Global Volcanism Network Bulletin v. 19, no. 6, June 1994
Kliuchevskoi (Kamchatka) Phreatic explosions; variable seismicity continues

Kamchatka Peninsula, Russia (56.06N, 160.64E)

Deep and shallow earthquakes, as well as volcanic tremor, continued to be recorded beneath the volcano in late May, June, and early July. In late May, between 13 and 44 events/day were recorded. The duration of volcanic tremor increased from 2.5 hours/day on 28 May to 21 hours on 30 May, but then decreased again to 2 hours on 31 May. During the first half of June, 5-20 weak, intermediate-depth earthquakes/day were detected; average duration of volcanic tremor increased from 16 to 24 hours/day during this period. This approximate level of activity continued through 25 June. In the last week of June, the number of weak intermediate-depth earthquakes increased to 18-46/day, but average tremor duration decreased to 0.3-1 hour/day. In early July, weak intermediate-depth earthquakes were recorded at a rate of 14-36/day; tremor was in the 14-24 hours/day range.

Weak fumarolic activity from the central crater was observed throughout June and early July. A steam plume on 10-11 June, possibly caused by a phreatic explosion, rose from the NW slope (2,500 m elevation) to about 4,500 m altitude. A phreatic explosion on 15 June from the NE slope produced a plume that rose 2-2.5 km.

Kliuchevskoi has erupted >80 times since 1697, including a large summit eruption in January 1990 (see Bulletin v. 15, no. 3). Several small ash emissions were reported in 1991-92 (see Bulletin v. 16, nos. 3, 4, and 6, and v. 17, nos. 1 and 5). The current activity began in mid-March 1993; gas-and-steam plumes (frequently with ash), tremor, and shallow earthquakes have persisted since then (see Bulletin v. 18, nos. 4-8 and 10-12, and v. 19, nos. 1, 3, and 4).