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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

The eruption that began at Piton de La Fournaise on 12/22/2021 at around 3:30 a.m. local time continues.

Following the decrease of the first lava fountains, the amplitude of the eruptive tremor (indicator of a lava emission on the surface) stabilized during the day of December 23, at about 30% of its initial amplitude. The amplitude of the tremor is on the morning of December 25 at about 20% of its initial amplitude.

Piton de La Fournaise - overview of the eruptive site on 12/24/2021 - OVPF photo - - one click to enlarge

Piton de La Fournaise - overview of the eruptive site on 12/24/2021 - OVPF photo - - one click to enlarge

At around 9:00 a.m. local time on December 23, the lava flow had traveled 2.4 km from its point of emission (and was at an altitude of around 2,000 m). The flow front was 540 m from the southern rampart, about 2 km from the top of the major slopes, about 8 km from the road, and about 9 km from the ocean.

Since 12.23.2021 evening, thanks to the closure of the eruptive cone, activity in lava tunnels has taken place at the foot of the cone. These tunnels extend a length of a hundred meters before the flow emerges in a single channel further downstream. Observations on site show that the regime of lava fountains within the cone, although still active, is low and the lava fountains exceed the height of the cone (<15 m) only intermittently.

Piton de La Fournaise - location of the flow as at 24.12.2021 - Doc. OVPF

Piton de La Fournaise - location of the flow as at 24.12.2021 - Doc. OVPF

Over the last 24 hours:

- A single superficial earthquake, of low magnitude (<0.5), was recorded directly above the summit.

- The surface deformations show a slight deflation at the level of the summit zone, linked to the emptying of the magma reservoir located under the summit (at about 2-2.5 km deep) feeding the eruptive site.

- The lava flow estimates, established by satellite method with the HOTVOLC platform (OPGC - Clermont Auvergne University), are between 2 and 12 m3 / sec, with an average of 5 m3 / sec.

- The front of the flow, in gratons, currently on a relatively flat area, moves only very slowly, between December 23 and 24 the front had progressed by less than 100 m and was located around 7.6 km from the national road 2.

 

Source: OVPF

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

the website: ipgp.fr/fr/ovpf/actualites-ovpf

- the Twitter account: twitter.com/obsfournaise

- the Facebook account: facebook.com/ObsVolcanoPitonFournaise.

La Palma - Cumbre Vieja - overview of the eruptive fissure and craters - InVolcan photo - one click to enlarge

La Palma - Cumbre Vieja - overview of the eruptive fissure and craters - InVolcan photo - one click to enlarge

The eruption of Cumbre Vieja is officially over, Julio Pérez, director of the Canary Islands Volcanic Emergency Plan (Pevolca), told a press conference on Saturday.

"There is no lava, no significant gas emission, no significant earthquakes," said the official, recalling that this eruption lasted 85 days and 8 hours, from September 19 at 3.10 p.m. until December 13 at 10 p.m.

The volcano La Palma has a volcanic edifice approximately 200 m high above its base, with a total altitude of approximately 1,100 meters above sea level, around an eruptive fissure visible from the sky with at least 6 craters.

The emergency is not yet over and PEVOLCA remains on red alert, because the end of the eruption does not necessarily imply the cessation of the dangers linked to the volcanic phenomenon or to the magmatic reactivation at Cumbre Vieja. Surveillance work is continuing and relocation plans will be studied so that they can begin during the first half of January. During the eruptive process, 7,000 people were evacuated. According to the land registry, 1,676 houses and buildings were affected. There are 370 damaged cultivated hectares, most of which are bananas. As for the operation of La Palma airport, during this episode it was closed for a total of nine and a half days and more than 500 operations were canceled.

 

Sources: InVolcan, IGN, IGME, DSN, Copernicus

La Palma / Cumbre Vieja - gas sampling in one of the craters, and sulfur deposits - InVolcan photos 23.12.2021 - one click to enlargeLa Palma / Cumbre Vieja - gas sampling in one of the craters, and sulfur deposits - InVolcan photos 23.12.2021 - one click to enlarge

La Palma / Cumbre Vieja - gas sampling in one of the craters, and sulfur deposits - InVolcan photos 23.12.2021 - one click to enlarge

In the Reykjanes Peninsula, no truce for Christmas :

The latest InSAR also suggests a dike intrusion at the same location as this spring (Feb 24-Mar 19). Seismicity is still high and today an M4.7 at 3:03 pm occurred east of the crater (Stóri Hrútur). A new eruption has not yet started ...

The map below shows the spring swarm (M3-M5.7) in blue and the Christmas swarm (started 12/21) (M3-M4.9) in red. The morning earthquakes were felt in Reykjavík!

(Kristín Jónsdóttir - IMO)

Reykjanes Peninsula - 12.25.2021 - no visible traces of eruption - mbls webcam

Reykjanes Peninsula - 12.25.2021 - no visible traces of eruption - mbls webcam

Reykjanes Peninsula -spring swarm (M3-M5.7) in blue and Christmas swarm in red (started 12/21) (M3-M4.9). -  Document 25.12.2021 K. Jonsdottir

Reykjanes Peninsula -spring swarm (M3-M5.7) in blue and Christmas swarm in red (started 12/21) (M3-M4.9). - Document 25.12.2021 K. Jonsdottir

Reykjanes Peninsula - seismic parameters as of 23.12.2021 - Doc. Vedur

Reykjanes Peninsula - seismic parameters as of 23.12.2021 - Doc. Vedur

Yesterday, Christmas Day, more than 3,000 earthquakes were measured at Fagradalsfjall, the largest magnitude 4.2 at 7:26 a.m. Since the start of the eruption, approximately 15,000 earthquakes have been detected, of which fourteen have a magnitude of 4.0 or greater.

 

Sources: IMO, mbls

Reykjanes Peninsula - location and magnitude of the earthquakes of the current swarm, as of 12/26/2021 / 7:30 a.m. - IMO Doc
Reykjanes Peninsula - location and magnitude of the earthquakes of the current swarm, as of 12/26/2021 / 7:30 a.m. - IMO Doc
Reykjanes Peninsula - location and magnitude of the earthquakes of the current swarm, as of 12/26/2021 / 7:30 a.m. - IMO Doc

Reykjanes Peninsula - location and magnitude of the earthquakes of the current swarm, as of 12/26/2021 / 7:30 a.m. - IMO Doc

Reykjanes peninsula - trémor at Fagradalsfjall & Grindavik , on 26.12.2021 - Doc. Hraun.vedur.is - one click to enlargeReykjanes peninsula - trémor at Fagradalsfjall & Grindavik , on 26.12.2021 - Doc. Hraun.vedur.is - one click to enlarge

Reykjanes peninsula - trémor at Fagradalsfjall & Grindavik , on 26.12.2021 - Doc. Hraun.vedur.is - one click to enlarge

In a news report, Tonga's chief geologist reported that the eruption at Hunga Tonga-Hunga Ha'apai, which began at 9:35 a.m. on December 20, is continuing.

The eruption produced a vapor-rich gas and ash plume that initially reached 6 km above sea level. at 9:40 a.m., then continued to climb to an altitude of 16 km. and drift north. Lightning was present in the plume and about 9 kilotons of sulfur dioxide were detected in satellite data. Residents of Vava'u, 270 km northeast, heard a series of explosions at a rate of several times per minute for the first 1 to 2 hours, after which they became sporadic. Explosions were heard overnight in the first 12 hours of the eruption.

Ash emissions ceased around 2:00 a.m. on December 21, although intermittent gas plumes with lightning continued at least throughout that day. Based on the pilots' observations, the Wellington VAAC noted that the plumes were 6.1 to 12.2 km above sea level. and drifted N and NE on December 21.

An image from the Sentinel-2 satellite, taken on December 23 at 10 p.m. UTC, reveals a plume of gas and water vapor that completely eclipses the island. An area of ​​water discoloration attests to the presence of dissolved and / or suspended substances emitted by the eruption.

Large rafts of pumice float away adrift in a northwesterly direction.

 

Sources: Chief Geologist of Tonga, and Sentinel-2 Copernicus

Hunga Tonga-Hunga Ha'apai - 12/23/2021 / 10 p.m. - gas and water vapor obscure the island; pumice rafts are visible far from the island (bottom left corner of the image) - image Sentinel-2 Copernicus - one click to enlarge

Hunga Tonga-Hunga Ha'apai - 12/23/2021 / 10 p.m. - gas and water vapor obscure the island; pumice rafts are visible far from the island (bottom left corner of the image) - image Sentinel-2 Copernicus - one click to enlarge

Hunga Tonga-Hunga Ha'apai - 12.23.2021 - gas and water vapor obscures the island, and areas of discolored water surround it - image Sentinel-2 Copernicus - one click to enlarge

Hunga Tonga-Hunga Ha'apai - 12.23.2021 - gas and water vapor obscures the island, and areas of discolored water surround it - image Sentinel-2 Copernicus - one click to enlarge

Hunga Tonga-Hunga Ha'apai - 23.12.2021- pumice rafts drift southwest of the eruptive site - image Sentinel-2 Copernicus - one click to enlarge

Hunga Tonga-Hunga Ha'apai - 23.12.2021- pumice rafts drift southwest of the eruptive site - image Sentinel-2 Copernicus - one click to enlarge

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