Geologic Background:
The high, isolated massif of Shiveluch volcano
(also spelled Sheveluch) rises above the lowlands NNE of
the Kliuchevskaya volcano group. The 1100 cu km Shiveluch
is one of Kamchatka's largest and most active volcanic
structures. The summit of roughly 65,000-year-old Strary
Shiveluch is truncated by a broad 9-km-wide
late-Pleistocene caldera breached to the south. Many lava
domes dot its outer flanks. The Molodoy Shiveluch lava
dome complex was constructed during the Holocene within
the large breached caldera; Holocene lava dome extrusion
also took place on the flanks of Strary Shiveluch. At
least 60 large eruptions of Shiveluch have occurred
during the Holocene, making it the most vigorous
andesitic volcano of the Kuril-Kamchatka arc. Widespread
tephra layers from these eruptions have provided valuable
time markers for dating volcanic events in Kamchatka.
Frequent collapses of dome complexes, most recently in
1964, have produced debris avalanches whose deposits
cover much of the floor of the breached caldera.
Historic Activity:
- Eruptions in 1854, 1879-1883, 1897-1898, 1905,
1928-1930, 1944-1950, and 1964.
- The largest historical eruptions occurred in 1854 and
1964.
- The 1854 eruption destroyed a cone that had grown
within the older caldera, formed another caldera, and
caused a large debris avalanche.
- A violent explosive eruption in 1964 in turn
destroyed a younger dome complex, creating a new caldera
1.5 x 3 km.
- Activity in the crater formed by the major 1964
eruption was only fumarolic until 1980.
Recent Activity:
- 1980 to 1981, lava extrusion and explosive activity
associated with extrusive dome.
- A period of phreatic explosive activity started in
1984, forming vents near the dome's summit.
- A funnel-shaped crater 80 m in diameter formed in
1987 by coalescence of several smaller vents.
- On April 8, 1991 an explosive eruption began in the
dome area, ejecting an ash cloud 6-8 km high that was
visually tracked 40 km to the SE.
- Another explosive burst began on March 18, 1993.
Earthquake activity increased in early April. The
climactic eruption began the morning of April 22, 1993.
The eruption cloud reached an altitude of 20 km by
mid-afternoon. Pyroclastic flows down the flanks of the
volcano. Explosive eruptions continued to May 3. A
extrusive dome began forming in early May.
- Large ash eruptions in April 1999 with activity
continuing through end of year.
- Intermittent ash explosion from January to March
2000. Explosive eruptions from June 30 to July 3.
Continued volcanic unrest through November with partial
dome collapse. Increased activity in December.
- Activity continued to increase in early 2001. A new
dome began to form on May 7. Eruptions in late June sent
plumes to about 8 km altitude. Pyroclastic flows on July
15 and an explosion on August 23.
Data Sources:
- Smithsonian's SEAN Bulletin (V. 9, No. 5 to V. 13,
No. 4)
- Global Volcanism Network (V. 15, No. 3 to V. 26, No.
8).
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