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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 : #Actualités volcaniques

In Vanuatu, on Ambae, a brief eruptive episode marked, this 4th of January, the cone of Lake Voui, where a new crater would have opened in the lava field at the foot of the cone (radar images Sentinel 1 / via Culture volcano) -

A new phase of activity is observed on the webcam on January 27 around 11 pm, as well as a thermal anomaly.

The Vanuatu Geohazard Observatory reports a change of style of activity characterized by audible explosions in the vicinity and vapor plumes, containing little ashes. Nighttime glow is observed ... an activity of the type found at Yasur on the island of Tanna.

At the same time, he recalls that the forbidden zone of 2km radius around the vent remains in force due to projectiles and possible gas emission.
 

Ambae - Thermal Anomalies of January 2018 - Doc. Mirova Modis

Ambae - Thermal Anomalies of January 2018 - Doc. Mirova Modis

On Vanua Lava, alert level 1 since May 27, 2016, recent observations indicate signs of instability; it is recommended not to approach the volcano and the Sufur river, areas where volcanic gases are likely to be emitted.

The Suretamatai Volcano forms the largest part of Vanua Lava Island, one of the largest of Vanuatu's Banks Islands. The young lavas of Suretamatai (921 m high, also known as Soritimeat) cover a number of small, aged stratovolcans that form the island. Unlike other large volcanoes in Vanuatu, the predominantly basaltic to andesitic Suretamatai does not contain a young top in a caldera. A chain of small stratovolcanoes, oriented along a NNE-SSW line, gives the low inclination volcano an irregular profile. The youngest cone, near the northern end of the range, is the largest and contains a lake of varying depth in its crater 900 m wide, at the top, with 100 m depth. Historical activity, beginning during the 19th century, was limited to moderate explosive eruptions.

Sources: Vanuatu Geohazards Observatory, Watchers, Mirova & Culture Volcano.

partial view of Vanua Lava taken from the ISS - the active volcano Suretamatai is located under the clouds at the top of the image - NASA Space Shuttle image ISS006-E-40035, 2003

partial view of Vanua Lava taken from the ISS - the active volcano Suretamatai is located under the clouds at the top of the image - NASA Space Shuttle image ISS006-E-40035, 2003

In Kusatsu-Shirane, after the eruption of 23 January, the alert is maintained at level 3 by the JMA, accompanied by a prohibited area of ​​2 km radius around the Kagamiike.

Numerous volcanic earthquakes have been recorded since, including two on January 28 at around 3 pm, and four episodes of tremor on January 24, and two on January 25.

Source: Japan Times

Kusatsu - one of the craters spotted by the satellite 26 - photo Kyodo / Japan times

Kusatsu - one of the craters spotted by the satellite 26 - photo Kyodo / Japan times

After the observation of volcanic tremor on January 28 at 19h and January 30 before 01h, then between 5:18 and 5:49 UTC, in connection with the movement of fluids, and a small inflation, the JMA raised the alert of Zaozan, on the main island of Honshu, to 2 / do not approach the crater on January 30 at 14:38 JST.

Volcanic gas discharges are observed at the Umanose caldera.

The authorities have warned the nearby ski resort to remain alert, especially after the appearance of a controversy reproaching them a late warning to Kusatsu.

Zaosan forms the central group of a stratovolcano complex; it is surmounted by several lava domes and the Goshikidake tuff cone, which contains the Okama crater, active and filled with a strongly acid colored lake. Its historical eruptions date back to the 8th century; the last date of May 18, 1940.

Sources: NHK & Global Volcanism Program / Zaozan

The Okama crater of Zaozan - Kyodo photo

The Okama crater of Zaozan - Kyodo photo

In the Mayon, two collapses caused pyroclastic flows on January 30: the first at 11:51, in the Miisi drainage, was accompanied by a cloud of ash rising to 1,250 meters drifting southwest; two other flows followed in the Basud darinages and lasted until 12:09, with a cloud of ash drifting to the southwest.

Whitish to light gray plumes were then continuously emitted; Sporadic ash emissions began at 17:11, followed by a slow lava effusion and continued in the evening and early morning, feeding the lava flows in the Miisi and Bonga drainages.

Lava fountains, intermittent and of short duration, were observed during the night.

Mayon - pyroclastic flow of 30.01.2018 and ash cloud - photo Phivolcs

Mayon - pyroclastic flow of 30.01.2018 and ash cloud - photo Phivolcs

The change in behavior with previous eruptions, with plumes clearer and lower, is reported by the observatory of Mayon and justified an investigative flight.

Sources: Phivolcs & Rappler

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