A bit of instability characterizes the Great Sitkin in the Aleutian arc: an increase in seismicity in recent months and recent observation of a vigorous plume of steam motivated the AVO to increase the level of alert to Advisory and aviation code in Yellow.
On November 19, the slightly colored vapor plume rose 300 meters above the vent zone and extended 15-20 km to the south.
Its last activity dates back to 1974, characterized by a plume that reached 7,600 meters asl. and a lava flow that covered 600,000m² of the summit crater floor.
At Agung, the seismicity remains low and a plume of white vapor rises 100-400 meters above the crater. The alert level remains at III.
Sources: PVMBG & Magma Indonesia
Agung 23.11.2017 / 11:56 WITA - the white vapor plume merges with the clouds - photo Magma Indonesia
The GVP reports, via SVERT, low steam and gas emissions at Sarychev peak / Kuriles archipelago on 13 November. The volcano was not observable between 14 and 20 November, under the clouds.
The aviation code remains green.
To note: a thermal anomaly was spotted by Mirova Modis on November 7 and 8, 2017, confirmed by the images of the satellite Sentinel2, which show a gas plume and traces of a lava flow from the top of the volcano on the flank NSN.
Sources: Sakhalin Volcanic Response Team Eruption (SVERT) & Mirova