A NOAA/NESDIS scientist noted that a thermal anomaly at Sarychev Peak was identified in satellite images on 12 October. Robust thermal anomalies were identified on 14 October, and were accompanied by a plume of unknown composition. Thermal anomalies were also recorded by the MODVOLC and MIROVA thermal detection systems.

Geological Summary. Sarychev Peak, one of the most active volcanoes of the Kuril Islands, occupies the NW end of Matua Island in the central Kuriles. The andesitic central cone was constructed within a 3-3.5-km-wide caldera, whose rim is exposed only on the SW side. A dramatic 250-m-wide, very steep-walled crater with a jagged rim caps the volcano. The substantially higher SE rim forms the 1496 m high point of the island. Fresh-looking lava flows, prior to activity in 2009, had descended in all directions, often forming capes along the coast. Much of the lower-angle outer flanks of the volcano are overlain by pyroclastic-flow deposits. Eruptions have been recorded since the 1760s and include both quiet lava effusion and violent explosions. Large eruptions in 1946 and 2009 produced pyroclastic flows that reached the sea.

Sources: Michael J. Pavolonis (NOAA/NESDIS), via the Volcanic Clouds Listserv, Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts Team, MIROVA