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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
 Shishaldin - image Sentinel-2 Copernicus of 24.10.2019 - via Antonio Vecoli / Twitter

Shishaldin - image Sentinel-2 Copernicus of 24.10.2019 - via Antonio Vecoli / Twitter

Delayed following the eruption of La Fournaise ...

 

The Shishaldin, in the Aleutian volcanic arc, in eruption since July 23, 2019, is in Watch alert level, with an orange aviation code.

Satellite data from October 23 show that the lava now fills the summit crater and begins to sink on the edge of the north crater at two locations.

On October 24th, a 200 m (600 ft) long lava flow melted the snow and produced a large 2.9 km (1.8 mile) lahar which spreads on the north flank, reaching about 1230 m. m (~ 4000 ft) altitude.

A small lava flow produced a lahar about 1 km long on the northeast flank.

Spatters of low intensity explosive activity also accumulate around the crater rim and melt the snow. This activity coincided with very high surface temperatures, high seismicity and infrasound detections. There has been no evidence of significant volcanic plumes containing ashes during the past day in murky satellite images and web cameras.

Shishaldin is monitored by local seismic and infrasound sensors, satellite data, a web camera, a range geodetic network, and remote infrasound and lightning networks.

 

Source: AVO

Shishaldin - Thermal anomalies on 25.10.2019 / 08h50 - Doc. Mirova
Shishaldin - Thermal anomalies on 25.10.2019 / 08h50 - Doc. Mirova

Shishaldin - Thermal anomalies on 25.10.2019 / 08h50 - Doc. Mirova

 Shishaldin - 21.10.2019 / 12:09 AKDT - AVO webcam

 Shishaldin - 21.10.2019 / 12:09 AKDT - AVO webcam

Eruption of Piton de la Fournaise October 25, 2019 Reunion Island by Ilotdrones in night flight

The eruptive activity that began on October 25, 2019 at Piton de la Fournaise at 2:40 pm local time continues.

The front of the lava flow was at 17:00 on October 26 about 250m from the national road 2.

The front of the flow has increased by about 150m in 9h. The progression of the flows is now on average slopes of 19% (against 16% this morning).
The slow progression of the casting front of these last hours is explained by the decrease of surface flows and by the slopes which are lower than those traversed by the lava during the day of 25/10/2019.

On the morning of October 27, the activity is generally at half-mast: a single fountain of lava animates the eruptive cone; a third casting, which had rounded Piton Tremblet on Saturday afternoon, stopped; and the casting near the RN2 has frozen and no longer glows.

The thermal anomalies recorded by Mirova follow the activity.

Piton de La Fournaise - the eruptive cone and lava flows on 26.10.2019 - photo OVPF

Piton de La Fournaise - the eruptive cone and lava flows on 26.10.2019 - photo OVPF

Piton de La Fournaise - lava flow 26.10.2019 - OVPF photo

Piton de La Fournaise - lava flow 26.10.2019 - OVPF photo

Piton de La Fournaise - thelava flow front at 250 meters from the RN2 26.10.2019 at 17h loc OVPF

Piton de La Fournaise - thelava flow front at 250 meters from the RN2 26.10.2019 at 17h loc OVPF

Piton de La Fournaise - thermal anomalies at 27.10.2019 / 6h00 - Doc.Mirova

Piton de La Fournaise - thermal anomalies at 27.10.2019 / 6h00 - Doc.Mirova

Update 12h local time : the intensity of the tremor (indicator of the intensity of the eruption) shows signs of fluctuation since 02h45 local time (22h45 UTC) that day. The phases of increase and decrease are to be related to the construction / dismantling of the volcanic cone that has formed, by accumulation of lava fountain products, at the level of the eruptive vent and which increases / decreases the pressure at the exit point of the lava and thus affect the intensity of the seismic noise.

Piton de La Fournaise - Evolution of the RSAM (indicator of the volcanic tremor and the intensity of the eruption) between 04:00 (00:00 UTC) on October 25 and October 27 at 11:45 (07:15 UTC) on the GPS seismic station, the Closer to the eruptive site (© OVPF / IPGP).

Piton de La Fournaise - Evolution of the RSAM (indicator of the volcanic tremor and the intensity of the eruption) between 04:00 (00:00 UTC) on October 25 and October 27 at 11:45 (07:15 UTC) on the GPS seismic station, the Closer to the eruptive site (© OVPF / IPGP).

The observations made on site this morning by a team from the observatory show that:

the eruptive activity at the level of the eruptive site, located at 1050 m of altitude, is weak. The height of the lava projections is less than 20 m, and the cone that has been built is about ten meters high. This morning at 8am (local time), only one active flow was present and was discharging over a distance of less than 200m from the eruptive cone.

The lava flow front closest to the RN2 was frozen and was no longer progressing. It was this morning at 8am (local time) still about 250m from the RN2 (Figures 4 and 5).

The lava arm around the Piton Tremblet by the south at the end of yesterday was also frozen

On the day of October 26, 29 superficial volcanic-tectonic earthquakes were recorded.

 

After the strong deformations related to the magma transfer to the surface that occurred on October 25, 2019, no particular deformation signal is recorded.

The surface flows estimated from the satellite data, via the HOTVOLC platform (OPGC - University Clermont Auvergne) were included in the last 24h between <1 and 10 m3 / s (these measures can be largely affected / reduced by the cloud cover) with a downward trend over the last 24 hours.

SMOG is visble over the island. 

 

Sources: OVPF & local media and observers

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

Piton de La Fournaise - 27.10.2019 the eruptive cone - photo OVPF

Piton de La Fournaise - 27.10.2019 the eruptive cone - photo OVPF

According to Magma Indonesia, several eruptive episodes marked Anak Krakatau on October 26 and 27, 2019.

Two orange Vona were issued on 26.10, the first at 08:02 local, with visual observation of ashes emitted 200 meters high to the north; the imprint on the seismogram is of a max. 40 mm and a duration of 738 seconds.

The second episode is observed, similar to the previous one at 16:09 local, with a seismographic fingerprint of max amplitude. of 50 mm, and a duration of 687 sec.

Anak Krakatau - eruptive episodes of 26.10.2019, respectively at 8:05 and 16:12 - webcam PVMBG
Anak Krakatau - eruptive episodes of 26.10.2019, respectively at 8:05 and 16:12 - webcam PVMBG

Anak Krakatau - eruptive episodes of 26.10.2019, respectively at 8:05 and 16:12 - webcam PVMBG

Anak Krakatau - seismograms of 26 and 27.10.2019 - Doc. Magma Indonesia - one click to enlargeAnak Krakatau - seismograms of 26 and 27.10.2019 - Doc. Magma Indonesia - one click to enlarge

Anak Krakatau - seismograms of 26 and 27.10.2019 - Doc. Magma Indonesia - one click to enlarge

Two orange Vona on October 27: the first episode at 01:02 local, recorded on the seismogram with a max amplitude. 47 mm, for 120 sec. ; the second, at 5:43 am local, with max. 45 mm for 69 sec., Accompanied by ash 150 meters high to the north.

 

Sources: Magma Indonesia and PVMBG

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