Report on Minami-Hiyoshi (Japan) — April 1980
Scientific Event Alert Network Bulletin, vol. 5, no. 4 (April 1980)
Managing Editor: David Squires.
Minami-Hiyoshi (Japan) No water discoloration seen since March 1978
Please cite this report as:
Global Volcanism Program, 1980. Report on Minami-Hiyoshi (Japan) (Squires, D., ed.). Scientific Event Alert Network Bulletin, 5:4. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198004-284131.
23.5°N, 141.935°E; summit elev. -107 m
All times are local (unless otherwise noted)
The Japan Maritime Safety Agency continues frequent monitoring flights over three known submarine volcanoes. [Discolored water at Minami-hiyoshi was not seen during August 1979-March 1980 (see table 1 below).]
Geologic Background. Periodic water discoloration and water-spouting have been reported over this submarine volcano since 1975, when detonations and an explosion were also reported. It lies near the SE end of a coalescing chain of youthful seamounts, and is the only historically active vent. The reported depth of the summit of the trachyandesitic volcano has varied between 274 and 30 m. The morphologically youthful seamounts Kita-Hiyoshi and Naka-Hiyoshi lie to the NW, and Ko-Hiyoshi to the SE.
Information Contacts: JMSA, Tokyo; JMA, Tokyo.