Global Volcanism Program | Report on Minami-Hiyoshi (Japan)

Report on Minami-Hiyoshi (Japan) — September 1982

Scientific Event Alert Network Bulletin, vol. 7, no. 9 (September 1982)
Managing Editor: Lindsay McClelland.

Minami-Hiyoshi (Japan) No water discoloration seen since March 1978

Please cite this report as:

Global Volcanism Program, 1982. Report on Minami-Hiyoshi (Japan) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 7:9. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198209-284131

Minami-Hiyoshi

Japan

23.5°N, 141.935°E; summit elev. -107 m

All times are local (unless otherwise noted)

JMSA [and JMSDF have] continued frequent monitoring flights over several known submarine volcanoes (table 1). No discolored sea water has been observed near Minami-Hiyoshi since March 1978.

Table 1. Volcanic activity at three sites in the Volcano Islands, January 1978-December 1982, detected by JMSA and JMSDF monitoring flights. Activity indicated as D = Discolored water; N = No discolored water, - = No overflight, ? = not reported. This table combines data from 4:7, 5:4, 5:11, 5:12, 6:10, and 7:9, plus additional 1982 data not published in the Bulletin.

Date	Fukutoku-Okanoba	Minami-Hiyoshi	Fukujin
10 Jan 1978	D	N	D
24 Jan 1978	D	N	D
25 Jan 1978	D	-	D
26 Jan 1978	-	D	D
23 Feb 1978	D	D	N
24 Mar 1978	D	D	D
13 Apr 1978	D	N	N
25 May 1978	D	N	N
28 Jun 1978	D	-	-
29 Jun 1978	D	N	N
25 Aug 1978	D	N	D
24 Oct 1978	N	N	N
15 Nov 1978	D	-	-
16 Nov 1978	D	N	N
14 Dec 1978	D	N	N
11 Jan 1979	D	-	-
24 Jan 1979	D	N	N
08 Feb 1979	D	N	N
27 Mar 1979	D	[N]	-
26 Apr 1979	D	N	D
15 Jun 1979	N	N	N
11 Jul 1979	N	-	-
12 Jul 1979	D	N	D
24 Aug 1979	N	N	-
09 Sep 1979	D	-	-
13 Sep 1979	D	N	N
25 Oct 1979	D	N	D
08 Nov 1979	D	N	D
12 Dec 1979	D	N	D
29 Jan 1980	-	-	D
15 Feb 1980	D	N	D
19 Mar 1980	D	N	D
24 Apr 1980	D	N	N
12 May 1980	D	-	D
16 Jun 1980	D	N	N
07 Jul 1980	D	-	-
08 Jul 1980	D	N	N
14 Jul 1980	D	N	N
18 Aug 1980	N	N	N
04 Sep 1980	N	N	N
21 Oct 1980	N	N	N
14 Nov 1980	D	N	N
18 Dec 1980	D	N	N
07 Jan 1981	-	-	D
08 Jan 1981	-	-	D
09 Jan 1981	D	N	N
29 Jan 1981	D	-	-
12 Feb 1981	D	[-]	-
20 Feb 1981	D	[N]	N
12 Mar 1981	D	[-]	-
13 Mar 1981	D	N	N
16 Mar 1981	D	N	N
20 Apr 1981	D	N	N
17 Jun 1981	N	N	N
16 Jul 1981	D	-	-
17 Jul 1981	D	[N]	[N]
22 Jul 1981	D	N	N
17 Aug 1981	D	N	N
17 Sep 1981	D	N	N
19 Oct 1981	N	N	N
11 Nov 1981	N	N	[-]
21 Dec 1981	D	N	N
12 Jan 1982	-	-	D
19 Jan 1982	D	N	D
09 Feb 1982	D	N	N
28 Feb 1982	D	-	-
16 Mar 1982	D	N	D
01 Apr 1982	D	-	N
02 Apr 1982	D	N	N
16 Apr 1982	D	N	N
14 May 1982	D	N	N
16 Jun 1982	D	N	N
22 Jun 1982	D	-	-
13 Jul 1982	D	?	N
20 Aug 1982	D	?	N
27 Sep 1982	D	?	N
13 Oct 1982	D	?	N
17 Nov 1982	D	?	N
15 Dec 1982	D	?	D

Geological Summary. Periodic water discoloration and water-spouting have been reported over the Minami-Hiyoshi submarine volcano since 1975, when detonation sounds and an explosion were also reported. It lies near the SE end of a coalescing chain of youthful seamounts, and is the only vent with recorded activity. 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.