Geologic Background:
Loihi is the youngest member of the Hawaiian
volcanic chain, rising to slightly higher than 980 m
below sea level. The summit platform includes 2
well-defined pit craters, sediment-free glassy lava, and
low-temperature hydrothermal venting. An arcuate chain of
small cones on the W edge of the summit extends N and S
of the pit craters and merges into the crests of Loihi's
prominent N and S rift zones. Continued volcanism is
expected to eventually build a new island at Loihi; time
estimates for the summit to reach the surface range from
roughly 10,000 to 100,000 years.
Recent Activity:
- No activity has been observed due to depth but
dredging and remote cameras have have revealed very fresh
volcanic rocks.
- Earthquake swarms have been recorded at Loihi in
1971-1972, 1975, November 1984-January 1985 and on
September 20, 1986. These swarms may be related to
volcanic eruptions.
- Intrusive event during mid-January 1989.
- Strong earthquake swarm suggesting magma movement
occurred during March 11-19, 1990.
- Earthquake swarms in December 1991, October 1993,
April 1995, and September 2001.
Data Sources:
- Smithsonian's SEAN Bulletin (V. 10, No. 1; V. 11, No.
9; and V. 14, No. 1)
- Global Volcanism Network (V. 15, No. 3 to V. 26, No.
9).
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