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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
 Anak Krakatau - image Planet Labs via Samir Madani Twitter 30.12.2018

Anak Krakatau - image Planet Labs via Samir Madani Twitter 30.12.2018

The latest photos of Anak Krakatau (which may be renamed the "second child") provided by Planet Labs show that almost the entire island, with the exception of a northwestern part, is covered with tephra recent; a crescent of tufa is occupied to build up at the edge of the bay dug by the eruption of December 22, 2018 and a large fringe of sea water is discolored under the effect of the submarine degassing.

Evolution of Anak Krakatau on 28.12.2018 - Doc. GFZ Postdam via Daryono BMKG

Evolution of Anak Krakatau on 28.12.2018 - Doc. GFZ Postdam via Daryono BMKG

A Sentinel 2 image reveals various hot spots around the newly formed bay.

Surtseyen-type activity continued, and an orange VONA was issued on the morning of January 2, following an eruption accompanied by an ash plume rising to 1,610 meters at 2:38 UTC / 9:38 local, which lasted 71 sec. Dissipation occurred to the northeast.

Anak Krakatau - image Sentinel-2 image bands 12,11,4 / 29.12.2018, maximized to reveal the hot pixels at the eruptive vent and the SSW

Anak Krakatau - image Sentinel-2 image bands 12,11,4 / 29.12.2018, maximized to reveal the hot pixels at the eruptive vent and the SSW

A synoptic table of volcanic activity in Indonesia and their current level has been provided by the PVMBG: of the 127 existing volcanoes, 69 are monitored 24 hours a day; Sinabung is at maximum activity level 4 / Awas; four volcanoes, Agung, Soputa, Karangetang and Anak Krakatau are in level 3 / Siaga; fifteen volcanoes remain in level 2 / waspada and 48 in level 1 / normal.

Sources: PVMBG, Planet Labs and Sentinel 2

Indonesia - status of 69 volcanoes under continuous surveillance - Doc PVMBG 02.01.2019

Indonesia - status of 69 volcanoes under continuous surveillance - Doc PVMBG 02.01.2019

In Kamchatka, the eruption in progress at Sheveluch continues with this January 2 a plume of gas and steam, containing small amounts of ash, and reaching 4,500 meters asl. before drifting southeast 85 km.

According to Volkstat, the ashes of previous days have covered a vast territory. The whole Klyuchevskaya group, the village of Klyuchi and even the village of Kozyrevsk are covered with ashes. The maximum amount was observed 35 km from Klyuchi in a northwesterly direction on the road to the Kura test site.

The photos show a night glow due to falling rocks.

Sources: KVERT & Volkstat

Sheveluch - 31.12.2018 -12h23 - photo Volkstat.ru

Sheveluch - 31.12.2018 -12h23 - photo Volkstat.ru

Sheveluch - night glow on 31.12.2018 / 08h15 and ash sample collection - photos Volkstat.ru  - one click to enlarge
Sheveluch - night glow on 31.12.2018 / 08h15 and ash sample collection - photos Volkstat.ru  - one click to enlarge

Sheveluch - night glow on 31.12.2018 / 08h15 and ash sample collection - photos Volkstat.ru - one click to enlarge

In Pacaya / Guatemala, strombolian eruption continues in Mackenney crater, with small explosions at 30 m. high, and a lava flow 200 meters long on the west flank.

The seismicity is marked by an internal tremor, generated by the degassing, the rise of the magma and the explosions.

Sources: Insivumeh, Mirova, and Rüdiger Escobar Wolf / MTU

Pacaya - Sentinel image 2 bands 12,11,5, SWIR-Visible by R.E.Wolf MTU / 31.12.2018

Pacaya - Sentinel image 2 bands 12,11,5, SWIR-Visible by R.E.Wolf MTU / 31.12.2018

The month of December 2018 was marked in the Piton de la Fournaise by a low seismicity under the summit craters, a lack of significant deformation, and CO2 fluxes in the ground in far field relatively constant on low values. This testifies to the absence of magmatic transfers (or at least their slowdown) from the deep zones to the more superficial zones. 

Piton de la Fournaise - location and depth of major earthquakes of December 2018 - Doc OVPF / Twitter

Piton de la Fournaise - location and depth of major earthquakes of December 2018 - Doc OVPF / Twitter

In Mayotte, in December, the month was particularly active with several earthquakes of Magnitude> 4 felt.

In parallel, data from the Teria network's GPS stations installed on the island of Mayotte, which are distributed by the RGP of the Institut Géographique National (IGN), have always indicated since July an overall shift towards the is (about 11 cm since July) and subsidence (subsidence) (about 8 cm since July). Automatic and daily calculations have been set up at the OVPF (via the Gipsy software) in order to follow these deformations, as well as the source at their origin.

Thus for the last 3 months, the source of "depressurization" at the origin of these movements could be located about thirty km east of Mayotte and about 39 km deep. This suggests that fluid transfers in the crust are still continuing.

Source: OVPF

Mayotte - earthquake swarm, displacements InSAR - Doc. Matarikipax Twitter

Mayotte - earthquake swarm, displacements InSAR - Doc. Matarikipax Twitter

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