KVERT reported that on 15 July moderate gas-and-steam activity was observed at Zhupanovsky. On 16-17 July satellite data showed ash plumes that rose to 6-6.5 km (19,700-21,300 ft) a.s.l. and extended about 370 km N. A thermal anomaly was observed over the volcano on 16 July. The Tokyo VAAC reported ash plumes during 16-18 and 21 July drifting N and NE. Plume altitudes were in the range of 3.3-8.5 km (11,000-28,000 ft) a.s.l.

Geological Summary. The Zhupanovsky volcanic massif consists of four overlapping stratovolcanoes along a WNW-trending ridge. The elongated complex was constructed within a Pliocene-early Pleistocene caldera whose rim is exposed only on the eastern side. Three of the stratovolcanoes were built during the Pleistocene. An early Holocene stage of frequent moderate and weak eruptions from 7,000 to 5,000 years before present (BP) was followed by a period of infrequent larger eruptions that produced pyroclastic flows. The last major eruption took place about 800-900 BP. Recorded eruptions have consisted of relatively minor explosions from Priemysh, the third cone from the E about 2.5 km from the summit peak.

Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Tokyo Volcanic Ash Advisory Center (VAAC)