Geologic Background
Kliuchevskoi is Kamchatka's highest and most
active volcano. Since its origin about 7,000 years ago,
this symmetrical basaltic stratovolcano has produced
frequent moderate volume explosive and effusive eruptions
with no major periods of inactivity. More than 100 flank
eruptions have occurred during the past 3,000 years. The
morphology of its 700-m-wide summit crater has been
frequently modified by historical eruptions.
Historic Activity:
- More than 80 eruptions have been reported from
Kliuchevskoi since 1697.
- Historical eruptions have originated primarily from
the summit crater, but have also included major explosive
and effusive eruptions from flank craters.
Recent Activity:
- A NE flank eruption began on March 8, 1983 and
continued into June. As many as 15 lava flows were
simultaneously active, some reaching 5 km in length.
- From March 1984 to Jan. 1985, short lava flows from
crater and tephra plumes 1 to 2 miles high. Aug. 1985 to
Jan. 1986; summit gas and ash explosions followed by lava
fountaining and lava flows from summit and NW flank
vents. In Dec. 1985, a NW flank explosions fed eruptive
columns which reached 6 miles high and melted snow on
flanks causing mudflows. Dec. 1986 to Feb. 1987, gas and
ash explosions and lava flows. Simultaneous summit and
flank eruptions began April 6, 1988.
- Explosive activity from summit and flank vents
emmitted ash and lava from Oct. 1989 to Jan. 1990. Large
summit eruption began on Jan. 29. and continued into
March with tephra deposits and basaltic lava flow.
- A small eruption from the summit crater occurred at
1033 on April 8, 1991. Space Shuttle photographed a plume
on April 29, 1991. A weather satellite showed a plume on
June 24, 1991.
- Distinct, single explosions produced ash columns
rising 1000 m on January 25-26, 1992. A January 29 Space
Shuttle photograph showed a steam plume rising from the
apparently ash-covered summit region. Several explosions
were observed on May 13/14, 1992 which ejected ash clouds
to 1000 m above the summit.
- An increase in activity at Kliuchevskoi was noted in
mid-March 1993, after a short period of repose. Increased
volcanic tremor occurred after mid-April. Three ash
explosions from the summit crater occurred on May 10th
Tremor amplitude had decreased by May 19, 1993.
Steam-and-ash explosions continued into June. Lava
fountains, characteristic for this volcano, were observed
rising 400 m above the crater rim on the night of July
4-5. An explosive eruption on July 15 sent an ash cloud
to an approximate altitude of 7.8 km. A second eruption
on July 16 set ash to 6 km. Activity was continued into
early September, but lava had stopped flowing from the
crater by August 13. On Sept. 9, the gas-and-ash plume
rose 200 m above the crater and extended SE for about 15
km. Continued small gas-and-ash plumes and small
explosions into Nov.
- Weak seismicity, fumarolic activity, and volcanic
tremor continuing into May 1994. Small phreatic
explosions in June. Seismic activity in July and August.
Eruption began on Sept. 8, with eruption column to
several km altitude and lava fountains and flows. Similar
activity continued through the rest of Sept. and then
entered the paroxysmal phase on Oct. 1 with an eruption
column reaching 15 to 20 km altitude. Eruption appeared
to end by Oct. 4 when only fumarolic activity was
observed. Continuous tremor into early Nov. and then a
moderate explosive eruption began on Nov. 23, 1994 and
was continuing in mid-January 1995.
- Reports on volcanoes in Kamchatka by the Kamchatkan
Volcanic Eruptions Response Team were suspended in Dec.
1994, due to lack of funding by the Russian government.
Occasional reports continued from other sources.
- Normal seismic activity was reported in June to
November 1996. During December seismicity increased and
ash-and-steam plumes up to 3 km tall were observed.
- 1997 began with increased seismicity and ash-and
steam plumes up to 4 km tall which continued through
April. Continued gas-and-steam plumes through December
with occasional ash-and-steam plumes upto 1 km tall.
- Elevated seismicity and large steam plumes in 1999.
Series of ash explosions in May. Fumarolic activity
continued through end of year.
- Fumarolic activity in January 2000. Continued
fumarolic activity and increased seismicity in early
September were followed by gas-and-ash explosions in in
mid-September.
- Consisten gas-and-steam emissions and high seismicity
in April 2001
Data Sources:
- Smithsonian's SEAN Bulletin (V. 3, No. 7 to V. 13,
No. 4)
- Global Volcanism Network (V. 15, No. 1 to V. 25, No.
9).
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