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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

Before noon on March 28, 2021, the two craters of the volcano in Geldingadalur began to change their morphology somewhat. The craters have been given nicknames and the highest is called the south and the lower north. The flow of this through a southwest facing breach merged with the flow in the southern channel to the side of the lava rivers. This could be the first step in the union of the craters.
 

Lava that has formed over the Geldingadalur craters over the past nine days has now covered the valley floor. There are three to seven million cubic meters of lava rising from the earth, which may seem less on another scale as it is 0.003 to 0.007 cubic kilometers. The lava flow increases rather than decreases. This is one of the conclusions of a summary by the Volcano and Nature Conservation group at the University of Iceland, which was published this morning.

Geldingadalgos - 03.28.2021 - morphology change around 11:50 am - RUV webcam

Geldingadalgos - 03.28.2021 - morphology change around 11:50 am - RUV webcam

Besides an explosion and a small plume of brown ash around 4:25 p.m., many people noticed beautiful pyrocumulus, visible as far as Reykjavik.

"In Geldingadalur, we have lava that is 800 to 1200 degrees; it constantly heats the atmosphere above the lava, and creates such a rise in ambient humidity to form a beautiful cloud," says Elín Björk Jónasdóttir, meteorologist at the Icelandic meteorological office.

Geldingadalgos - small plume of brown ash on 03/28/2021 at 4:21 p.m. - RUV webcam

Geldingadalgos - small plume of brown ash on 03/28/2021 at 4:21 p.m. - RUV webcam

Reykjanes Peninsula - 03.28.2021 / 6pm approximately - A "Pyrocumulus" above the eruptive site seen from Reykjavik - photo Dr. Evgenia Ilynskaya

Reykjanes Peninsula - 03.28.2021 / 6pm approximately - A "Pyrocumulus" above the eruptive site seen from Reykjavik - photo Dr. Evgenia Ilynskaya

Geldingadalgos - 03.28.2021 / 8:21 p.m. - 2 active lava fountains, a flow feeding the lava field - RUV webcam

Geldingadalgos - 03.28.2021 / 8:21 p.m. - 2 active lava fountains, a flow feeding the lava field - RUV webcam

American scientists have built a lava flow simulator and their hypothesis is that if it continues to erupt, the lava will flow south to Nátthaga. The edge of the lava field at Geldingadalur has slowed the spread of lava and the lava can recharge so that it is higher than the edge ... the containment can then suddenly give way and a sudden overflow is possible.

The popularity of the eruption has not waned and many traveled to Geldingadalur today. Two car parks have been put into operation at Suðurstrandavegur. A section had to close today, due to an overflow. It has been decided to close Geldingadalur this evening at nine o'clock; visitors should exit the area by midnight. This was done to rest the rescue team which has been on duty for over a week.

Suðurstandarvegur is closed and no one should enter the region any more, before the situation is reviewed.

 

Sources : IMO, RUV, mbls, Óróapúls and Police du Suðurnes

Geldingadalgos - 03.29.2021 / around 8am - east webcam mbls

Geldingadalgos - 03.29.2021 / around 8am - east webcam mbls

Krisuvik - thermal anomalies at 03/29/2021 2:55 a.m. - Doc. Mirova

Krisuvik - thermal anomalies at 03/29/2021 2:55 a.m. - Doc. Mirova

After an increase in seismicity from March 22 to 26, 2021 at Piton de La Fournaise, with a number of earthquakes peaking at 95 on March 26, the daily number of earthquakes is decreasing, with on March 27 and 28 respectively : 55 and 8 earthquakes .

The OVPF points out that during the recharge phases, the rate of seismicity can be erratic. A rapid increase in seismicity may be linked to a destabilization of the hydrothermal system located under the summit, due to the rise of magma.

Piton de La Fournaise - Histogram representing the number of superficial volcano-tectonic earthquakes recorded between January 1 and March 28, 2021 (© OVPF-IPGP).

Piton de La Fournaise - Histogram representing the number of superficial volcano-tectonic earthquakes recorded between January 1 and March 28, 2021 (© OVPF-IPGP).

Inflation continues on the other hand; with a source located between 1,500 and 2,000 meters below the Dolomieu crater, at the level of the superficial magmatic reservoir.

The composition of the fumaroles at the top shows a "hydrothermal type" composition, dominated by water and H2S, with low amounts of SO2 and CO2. Sulfur dioxide flows are decreasing around the perimeter of the Enclosure.

The process of recharging the surface reservoir continues ... to be continued.

 

Source: OVPF

Dolomieu crater of Piton de La Fournaise - photo archives © Bernard Duyck

Dolomieu crater of Piton de La Fournaise - photo archives © Bernard Duyck

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