Geologic Background:
Summit of seamount is large flat area at depth
of about 100 meters with pinnacles rising to within 30
meters of surface.
Historic Activity:
- First discovered by hydrophones in May 1967.
- Based on acoustic signals there have been more than
20 eruptive events since 1977 with 8 of them occurring
from June 1987 to April 1988.
Recent Activity:
- Eruptive event from Sept. 2 to Sept. 18, 1988
consisting of shallow submarine explosions of moderate
intensity.
- Seismicity produced by activity at Macdonald Seamount
was substantially more vigorous in 1987 and 1988 than in
previous years since 1977.
- Activity was observed from Jan. 19 to Jan. 25,
1989.
Data Sources:
- Smithsonian's SEAN Bulletin (V. 8, No. 4 to V. 14,
No. 1).
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