SVERT reported that a thermal anomaly was detected over Snow, a volcano of Chirpoi, during 17, 19, and 21-22 December. A steam-and-gas plume was observed on 19 December. Cloud cover prevented observations of the volcano on the other days during 10-17 December.

Geological Summary. Chirpoi, a small island lying between the larger islands of Simushir and Urup, contains a half dozen volcanic edifices constructed within an 8-9 km wide, partially submerged caldera. The southern rim of the caldera is exposed on nearby Brat Chirpoev Island. The symmetrical Cherny volcano, which forms the central cone of the island, erupted twice during the 18th and 19th centuries. The youngest volcano, Snow, originated between 1770 and 1810. It is composed almost entirely of lava flows, many of which have reached the sea on the southern coast. No recorded eruptions are known from Brat Chirpoev, but its youthful morphology suggests recent Strombolian activity.

Source: Sakhalin Volcanic Eruption Response Team (SVERT)