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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

This June 4, the INGV reports a weak intracrater Strombolian activity that continues at the south-eastern crater of Etna; the lava overflow generated during the last lava fountain event cools.

In addition, intracrater explosive activity at the Bocca Nuova crater and at the same time occasional ash emissions are observed at the north-eastern crater which disperse rapidly in the summit area.
From the seismic point of view, the mean amplitude values ​​of the volcanic tremor are at a medium-high level, still showing small fluctuations. The centroid of the volcanic tremor sources remains located in the area of ​​the SE crater at an altitude of about 2900 m s.l.m.

Etna - trémor on 05.06.2021 / 06h - Doc. INGV OE

Etna - trémor on 05.06.2021 / 06h - Doc. INGV OE

Around 13:30 UTC, the images from the surveillance cameras show an increase in Strombolian activity at the level of the Southeast crater. The activity produces discontinuous ash emissions which disperse rapidly near the summit area of ​​the volcano.
From the seismic point of view, from around 13:30 UTC, it is observed that the average amplitude values ​​of the volcanic tremor are at a medium-high level showing a clear tendency to increase. The centroid of the volcanic tremor sources remains located in the SE crater area at an altitude of about 2900 m asl.

Etna SEC - 04.06.2021, respectively at 4:15 p.m., 4:30 p.m. and 4:51 p.m. - therm webcams. INGV - the 2nd circular halo is due to the setting sun - one click to enlargeEtna SEC - 04.06.2021, respectively at 4:15 p.m., 4:30 p.m. and 4:51 p.m. - therm webcams. INGV - the 2nd circular halo is due to the setting sun - one click to enlarge
Etna SEC - 04.06.2021, respectively at 4:15 p.m., 4:30 p.m. and 4:51 p.m. - therm webcams. INGV - the 2nd circular halo is due to the setting sun - one click to enlarge

Etna SEC - 04.06.2021, respectively at 4:15 p.m., 4:30 p.m. and 4:51 p.m. - therm webcams. INGV - the 2nd circular halo is due to the setting sun - one click to enlarge

From around 4:20 p.m. UTC, the passage of Strombolian activity from the Southeast crater to the lava fountain can be observed from surveillance cameras., The eruptive cloud formed by the
Lava fountain, which according to the forecast model disperses in the SE direction, reaches a height of about 6500 m above sea level.

From about 17:00 UTC, we observe a rapid decrease in the average amplitude values ​​of the volcanic tremor, which is placed at a high level with a tendency to decrease.

At around 5:30 p.m. UTC, the lava fountain in the southeast crater gradually depleted. In accordance with the forecast model, the dispersion concerned the south-eastern sector of the volcano. INGV staff in the field report the impact of the products to Aci Castello, Tremestieri and Catania (Ognina).

Etna SEC - high plume and active lava flow - photos Boris Behncke from Tremestrieri
Etna SEC - high plume and active lava flow - photos Boris Behncke from Tremestrieri

Etna SEC - high plume and active lava flow - photos Boris Behncke from Tremestrieri

In its report of 21:22 UTC, the INGV announces that the explosive activity at the Southeast crater has ceased, however the lava overflow which extends in the southwest direction; the lava flow is still fed and the flow front is located at an altitude of about 2800 m above sea level.

 

Source: INGV OE

Merapi - 06/04/2021 / 11:52 a.m. WIB - Magma Indonesia

Merapi - 06/04/2021 / 11:52 a.m. WIB - Magma Indonesia

The week of May 28 to June 3 in Merapi / Java, according to the BPPTKG weekly report

Hot cloud avalanches occurred 7 times with a maximum glide distance of 2000 m to the southwest and recorded on a seismogram with a maximum amplitude of 60 mm and a duration of 322 seconds.

Lava falls - guguran- were observed 44 times in the southwest with a maximum slide distance of 2000 meters and 1 time in the southeast with a slide distance of 600 m.

The volume of the lava dome in the southwest sector is 1,325,000 m³ with a growth rate of 11,600 m³ / day.

Merapi - the summit on 03.06.2021 - Doc. BPPTKG - one click to enlarge

Merapi - the summit on 03.06.2021 - Doc. BPPTKG - one click to enlarge

Morphological analysis of the peak area based on photos of the southeast sector from June 3 to May 28, 2021, shows that there is a difference in height of the central dome of 1 m.

The intensity of this week's earthquake is higher than last week. - The deformation of Mount Merapi, which was monitored by EDM this week, showed a distance shortening rate of 0.9 cm / day.

The alert remains at 3 / siaga

The current potential danger consists of lava avalanches and hot clouds in the South-South-West sector covering the Yellow, Boyong, Bedog, Krasak, Bebeng and Putih rivers for a maximum of 5 km and in the south-eastern sector. , the Gendol river up to 3 km.

Merapi - Pyroclastic flow on 04.06.2021 / 16:05 - photo Babada-2 - Merapi -  one click to enlarge

Merapi - Pyroclastic flow on 04.06.2021 / 16:05 - photo Babada-2 - Merapi - one click to enlarge

On June 4, 2021 at 4:05 p.m. WIB a pyroclastic flow was recorded on a seismogram with an amplitude of 50 mm and a duration of 113 seconds. hovered 1500 m to the southwest.

 

Source: BPPTKG

Fagradalsfjall - The main observation point to see the erupting crater (Gónhól) became impassable on June 4 - photo Kristín Jónsdóttir

Fagradalsfjall - The main observation point to see the erupting crater (Gónhól) became impassable on June 4 - photo Kristín Jónsdóttir

The eruption of Fagradalsfjall continues, and on May 4, 2021 at around 7 a.m., lava flows around Gónhóll and cuts the path to the observation point: the area has become an isolated island ... a new kipuka is born !.

 

On June 3, the photos of the eruptive site have silvery reflections, due to the volcanic glass.

Glass forms when magma cools rapidly and can take on many different shapes, from sparkling rocks to stringy fibers, hair, or Pele's tears.

As magma degassing faster than before, it becomes less viscous (more fluid) and therefore cools faster in interaction with air. Rapid cooling freezes the uncrystallized magma and turns into volcanic glass.

 

Sources: RUV, mbls, Kristín Jónsdóttir / IMO

Fagradalsfjall - Silver reflections on the active cone and lava field this June 3, 2021 - Screenshot RUV live via Iceland Review

Fagradalsfjall - Silver reflections on the active cone and lava field this June 3, 2021 - Screenshot RUV live via Iceland Review

Regarding the eruption at Nyiragongo, seismic data recorded on June 4 indicates a continuous decrease in the number and magnitude of earthquakes (most of them are not felt).

The GPS network of the Goma Volcanological Observatory did not detect any movement of movement of the magma below the city of Goma and Lake Kivu.

The latest satellite data recorded indicate that the ground continued to deform between May 27 and June 2.

However, the readings of the openings of the cracks measured in the city of Goma do not indicate the deformation since June 1.

New landslides are still possible in the crater and could cause ash fallout in neighboring regions.

The favorable development of the situation continues even if we cannot totally exclude a revival in activity. This justifies the continuation of intensive surveillance and the daily reassessments of the situation carried out by the OVG.

 

Sources: O.V.G, Africa Museum Georiska, & ERCC

Press release from the General Direction of the O.V.G. from 04.06.2021 - click to enlarge

Press release from the General Direction of the O.V.G. from 04.06.2021 - click to enlarge

Nyiragongo - the collapsed crater and a small deep hot spot (probably hot gases) - image Sentinel-2 bands 12,11,4 from 06/01/2021 - one click to enlarge

Nyiragongo - the collapsed crater and a small deep hot spot (probably hot gases) - image Sentinel-2 bands 12,11,4 from 06/01/2021 - one click to enlarge

Goma - report on the situation of the ERCC / European Commission of 04.06.2021 - click to enlarge

Goma - report on the situation of the ERCC / European Commission of 04.06.2021 - click to enlarge

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