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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
 Raung - light ash plume on 01.02.2021 - Doc. Magma Indonesia

Raung - light ash plume on 01.02.2021 - Doc. Magma Indonesia

On Java, a plume of gray ash is observed 500 meters above the summit of Raung.

The seismicity of February 1, 2021 is characterized by

- 31 episodes of non-harmonic tremor

- 2 local tectonic earthquakes

- 3 episodes of continuous tremor, amplitude from 1 to 18 mm, with a dominant at 5 mm.

Activity level is 2 / waspada, with a 2 km radius forbidden zone around the crater.

The VONA has been orange since February 1 at 1:50 p.m. WIB.

 

Sources: PVMBG & VAAC Darwin

Merapi - evolution of the dome in 2021- Doc. BPPTKG 01.02.2021 - one click to enlarge

Merapi - evolution of the dome in 2021- Doc. BPPTKG 01.02.2021 - one click to enlarge

BPPTKG continues to monitor the growth activity of the 2021 Merapi Lava Dome.

The volume of the lava dome reached 157,000 m³ on January 25, 2021.

On January 27, 2021, there were 52 pyroclastic flows that rolled southwest, in the upper reaches of Kali Krasak and Boyong. So far, pyroclastic avalanche flows have occurred 96 times, with the furthest sliding distance of 3.5 km.

After the pyroclastic flow of January 27, 2021, the growth rate of the lava dome 2021 was recorded at 4,000-5,000 m³ / day. The growth rate of this lava dome is relatively low compared to the average growth rate of the Mount Merapi lava dome, which is 20,000 m³ / day.

There is no change in the potential danger, which remains the pyroclastic avalanche flows in the SSO sector, with a max. of 5 km., and a danger in the event of ejection of volcanic material within a radius of 3 km.

 

Source: BPPTKG

Merapi - seismicity and displacement on February 1, 2021 - Doc. BPPTKG

Merapi - seismicity and displacement on February 1, 2021 - Doc. BPPTKG

At the Shinmoedake / Kirishima group on Kyushu Island, the JMA has seen an increase in seismicity with the epicenter below the crater, with 107 in the past 10 days of volcanic earthquakes.

No changes in inclinometer observations, but continuous GNSS observation shows an accumulation of magma in the deep part of Kirishima.

A small white plume, about sixty meters high, surmounts the crater.

The alert level is at 2 / do not approach the crater

 

Source: JMA

Shinmoedake crater - photo archives 06.11.2018 / Hayakawa Yukio

Shinmoedake crater - photo archives 06.11.2018 / Hayakawa Yukio

In Villarica, Chile, the Sernageomin reports dense white degassing at 300 - 500 m. above the summit crater on February 1.

The seismic parameters remain stable and at low levels for this volcano. The origin of the phenomenon is fundamentally atmospheric.

 

Sources Sernageomin and Volcanologia in Chile

Villarica - degassing of atmospheric origin on 01.02.2021 - photo Volcanologia en Chile

Villarica - degassing of atmospheric origin on 01.02.2021 - photo Volcanologia en Chile

January 2021 was calm at Piton de la Fournaise with only 7 superficial volcano-tectonic earthquakes recorded in one month under the summit area, and the cessation of the magma recharge of the superficial magmatic reservoir.

It should be noted that since 2016, the recharge of the superficial magmatic reservoir under the Piton de la Fournaise has been carried out by pulses, so such phases of calm in deformations and seismicity have already been observed on several occasions between 2016 and 2020 over periods ranging from 15 to 80 days approximately.

The OVPF notes 182 collapses in the Crater Dolomieu, the ramparts of the Enclos Fouqué and Piton de Crac, and the Rivière de l'Est.

The inflation (swelling) of the building which had resumed following the eruption of December 7-8, 2020 stopped at the end of December 2020. Thus during the month of January 2021 the GPS of the summit area and in the far field did not record any particular signals, with the exception of the GPNG and GPSG stations located in the Grandes Pentes area, which continued to record subsidence and eastward movement.

The GPSG station (south of the Grandes Pentes) sank approximately 22 cm and moved eastward by approximately 17 cm between October 2019 and January 2021; and the GPNG station (north of the Grandes Pentes) sank about 12 cm and moved eastwards by about 6 cm between October 2020 and January 2021.

 

Source: OVPF

Piton de La Fournaise - the eastern flank of the volcano - photo 08.2020 / OVPF

Piton de La Fournaise - the eastern flank of the volcano - photo 08.2020 / OVPF

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