Report on Gorely (Russia) — 23 October-29 October 2002
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 23 October-29 October 2002
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2002. Report on Gorely (Russia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 23 October-29 October 2002. Smithsonian Institution and US Geological Survey.
52.559°N, 158.03°E; summit elev. 1799 m
All times are local (unless otherwise noted)
According to a Pravda news article, the Laboratory of Active Volcanism at the Institute of Volcanology reported that a seismic station located atop Gorely registered continuous tremor that was four times stronger than background tremor. In addition, "smoke" and steam rose 300 m above the volcano. Another report from the Kamchatkan Experimental-Methodical Seismological Department, which operates the seismic station, stated that the station is in the vicinity of both Gorely and Mutnovsky, therefore it is difficult to attribute the tremor to a specific volcano. They found that during 2-3 October a swarm of about 30 M 1.2-1.7 earthquakes was recorded, and on 26 October there were two M 1.7 earthquakes.
Geologic Background. Gorely volcano consists of five small overlapping stratovolcanoes constructed along a WNW-ESE line within a large 9 x 13.5 km caldera. The caldera formed about 38,000-40,000 years ago accompanied by the eruption of about 100 km3 of tephra. The massive complex includes 11 summit and 30 flank craters, some of which contain acid or freshwater crater lakes; three major rift zones cut the complex. Another Holocene stratovolcano is located on the SW flank. Activity during the Holocene was characterized by frequent mild-to-moderate explosive eruptions along with a half dozen episodes of major lava extrusion. Early Holocene explosive activity, along with lava flows filled in much of the caldera. Quiescent periods became longer between 6000 and 2000 years ago, after which the activity was mainly explosive. About 600-650 years ago intermittent strong explosions and lava flow effusion accompanied frequent mild eruptions. Historical eruptions have consisted of moderate Vulcanian and phreatic explosions.
Sources: Kamchatkan Experimental and Methodical Seismological Department, Pravda News