No water discoloration seen in 1990

No discolorations were observed at . . . Fukujin . . . during 1990.

Information Contacts: Hydrographic Department, JMSA.

Information is preliminary and subject to change. All times are local (unless otherwise noted)

January 1974 (CSLP 11-74)

Explosive activity detected by hydrophone began in September 1973

Card 1778 (21 January 1974) Explosive activity detected by hydrophone began in September 1973

"So far hydrophone records from Wake and Midway Islands indicate a sustained submarine volcanic eruption near 22°N, 144°E. Eruption noise was first detectable about 1800 GMT, 25 September 1973 and was continuing unabated as of 14 January 1974. The activity was explosive. The indicated location is about 40 km N of a similarly detected submarine eruption site of 6-7 July 1972." The subject area is approximately 250 miles (400 km) SE of Iwo Jima, and 580 miles (935 km) N of Guam.

Information Contacts: Rockne Johnson, Hawaii Institute of Geophysics, Honolulu, Hawaii, USA.

February 1974 (CSLP 11-74)

Steam plume seen by fishing boats; active bubbling and water discoloration

Card 1794 (11 February 1974) Steam plume seen by fishing boats; active bubbling and water discoloration

The following information was reported from fishing boats and the Maritime Self Defence Force on a submarine eruption between the Volcano Islands and Mariana Islands. Location: 21°55'30"N and 143°26'30"E, about 400 km S of Minami-iozima. It is called Hukuzin-okaba, a submarine, but shallow site.

A fishing boat, the Tatumimaru No. 18 reported a submarine eruption on 18 January as follows: 2-3-mile-high white smoke with a strong smell of sulfur rose from several points on the sea-surface around 0600 JST. Another fishing boat, the Anyomaru No. 10 also reported on the same day: 2-3-mile-high white smoke was seen in the same area starting in the early morning. One water plume (about 70 m across and 20 m high) shot up with rumblings at about 1125 JST on 18 January.

According to an aerial observation made by the Maritime Self Defence Force at 1040 JST on 25 January, active bubbling under the sea-surface from four points in an area about 100 m in diameter was observed at the point 21°52'N and 143°33'E, about 320 km S of Minami-Iozima. A discolored belt on the sea-surface, about 10 km long and 600 km wide, was floating westward.

Information Contacts: Seismological Division, Japan Meteorological Agency.

March 1974 (CSLP 11-74)

Underwater sound signals essentially terminated on 26 January

Card 1832 (29 March 1974) Underwater sound signals essentially terminated on 26 January

R.H. Johnson reported that "underwater sound signals from the eruption near 22°N, 144°E, essentially terminated on 26 January about 1600 GMT, although sporadic signals were detected on 27 and 28 January. Hydrophone records to 2000 GMT 1 February show no sign of a resumption of submarine activity."

The Japan Meteorological Agency noted that "according to a report from a fishing boat, Zintoku-maru No. 12, on 22 February a submarine eruption with a 1-m-high plume and a 2-km-long discolored belt on the sea-surface was observed at a point 400 km SE of Iozima."

Information Contacts: R.H. Johnson, Hawaii Institute of Geophysics, USA; Seismological Division, Japan Meteorological Agency.

January 1977 (NSEB 02:01) Cite this Report

Possible submarine eruption in March 1974

[A table of possible submarine eruptions based on aerial observations of water discoloration by the Japanese Maritime Safety Agency included an entry for 21.93°N, 143.46°E, on 20 March 1974. This location is just E of Fukujin]

Information Contacts: AFP; U.S. Defense Mapping Agency.

February 1977 (NSEB 02:02) Cite this Report

Zone of discolored water observed from the air

A yellowish-green zone of discolored water was observed from the air at this site on 3 December 1976. By 11 February 1977, activity had declined. The strongest recent activity occurred on 15 October 1973, when explosions intermittently ejected a "smoke" cloud containing blocks to 50-80 m above the ocean surface. Explosions were reported by fishing boats on 18 January and 20 February 1974 and discoloration of water on several other occasions.

The JMSA ship Syoko visited the area in August 1976 and reported a conical submarine volcano rising 3,000 m from the ocean floor. A depth of 3 m was recorded by a fishing boat on 20 March 1974.

Information Contacts: JMA, Tokyo; Japanese Press.

May 1978 (SEAN 03:05) Cite this Report

Discolored water in October 1977 and January 1978

Discolored water was seen 14 October and 10, 24, and 26 January. Five greenish circular spots were observed on 10 January and eruptions occurred about once every 2 minutes on 24 January.

Information Contacts: JMA, Tokyo.

July 1979 (SEAN 04:07) Cite this Report

Occasional water discoloration during 1978-79

Discolored water was occasionally visible over Fukujin, previously called Hukuzin-oka-no-ba, in 1977, 1978, and 1979. [Discolored water was specifically noted, in an included table of observations during January 1978-July 1979, on 10, 24, 25, and 26 January 1978, 24 March 1978, 25 August 1978, 26 April 1979, and 12 July 1979.]

Information Contacts: JMA, Tokyo.

April 1980 (SEAN 05:04) Cite this Report

Water discoloration in late 1979 and early 1980

The Japan Maritime Safety Agency continues frequent monitoring flights over three known submarine volcanoes. [Discolored water at Fukujin was seen during October 1979-March 1980 (see table 1 below).]

Information Contacts: JMSA, Tokyo; JMA, Tokyo.

November 1980 (SEAN 05:11) Cite this Report

Water discoloration seen on 12 May 1980

The Japan Maritime Safety Agency (JMSA) continues frequent monitoring flights over several known submarine volcanoes. [Discolored water at Fukujin was seen during May 1980 (see table 1 below).]

Information Contacts: JMSA, Tokyo; JMA, Tokyo.

December 1980 (SEAN 05:12) Cite this Report

No seawater discoloration seen in November-December 1980

The Japanese Maritime Safety Agency (JMSA) continues frequent aerial monitoring of several known submarine volcanoes. [Discolored water was not seen at Fukujin during November-December 1980 (see table 1 below).]

Information Contacts: JMSA, Tokyo; JMA, Tokyo.

October 1981 (SEAN 06:10) Cite this Report

Water discoloration seen in January 1981, but then none through October

The Japan Maritime Safety Agency (JMSA) continues frequent monitoring flights over several known submarine volcanoes. [Discolored water was specifically noted, in an included table of observations, on 7 and 8 January, but not again through October 1981 (see table 1 below).]

Information Contacts: JMSA, Tokyo; JMA, Tokyo.

September 1982 (SEAN 07:09) Cite this Report

Occasional water discoloration every year since 1977

JMSA [and JMSDF have] continued frequent monitoring flights over several known submarine volcanoes (table 1). Discoloration has been seen occasionally over Fukujin each year since 1977. Analysis of Landsat satellite multi-spectral scanner data revealed discolored water there in January 1982, after a year of quiescence.

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

Information Contacts: JMSA, Tokyo; JMA, Tokyo.

March 1984 (SEAN 09:03) Cite this Report

No water discoloration seen since December 1982

Frequent monitoring of several known submarine volcanoes has continued. . . . No discolored water has been observed at Fukujin since December 1982.

Information Contacts: JMA, Tokyo.

November 1985 (SEAN 10:11) Cite this Report

No water discoloration observed, December 1983-December 1985

JMSA has continued frequent aerial monitoring of several known submarine volcanoes. Volcanic activity has often been observed at Fukutoku-okanoba during overflights since late 1983, but no water discoloration has been seen at Kasuga, Nikko, or Fukujin.

Information Contacts: JMA, Tokyo.

December 1990 (BGVN 15:12) Cite this Report

No water discoloration seen in 1990

No discolorations were observed at . . . Fukujin . . . during 1990.

Information Contacts: Hydrographic Department, JMSA.