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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
La Palma, eruption of Cumbre Vieja - photo of the oceanographic vessel Ramon Margalef - Eugenio Fraile Oceanographer 25.09.2021

La Palma, eruption of Cumbre Vieja - photo of the oceanographic vessel Ramon Margalef - Eugenio Fraile Oceanographer 25.09.2021

Images taken by IGEM using a drone, on September 25, show four vents at the Cumbre Vieja eruptive site, including three in the crater of the cone and one at the outer base of it.

Two flows are active: the northern lava flow, more fluid, flows over older lava, the southern flow, slower, moves in virgin land.

La Palma, Cumbre Vieja - the eruptive site at 09.26.2021 / 11 a.m. loc. - photo InVolcan - one click to enlarge

La Palma, Cumbre Vieja - the eruptive site at 09.26.2021 / 11 a.m. loc. - photo InVolcan - one click to enlarge

La Palma, Cumbre Vieja - a clearing allowed to see the flows of 26.009.2021 / 11:42 UTC - image Sat.Landsat 8 - Annamaria Luongo / Twitter - one click to enlarge

La Palma, Cumbre Vieja - a clearing allowed to see the flows of 26.009.2021 / 11:42 UTC - image Sat.Landsat 8 - Annamaria Luongo / Twitter - one click to enlarge

Eruption of Cumbre Vieja - Drone images 25.09.2021 by IGME

The fissure eruption alternates between high explosive episodes and lesser ones.

Lapilli fell on Santa Cruz de La Palma, about 11 km from the volcano. Ashes and pyroclasts will continue to fall on the east of the island, depending on the direction of the winds. The firefighters of Gran Canaria, Lanzarote and Fuerteventura clean the ashes from the roofs of houses.

The Sentinel-5 P / Tropomi satellite detected a strong sulfur dioxide signal 14.4 km from the volcano on September 26, with 37.15 DU of SO2 at an altitude of about 2 km. The estimated mass is 57 , 3 ktons within 300 km.

La Palma - strong sulfur dioxide signal on 26.09.2021 at 14.4 km from the volcano, with 37.15 DU of SO2 at an altitude of about 2 km. - Image SEntinel-5P Tropomi / DLR / BIRA / ESA

La Palma - strong sulfur dioxide signal on 26.09.2021 at 14.4 km from the volcano, with 37.15 DU of SO2 at an altitude of about 2 km. - Image SEntinel-5P Tropomi / DLR / BIRA / ESA

La Palma - ash accumulation on the solar panels of IGNes monitoring stations, requiring constant maintenance - photo Itahiza 26.09.2021

La Palma - ash accumulation on the solar panels of IGNes monitoring stations, requiring constant maintenance - photo Itahiza 26.09.2021

The deformation recorded by the Canary Islands geodetic network over the past 24 hours shows a process of deflation, which would indicate a decrease in pressure in the Cumbre Vieja magmatic system.

A new seismic swarm, more to the south, indicates the intrusion of more magma under the island of La Palma, or in other words, more lava finding its way to the surface under the Cumbre Vieja volcano.

La Palma - new seismic swarm on 26.09.2021 - Doc. IGNes

La Palma - new seismic swarm on 26.09.2021 - Doc. IGNes

La Palma - Cumbre Vieja eruption - RSAM down at 09/27/2021 / 7:05 am - Doc. IGNes

La Palma - Cumbre Vieja eruption - RSAM down at 09/27/2021 / 7:05 am - Doc. IGNes

In particular, activity has fallen in recent hours in La Palma. Vigilance remains essential, as the situation can change rapidly.

The Canary Islands volcanic emergency plan ordered the containment on September 27 of four neighborhoods of the coast of La Palma in anticipation of the arrival of lava at sea in the coming hours.

 

Sources: IGNes, IGEM, InVolcan, INGV, RTVC, Tropomi

La Palma - the situation as at 27.09.2021 / 07:08 - Doc.Copernicus EMS

La Palma - the situation as at 27.09.2021 / 07:08 - Doc.Copernicus EMS

Last week, scientists from GNS conducted a gas emissions measurement flight at Whakaari / White Island, along with visual observations and temperature measurements from a helicopter.

Whakaari / White Island - the crater and its gas emissions - photo G. Novak / via G. Vitton

Whakaari / White Island - the crater and its gas emissions - photo G. Novak / via G. Vitton

Gas measurements showed sulfur dioxide (SO2) emissions increased to 680 tonnes per day from 450 tonnes per day in mid-August, a continuation of an upward trend in emission rates during the last few months.
Temperatures measured in the active ventilation zone rose from 650 ° C in July and August to a maximum of 189 ° C during last week's measurements.
Minor deposits from the intermittent ash emission described in previous bulletins were visible but were confined to the area near the active vents.

No ash emission occurred during observations made last week, however weak and intermittent ash emission is still possible.
Seismic activity remains similar to last week, with low levels of volcanic earthquakes and occasional low-frequency volcanic earthquakes.

Ground subsidence continues around the active vents, as measured by satellite remote sensing techniques, similar to the pattern in recent months.
The drop in temperatures around the ventilation zone is interpreted to reflect the infiltration of cooler soil and geothermal water into the active ventilation zone, caused by the decrease in gas pressure around the small volume of magma (rock molten) that we thought we had entered earlier in the year under the active vents.
However, the increased sulfur dioxide emissions may reflect a continued influx of magma deeper into the system, in an area unaffected by cooling groundwater.

The current level of activity corresponds to moderate to increased levels of restlessness. As such, the Volcanic Alert Level remains at 2 and the Aviation Color Code remains at yellow.

 

Source: GeoNet

Fagradalsfjall - the active site in a fumarole phase on 09/27/2021 / 07h48 - RUV webcam

Fagradalsfjall - the active site in a fumarole phase on 09/27/2021 / 07h48 - RUV webcam

In Fagradalsfjall, the volcano seems to remain in the fumarole phase, on hiatus for 9 days.

However, everything can change quickly ... only the volcano decides.

Fagradalsfjall - tremor at 27.09.2021 - Doc. Hraun.vedur.is

Fagradalsfjall - tremor at 27.09.2021 - Doc. Hraun.vedur.is

If the eruption continues, I think a Geldingadalir-sized lava lake will form ... It would then distribute the magma through pipes or lava conduits to active growing areas on the edges of the field. of lava. " says Þorvaldur Þórðarson, professor of volcanology at the University of Iceland, in a comment on mbls.

The Fagradalsfjall eruption is of the same type as previous eruptions on the Reykjanes Peninsula, which created shield volcanoes. Some of these eruptions lasted for years.

 

Sources: mbls, RUV, Hraun

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