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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
Whakaari / White island - sulfur fingers in a vent - photo 25.09.2019 via GNS

Whakaari / White island - sulfur fingers in a vent - photo 25.09.2019 via GNS

Whakaari / white island - field measurements on 25.09.2019 by GNS volcanologists

Whakaari / white island - field measurements on 25.09.2019 by GNS volcanologists

Over the last three weeks we have seen small mud and steam explosions in Whakaari / White Island, New Zealand, looking like geysers in the active ventilation zone.

These have reached a maximum height of about 10 meters. They pose no threat to visitors to the island and are not a sign of increasing volcanic activity. No changes in the parameters monitored outside the expected signals for minor volcanic disturbances, and the level of Whakaari / white island remains at level 1, with a color code aviation: green.

In the course of field measurements, volcanologists have discovered finger-like sulfur formations in the vapors emitted by a vent; they form when a stream of molten sulfur, at 115 ° C or more, cools and solidifies.

Sources: GeoNet / GNS

Karangetang - degassing of 2 summit craters on 26.09.2019 / 8:43 AM WITA - photo PVMBG

Karangetang - degassing of 2 summit craters on 26.09.2019 / 8:43 AM WITA - photo PVMBG

At Karangetang, on alert 3 / siaga, degassing is observed at a height of 300 meters above the summit, of white color and moderate intensity.
The lava flow of the main crater is observed at a distance of 1000-1500 meters in the western drainages.
Seismicity is characterized on September 25 by 146 earthquakes of eruption, 16 earthquakes of blast, 7 hybrid earthquakes, 3 distant tectonic earthquakes and the tremor of dominant amplitude to 2mm.

Source: PVMBG

Copahue, seen from Caviahue on 25.09.2019 - photo Valecaviahue / Twitter

Copahue, seen from Caviahue on 25.09.2019 - photo Valecaviahue / Twitter

In Copahue, since mid-September, LP earthquakes of low energy, in relation with a superficial volcanic activity in the crater, are observed.

This activity is manifested by a continuous degassing, more intensely observed according to the atmospheric conditions, and sometimes charged with ashes, which darken the snow-covered slopes.

 

Sources: Sernageomin & Valecaviahue / Twitter

Mayotte - ongoing seismic-volcanic crisis - image archives Mayotte Newspaper / Mayobs Campaign2

Mayotte - ongoing seismic-volcanic crisis - image archives Mayotte Newspaper / Mayobs Campaign2

The prefecture of Mayotte has issued a warning and safety instructions in case of marine submersion during high tides (with waves around 4 meters) that should impact the island from 28 September to 2 October.
These tides, usual at this time of the year, are worrying because of the subsidence of the island from 9 to 15 cm. following the ongoing seismo-volcanic activity; homes near the coast, roads and part of the runways of the airport may be submerged.


The French authorities have set up a magneto-telluric measurements campaign on Mayotte in order to better understand groundwater fluctuations.

Sources: Prefecture of Mayotte and REVOSIMA

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