Geologic Background:
Kavachi, one of the most active submarine
volcanoes in the SW Pacific, occupies an isolated
position in the Solomon Islands far from major aircraft
and shipping lanes. Kavachi, sometimes referred to as
Rejo te Kvachi ("Kavachi's oven"), is located south of
Vangunu Island only 30 km north of the site of subduction
of the Indo-Australian plate beneath the Pacific plate.
The shallow submarine basaltic-to-andesitic volcano has
produced ephemeral islands up to 150 m long at least
eight times since its first recorded eruption during
1939. The roughly conical volcano rises from water depths
of 1.1-1.2 km on the north and greater depths to the
south.
Historic Activity:
- At least 17 submarine eruptions from 1939 (first
reported activity) to 1980 have been reported.
- Nine eruptions have built temporary islands.
Recent Activity:
- During April to June 1982 a 3.5 km long plume was
ejected but no island formed.
- During late December 1985 explosions at a rate of one
per minute were ejecting material to heights of 200 to
300 meters. Activity continued at various levels of
intensity until late February 1986. During July 1986
activity was reported on at least 6 days.
- New island formed in 1991. Eruption began in May 1991
and ended by mid June, and the island was eroded away by
the end of the month. Exact location was uncertain at
first due to conflicting reports. Location was finally
established as being roughly 3 km NE of Kavachi's
summit.
- On Jan. 16, 1997, a Solair pilot reported continuous
ejection of mud and hot ash up to 2.1 km altitude.
Eruption was continuing the next day but had stopped by
Jan. 29.
- Eruption on May 14, 2000
Data Sources:
- Smithsonian's SEAN Bulletin (V. 1, No. 11 to V. 11,
No. 7)
- Global Volcanism Network (V. 16, No. 4 to V. 25, No.
3).
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