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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
 Geldingadalsgos - a small eruption, but a big spectacle - photo Ragnar Axelsson 03.21.2021

Geldingadalsgos - a small eruption, but a big spectacle - photo Ragnar Axelsson 03.21.2021

The eruption in Geldingadalur is still ongoing. The activity of the lava fountain is low and the mapping of the lava flow is in progress. No volcanic ash was detected but a high level of volcanic gases was measured near the eruption site.

IMO specialists took gas measurements at the eruption site yesterday. There are indications that gas emissions from the eruption are slightly lower than the previous day, but the gas concentration near the lava flow was measured above the danger threshold.

Due to the ongoing seismic activity in the Reykjanes Peninsula, people are advised to avoid steep terrain as boulders and boulders can fall and the risk of landslides is increased.
Yesterday around 240 earthquakes were detected, the largest M3.2 just NNE of Grindavík.

Many people had to be rescued last night and overnight who tried to get to the eruption sites despite the bad weather. Photo Slysavarnafélagið Landsbjörg / mbls

Many people had to be rescued last night and overnight who tried to get to the eruption sites despite the bad weather. Photo Slysavarnafélagið Landsbjörg / mbls

An emergency arose in the area around the eruption last night due to bad weather (expected) and the fate of the occupants of five cars is still uncertain. The exhausted people had to be rescued and transported by ambulance. 38 people were taken to a first aid post in Grindavík.

By midnight it was clear that the problem was serious because at that time 140 cars were unattended, that is, people had not returned to the cars. An official search was carried out for five people and four groups, two groups of seven people and two groups of four people, for a total of 27 people.

People are still coming to the scene despite the suggestions of the rescue teams. There was sleet and strong winds in the Reykjanes Peninsula ... it was not a weather for sightseeing. "It was a serious situation up there and it is not known how it will end," Guðbrandur says, but they are trying to find out which individuals are in the cars which are still unattended.

 

Source: IMO & mbls

Piton de La Fournaise - Source of deformation model pCDM) deduced from a Bayesian inversion of the surface displacement data recorded between March 13 and March 21, 2021, in cartographic views and vertical sections. The color level indicates the maximum probability level combined with the volume change sign (yellow-orange-red for inflation, green-cyan-blue for deflation). The black, red and green arrows are respectively the observed displacements, the modeled displacements and the residuals. Ellipses represent errors. The best model is indicated in the form of yellow plans (© OVPF-IPGP).

Piton de La Fournaise - Source of deformation model pCDM) deduced from a Bayesian inversion of the surface displacement data recorded between March 13 and March 21, 2021, in cartographic views and vertical sections. The color level indicates the maximum probability level combined with the volume change sign (yellow-orange-red for inflation, green-cyan-blue for deflation). The black, red and green arrows are respectively the observed displacements, the modeled displacements and the residuals. Ellipses represent errors. The best model is indicated in the form of yellow plans (© OVPF-IPGP).

Following the resumption of seismicity on March 13 under the Piton de la Fournaise, it continues. Thus between March 13 and March 21, 90 volcano-tectonic earthquakes, of magnitude between <1 and 1.8, were recorded and located under the Dolomieu crater between 0.2 and 0.9 km above the level of the sea ​​(ie between 1.6 and 2.3 deep).

This seismicity is accompanied by a resumption of inflation in the building. The source at the origin of this inflation is located about 2 km deep under the Dolomieu crater, at the level of the superficial magmatic reservoir.

Piton de La Fournaise - number of superficial volcano-tectonic earthquakes recorded between January 1 and March 21, 2021 (© OVPF-IPGP).

 

The CO2 fluxes in the ground are still increasing, especially on the sides of the volcano in the far field (Plaine des Cafres and Plaine des Palmistes sectors). Since CO2 is the first gas to be released from magma at great depth (from the mantle), its detection in the far field is often associated with a deep rise of magma.

This deep rise of magma is at the origin of the pressurization of the superficial magmatic reservoir, and the seismicity and inflation associated with it.

This recharging process from the depths to the shallow reservoir can take several days to several weeks before the reservoir roof weakens and breaks, resulting in an injection of magma to the surface and an eruption, but can also stop without giving rise to an eruption in the short term.

Current alert level: Vigilance

 

Source: Bulletin of the Volcanological Observatory of Piton de la Fournaise from 22/03/2021 - 10: 00 local time

Find all the information relating to the activity of Piton de la Fournaise on the various media of the OVPF-IPGP:

- Internet (http://www.ipgp.fr/fr/ovpf/actualites-ovpf),
- Twitter (https://twitter.com/obsfournaise?lang=fr),
- Facebook (https://www.facebook.com/ObsVolcanoPitonFournaise/)

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