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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
Nevados de Chillán - morphological changes of the L5 lava flow - Doc. Sernageomin

Nevados de Chillán - morphological changes of the L5 lava flow - Doc. Sernageomin

An explosive and effusive activity continued during this fortnight at the Nevados de Chillán complex.

Explosive events are characterized by the generation of eruptive columns smaller than 1,420 m above the crater level, with varying content of particulate matter.

Night incandescence is observed recurrently, mainly in the eastern area of ​​the crater and sometimes on the lava flow.

Regarding effusive activity at the level of the L5 lava flow, according to the analysis of SkySat, Planet Scope and Sentinel L2 A satellite images in true color, a range of the lava front, estimated at 808 m. from the rim of the crater, with further development of its central channel, rose by at least 40 m. wide in its proximal area.

Thanks to surveillance cameras, an acceleration of its emission rate is recorded, accompanied by a change in the forward dynamics of the forehead, the morphology of the lateral "levees" and the incipient development of lateral lobes in the proximal zone of the forehead. crater. The sum of these results is interpreted as a change in the rheology of the L5 lava flow.

 

Source: Sernageomin

Sabancaya - simultaneous plumes of steam and gas, and ash - Doc. I.G. Peru

Sabancaya - simultaneous plumes of steam and gas, and ash - Doc. I.G. Peru

Between February 1 and 7, 2021, the eruptive activity of Sabancaya was maintained at moderate levels, with an average of 45 daily explosions, and the observation of ash and gas plumes up to 3,000 meters high. above the summit.

I.G. Peru provides information on the occurrence of 1,548 earthquakes of volcanic origin, associated with the circulation of internal magmatic fluids. Volcano-tectonic earthquakes, related to the fracturing of rocks inside the volcano, occurred mainly in the northeast of Sabancaya (magnitude between 2.2 and 2.7)

A slight inflation of the south-eastern sector of Sabancaya and of the northern sector / Hualca Hualca volcano was observed thanks to the GNSS technique. Two weak thermal anomalies were identified by Mirova.

Note: the descent of a lahar on February 4 on the south-eastern flank.

 

The volcanic alert remains Naranja, with a forbidden zone with a radius of 12 km, and the advice to stay away from the drainages.

 

Source: IGP bulletin posted on February 8, 2021.

Montserrat - Soufrière Hills - General view looking south into the 2010 collapse scar on the north side of the lava dome - MVO photo

Montserrat - Soufrière Hills - General view looking south into the 2010 collapse scar on the north side of the lava dome - MVO photo

A good visibility on the lava dome of the Soufriere Hills volcano on the island of Montserrat, in the Caribbean, on January 29 and February 2 allowed various fumaroles to be imaged using the portable thermal camera, giving temperatures included between 212 and 472 ° C. These are consistent with previous temperatures measured in December 2020.

Visual observations from the helicopter also revealed evidence of continued rockfall activity under all steep faces of the lava dome, particularly inside the 2010 collapse scar and at the head of Gage Fan on the west side of the Lava Dome. Three large slabs have also been observed to form in the cliff wall on the Tar River side of the lava dome, which could lead to large rockfall in the future.

This is part of the natural process of weathering and loss of mass and does not imply a decrease in the stability of the lava dome.

Montserrat - Soufrière Hills - Close-up view of the main fumarole (aka Gas Vent) in the floor of the 2010 collapse scar, with a thermal image showing temperatures above 415 ° C. - photo MVO 29.01.2021

Montserrat - Soufrière Hills - Close-up view of the main fumarole (aka Gas Vent) in the floor of the 2010 collapse scar, with a thermal image showing temperatures above 415 ° C. - photo MVO 29.01.2021

Montserrat - Soufrière Hills - General view looking south into the 2010 collapse scar on the north side of the lava dome - MVO photo 01.29.2021

Montserrat - Soufrière Hills - General view looking south into the 2010 collapse scar on the north side of the lava dome - MVO photo 01.29.2021

Due to the large size of the lava dome, pyroclastic flows can occur at any time without warning from any side of the volcano, including drainages ("Gages") through which they can quickly reach Plymouth.

Trails through the Belham Valley can be destroyed or greatly altered by flash floods or lahars, and caution should be exercised crossing the valley during and after rains.

The danger level is 1. There is no public access to Zone V, including Plymouth. Sea zones E and W are in daytime transit only between sunrise and sunset (boats can pass through the zone but should not stop). Anyone who ignores these restrictions is liable to prosecution.

 

Source: MVO

Kilauea - Halema'uma'u - the western vent supplying the active western part of the lava lake, as well as the inactive eastern part of the lava lake. There are a few small pāhoehoe lava eruptions in the western part of the lava lake that sometimes overflow into the hilltop part of the lava lake margin. - USGS Photo by D. Downs / 02.08.2021.

Kilauea - Halema'uma'u - the western vent supplying the active western part of the lava lake, as well as the inactive eastern part of the lava lake. There are a few small pāhoehoe lava eruptions in the western part of the lava lake that sometimes overflow into the hilltop part of the lava lake margin. - USGS Photo by D. Downs / 02.08.2021.

Kilauea - Helema'uma'u - The active western side of the lake exhibited numerous surface eruptions and a dark crust. Lava effusion continues into the lava lake from the base of the west vent (left). USGS photo taken by K. Lynn.

Kilauea - Helema'uma'u - The active western side of the lake exhibited numerous surface eruptions and a dark crust. Lava effusion continues into the lava lake from the base of the west vent (left). USGS photo taken by K. Lynn.

The Kīlauea volcano is erupting. Lava activity is confined to Halemaʻumaʻu crater.

Eruptive activity continues at the western fissure, supplying lava to the lava lake via a lava stream at the entry site along the western margin. Yesterday, HVO geologists reported a small active dome fountain at the entrance site. The active surface lava remains largely confined to the western half of the lake, as before. The western part of the lake continues to present scattered crustal shipwrecks. The stagnant eastern part of the lake was several meters lower than the perched, elevated and active western part. A series of surface cracks separate the asset from the stagnant part of the lake. The islands remained stationary last week.

As of the morning of February 9, the lava in the western and active part of Halema'uma'u Lake was about 215 m (705 feet) deep, with the eastern part of the lava lake solidifying on the surface. SO2 emission rates remain high.

 

Source: HVO-USGS

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