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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

A sharp fall in the intensity of the tremor was observed on April 6, around 1:30 p.m. local time (9:30 a.m. UT), announcing the end of the eruption on the surface at Piton de La Fournaise.

No hypothesis is ruled out as for the evolution of the situation to come (final stop, resumption of the activity on the same site, resumption of the activity on another site), taking into account the strong seismicity recorded since the day of 5/4/2020 00h (UT time) and until 09h (UT time; 13h local time) this day: with 243 superficial volcano-tectonic earthquakes (<2km deep) recorded under the summit craters. Even if since the end of the eruption the seismic activity has considerably decreased.

Piton de La Fournaise - Evolution of the RSAM (indicator of the volcanic tremor and the intensity of the eruption) since 02/04/2020 00h UT time (04h local time) on the seismological station DSO located at the top of the volcano, at 06.04.2020 (© OVPF / IPGP).

Piton de La Fournaise - Evolution of the RSAM (indicator of the volcanic tremor and the intensity of the eruption) since 02/04/2020 00h UT time (04h local time) on the seismological station DSO located at the top of the volcano, at 06.04.2020 (© OVPF / IPGP).

Piton de La Fournaise - 06.04.2020 - Spectrogram of the GPN seismological station, located in the Great Slopes (© OVPF / IPGP).

Piton de La Fournaise - 06.04.2020 - Spectrogram of the GPN seismological station, located in the Great Slopes (© OVPF / IPGP).

Following a reconnaissance flight by the SAG and the PGHM carried out this morning at around 10 am local time, the lava flow front could be located with precision (white star on the map). The active front (south casting arm) was located at 360 m altitude, about 2 km from national road 2 (against 550 m altitude and 2.7 km from the road yesterday at 10:30 am for the casting arm North).

The thermal images acquired last night by a team from the OVPF / IPGP made it possible to estimate a forward speed of the casting front of 40-60 m / h during the evening of 05.04.2020.

In an interview with Info.re, Aline Peltier, director of the Observatory, summarizes what must be remembered from the eruption from 2 to 6 April 2020 : few warning signs (both in terms of seismicity and deformation), a impressive flow and fountains (with production of many Pele hair) and seismicity under the summit which raised fears of a crater collapse.

Piton de La Fournaise - Mapping of the lava flow dated 4/4/2020 (orange) and 5/4/2020 (red) deduced from satellite images. The white stars represent the position of the casting front on 5/4/2020 at 10:30 a.m. local time (6:30 a.m. UT) and 6/4/2020 at 10 a.m. local time (6 a.m. UT). The dotted line represents the line of greatest slope (© OVPF / IPGP / LMV / OPGC).

Piton de La Fournaise - Mapping of the lava flow dated 4/4/2020 (orange) and 5/4/2020 (red) deduced from satellite images. The white stars represent the position of the casting front on 5/4/2020 at 10:30 a.m. local time (6:30 a.m. UT) and 6/4/2020 at 10 a.m. local time (6 a.m. UT). The dotted line represents the line of greatest slope (© OVPF / IPGP / LMV / OPGC).

Despite the end of the eruption at Piton de La Fournaise on 06.04.2020 around 1:30 p.m., glowing is still visible. These are linked to the lava flows being cooled and to the lava tunnels which drain. - Cascades / OVPF webcam

Despite the end of the eruption at Piton de La Fournaise on 06.04.2020 around 1:30 p.m., glowing is still visible. These are linked to the lava flows being cooled and to the lava tunnels which drain. - Cascades / OVPF webcam

Piton de La Fournaise - thermal anomalies on 06.04.2020 / 21h05, downing with the eruption stop - Doc. Mirova Modis

Piton de La Fournaise - thermal anomalies on 06.04.2020 / 21h05, downing with the eruption stop - Doc. Mirova Modis

Piton de La Fournaise - 06.04.2020- SO2 emissions spotted by the Sentinel-5 P Tropomi -Doc satellite. DLR / BIRA / ESA

Piton de La Fournaise - 06.04.2020- SO2 emissions spotted by the Sentinel-5 P Tropomi -Doc satellite. DLR / BIRA / ESA

Large quantities of Pelé hair were again reported this April 6 in the areas located north of the volcano, especially in the La Plaine des Cafres sector where their dispersion was the highest. This Pelé hair is formed under the action of the wind, when the lava ejecta from the fountains at the eruptive site are stretched and transported by the wind.


In the Plaine de Cafres, this hair, gathered under the action of the wind, formed tufts of several tens of cm in length (hair mattress). There are also reports of hair fallout from Pelé from the Ravine des Cabris (Saint Pierre) to Sainte Marie, via Le Tampon, and the Plains region.

Piton de La Fournaise - tuft of pele hair - photo Reunion Prefecture

Piton de La Fournaise - tuft of pele hair - photo Reunion Prefecture

Piton de La Fournaise - Pelé's hair carpet in the Plaine des Sables under the action of the volcano, wind and terrain - photo Entreprise Adevo Elevage du Volcan 05.04.2020 / via OVPF

Piton de La Fournaise - Pelé's hair carpet in the Plaine des Sables under the action of the volcano, wind and terrain - photo Entreprise Adevo Elevage du Volcan 05.04.2020 / via OVPF

With the cessation of the eruption at Piton de La Fournaise, the Prefecture decrees the transition to the "backup phase" of the specific ORSEC device of the Piton de la Fournaise Volcano on Monday, April 6, 2020 at 4 p.m.

It further recommends:
- to the inhabitants of La Plaine des Cafres, and by extension, the inhabitants of the municipalities of Saint-Joseph, Saint-Philippe, Sainte-Rose and Le Tampon, to be in alert to the fallout of Pélé's hair; to clean the surfaces so that they get rid of Pélé's hair, which would have accumulated there; wash vegetables and fruit from gardens thoroughly; avoid handling Pelé's hair with bare hands; and if it comes into contact with Pélé's hair, wash it thoroughly with water.

Avoid frequentation by children of outdoor spaces where the presence of Pélé hair is noted.

- to the people, who are likely to go to the site of the eruption for professional reasons, to avoid contact between food and the surfaces on which Pélé's hair has accumulated; especially during picnics; and avoid handling Pelé's hair with bare hands; in case of contact, wash thoroughly with water.

 

Source: OVPF, Reunion Prefecture & Adevo élevage du volcan

Find all the information relating to the activity of Piton de la Fournaise on the various media of the OVPF-IPGP:
- the website (http://www.ipgp.fr/fr/ovpf/actualites-ovpf),
- the Twitter account (https://twitter.com/obsfournaise?lang=fr),
- and the facebook account (https://www.facebook.com/ObsVolcanoPitonFournaise/)

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