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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
Reunion / Piton de La Fournaise - Dolomieu and Bory craters - photo archives © Bernard Duyck

Reunion / Piton de La Fournaise - Dolomieu and Bory craters - photo archives © Bernard Duyck

The seismic crisis that began at 4:33 am local time (12:33 am UTC) at Piton de La Fournaise gradually subsided this morning.

This morning, only rare earthquakes are still recorded and their location remains confined to the Plaine des Osmondes sector to the west-northwest of Piton de Crac.

A total of 679 volcano-tectonic earthquakes, and 241 long-period and deep-type earthquakes were recorded by the OVPF between 10/18/2021 and 10/19/2021 at 8 a.m. local time. This seismicity was localized under the summit area and under the northeast flank (between 0.7 km above sea level and 1.4 km below sea level.

The alert level is at 1

 

Update : in its 14:30 press release, the OVPF declares that the seismic crisis has stopped. The intrusion that has taken place in the Plaine des Osmondes no longer seems to be progressing today. Apart from a Magnitude M1.9 earthquake at 10:51 (local time) located 1.4 km below sea level, no Magnitude M> or = 0.5 earthquake has been recorded today by the OVPF , whether under the summit or in the Plaine des Osmondes.

Despite the end of the seismic crisis and the cessation of the deep intrusion, a resumption of the progress of the intrusion further downstream or in another area is not excluded.

 

Source : OVPF

Piton de La Fournaise: Location map (epicenters) and north-south and east-west sections (showing the location in depth, hypocenters) of the earthquakes recorded and located by the OVPF-IPGP between 10/18/2021 and 19 / 10/2021 8h under the Piton de la Fournaise massif. Only a few characteristic earthquakes have been located at this time (© OVPF-IPGP)

Piton de La Fournaise: Location map (epicenters) and north-south and east-west sections (showing the location in depth, hypocenters) of the earthquakes recorded and located by the OVPF-IPGP between 10/18/2021 and 19 / 10/2021 8h under the Piton de la Fournaise massif. Only a few characteristic earthquakes have been located at this time (© OVPF-IPGP)

Vedurstofan has lowered the aviation alert (aviation color code) from orange to yellow for the Krísuvík volcanic system - Fagradalsfjall / Geldingadalur eruption.

From September 18 to the present day, no lava flow has been observed from Fagrdalsfjall crater. Gas is still measured, but in very small quantities, signs of temperature are also visible, but at longer intervals. Every now and then there is glowing lava from the previous outing and especially when it's dark. The heat and embers can continue for weeks / months even if no new lava comes out of the crater. Seismic activity southwest of Keilir, which began on September 27, has declined significantly in recent days.

No rash has been observed for an entire month

 

Sources: Kristín Jónsdóttir / IMO & Icelandic volcanoes

Trouble graph showing activity from September 18 to October 18 around the Fagradalsfjall eruption - Doc. IMO

Trouble graph showing activity from September 18 to October 18 around the Fagradalsfjall eruption - Doc. IMO

In La Palma, the eruption of Cumbre Vieja continues, the lava flows mainly concern the northern flank, and progress in a west-north-west direction.

A flow channel is 160 meters from the sea; its speed slowed down to about 2 m./hour.The height of the plume of gas and ash is about 4,200 meters

After a month of eruption, the affected area reached 763 hectares. Copernicus reports 1956 destroyed buildings.

Two educational centers were closed in the Tazacorte area, given the possibility of lava reaching the coast.

LaPalma Cumbre Vieja - This photograph taken by IGME staff - CSIC shows three of the four mouths that are active at this time in the Volcano de La Palma, as well as the large accumulation of ash in the surrounding areas

LaPalma Cumbre Vieja - This photograph taken by IGME staff - CSIC shows three of the four mouths that are active at this time in the Volcano de La Palma, as well as the large accumulation of ash in the surrounding areas

La Palma / Cumbre Vieja - the castings at 17.10.2021 / 18:56 - Doc. Copernicus EMSR

La Palma / Cumbre Vieja - the castings at 17.10.2021 / 18:56 - Doc. Copernicus EMSR

Since the last declaration, 101 earthquakes have been located in the area affected by the volcanic reactivation of Cumbre Vieja, 7 of these earthquakes were felt by the population, the maximum intensity being in the epicentral zone IV (EMS98) , in the earthquakes that occurred at 11:06 am and 11:57 pm UTC on the 17th, with magnitudes of 4.0 and 4.6 (mbLg) at depths of 35 and 36 km, respectively. Moreover, this last earthquake was the most important of the period under consideration.
A total of 35 earthquakes were located at depths of about 30 km, the rest of the hypocenters of the period are located at a shallower depth of about 12 km.
The volcanic tremor signal maintains a high average amplitude, with intensifying pulses, since the last communication.

 

Sources: InVolcan de Canarias, GEVolcan IGME, DSN, IGNSpain

La Palma - Seismicity at 18.10.2021 / 12:06 - Doc. IGNes

La Palma - Seismicity at 18.10.2021 / 12:06 - Doc. IGNes

In the Ogasawara Islands, an activity still marks Nishinoshima and Fukutoku Okanoba, revealed by the discoloration of the waters around these volcanoes.

On October 17, crustal movements brought up sunken shipwrecks.

 

Source: ANNnewsCH & Japan Coast Guards Video

Nishinoshima - 12.10.2021 - by Japan Coast Guards

Nishinoshima - 12.10.2021 - by Japan Coast Guards

Fukutoku - discolored waters surrounding the Niijima - photo JCG

Fukutoku - discolored waters surrounding the Niijima - photo JCG

ANNnewsCH video - from Nishinoshima to Fukutoku

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