasound activity is also observed from 3 p.m.

 

Strombolian activity continued at the southeast crater during the day on December 5. The activity produced some sporadic ash emissions scattered around the summit area. At dusk, a few glimmers are observed in the clouds, but due to the presence of dense cloud cover in the summit area, it was not possible to assess the intensity and frequency of the explosions.
The amplitude of the tremor is stable on average values ​​and its location remains close to the south-eastern crater.

 

Source: INGV OE

Etna SEC - 04.12.2021 in the evening - photo Boris Behncke

Etna SEC - 04.12.2021 in the evening - photo Boris Behncke

As of 12.05.2021 10h UTC, a total of 36 earthquakes have been located in the area affected by the volcanic reactivation of Cumbre Vieja on the island of La Palma, none of them were felt by the population.
Seismicity continues below the central area of ​​Cumbre Vieja in the same areas of the previous days, 33 of these earthquakes are located at depths of 9 to 17 km and only 3 at depths greater than 34 km. The maximum recorded magnitude is 3.4 (mbLg) corresponding to two earthquakes yesterday, at 12:19 UTC and 14:48 UTC, with depths of 36 km and 13 km respectively.
The amplitude of the tremor signal remains weak and more stable than the previous days.

La Palma - seismicity at 12/05/2021 / 10:32 a.m. - doc. IGN

La Palma - seismicity at 12/05/2021 / 10:32 a.m. - doc. IGN

La Palma - Cumbre Vieja - Photo IGN 05.12.2021

La Palma - Cumbre Vieja - Photo IGN 05.12.2021

The lava emission continues, produced by new cracks that have opened to the west of Montaña Cogote, affecting a new surface of dwellings in an area already evacuated. A total of 9 vents and two major fissures have been more or less active since December 4 in this southern area.

Strombolian activity is noted in the late afternoon at the northern mouth. Note that large cracks have opened in the main cone.

In view of the image calibrated at 08:45 UTC, a degassing cloud height of 1400 m is estimated.
The height of the cone is measured by obtaining a value of 1,124 m. asl.

 

The surface covered by the lava flows on December 4 was 1,154 ha, for a max. of 3,350 meters and that of the lava delta of 48.03 ha.

Regarding the air quality due to sulfur dioxide (SO2), yesterday the levels remained between reasonably good and regular in almost all the stations of the island.

 

Sources: IGN, IGME, DSN, Copernicus, Volcanes y Ciencias hoy, RTVC

La Palma Cumbre Vieja - large cracks in the main cone this 05.12.2021 - IGME photo

La Palma Cumbre Vieja - large cracks in the main cone this 05.12.2021 - IGME photo

According to the latest measurements taken on December 4, 2021 between 9:40 am and 12:30 pm, the flow at Gígjukvísl is 2220 m3 / s and the electrical conductivity is now measured at 550µS / cm. These measurements are in line with the flow forecasts that have been made and the flood is expected to peak again tomorrow Sunday. If there are major changes in the development of the Grímsvötn flow, this will affect when the flood peak is reached. Hlaupórói continues to grow on Grímsfjall and neighboring stations and several earthquakes have been detected in the area, some of them probably originated in the ice above the lakes, or where water flows. The area is closely watched.

Flow measurements show that the maximum flow from Grímsvötn was on December 5 by noon and since then the flow to Gígjukvísl has decreased somewhat.

 

A magnitude 3 earthquake rocked Grímsvötn around 6 a.m. this morning. The earthquake originated about a kilometer and a half northeast of Grímsfjall at a depth of about 100 meters.
Bjarki Kaldalón Friis, nature conservation expert at the Meteorological Office, says it's hard to say whether the earthquake is related to the ice cave subsidence. There are no signs of rashes so far. Several smaller earthquakes were detected after and just before the larger one.

Update : A change has been made to the flight color code for Grímsvötn. The color code changed from yellow to orange By definition, the flight color code changes to orange when a volcano shows increased activity and there is an increasing likelihood of an eruption.

 

Sources: IMO & Iceland Univ.

Grimstvötn - discharge on 06.12.2021 / 05.59 am - Doc. Iceland Univ & IMO

Grimstvötn - discharge on 06.12.2021 / 05.59 am - Doc. Iceland Univ & IMO

Vatnajökull / Grimstvötn - location and magnitude of earthquakes - Doc. IMO 12/06/2021 / 7:45 a.m.
Vatnajökull / Grimstvötn - location and magnitude of earthquakes - Doc. IMO 12/06/2021 / 7:45 a.m.
Vatnajökull / Grimstvötn - location and magnitude of earthquakes - Doc. IMO 12/06/2021 / 7:45 a.m.

Vatnajökull / Grimstvötn - location and magnitude of earthquakes - Doc. IMO 12/06/2021 / 7:45 a.m.

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