Report on Suwanosejima (Japan) — September 1976

Natural Science Event Bulletin, vol. 1, no. 12 (September 1976)
Managing Editor: David Squires.

Suwanosejima (Japan) Pilots note unusually high "smoke" columns

Please cite this report as:

Global Volcanism Program, 1976. Report on Suwanosejima (Japan). In: Squires, D (ed.), Natural Science Event Bulletin, 1:12. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.NSEB197609-282030.

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Suwanosejima

Japan

29.638°N, 129.714°E; summit elev. 796 m

All times are local (unless otherwise noted)


TOA (domestic) airline pilots noted unusually high "smoke" columns from On-take summit crater in July (table 1). [This crater name, used in original SEAN reports (and Volcanoes of the World), should not be confused with the volcano of the same name on Honshu.]

Table 1. Summary of explosions and other observations from Suwanose-jima, October 1975-December 1985. White vapor was emitted during days not listed in the table for 1977-78. "NVO" for 1979-October 1982 data indicates no visual observation due to bad weather. Numbers in parentheses are the local observation times. Dashes indicate no data provided or unknown. Data have been combined from monthly Bulletin tables and JMA has added data missing from original reports, including May 1984 and 1985. Courtesy of JMA.

[Skip text table]
    1975       Plume     Activity
             Height (m)

    Oct 04      700      Sometimes moderate explosions
        05     1000      Sometimes large explosions, ashfall
        06     1500      Large explosions, ashfall
        07      --       Explosion
        08     1000      Large explosion
        09      500      Explosion
    Nov 09     1500      Large explosion
        10      600      Explosion
        19      500      Large explosion
    Dec 07      200      Sometimes small explosions
        21      700      Frequent large explosions
        21      400      Remarkable incandescent column, frequent large
                           explosions
        23      700      Explosion
        24      400      Sometimes large explosions
        25      700      Explosion
        26     1000      Frequent large explosions
        27      700      Large explosion
        28      700      Moderate explosion
        31      400      --

    1976
    Jan 08      300      Large explosion
        24     1000      Ashfall
        25     1000      Large explosion, ashfall
        26      --       Ashfall
        27      500      Large explosion, ashfall
        28-29  1500      --
    Feb 14      --       Moderate explosion
        15      800      Moderate explosion, ashfall
        16      --       Sometimes explosion sounds, ashfall
        17      --       Sometimes explosion sounds
        18      300      Sometimes explosion sounds
        19      700      Explosion
        20      500      Moderate explosion
        26      --       Explosion
    Mar 12      500      Frequent large explosions
        13      700      Frequent large detonations
        14      500      Sometimes moderate explosions
    Apr 13      --       Moderate detonation
        14      300      Ashfall
        15      300      Ashfall, moderate explosion
        16     1000      Ashfall
    May 10      500      Explosion
    Jul 03     4200      Moderate detonation
        04   3600-4200   TOA airline pilot observed ashcloud
        07     3600      TOA airline pilot observed ashcloud
        23     3000      Explosion, large ash cloud, ashfall
        24     3000      Explosion, ashfall
    Oct 04      500      Ashfall
        12      500      Ashfall
    Nov 01      --       Ashfall

    1977
    Jan 11     1200      One explosion
    Mar 19-21   700      Ash ejection and ashfall
        24-25   --       Two explosions
    Apr 01-03  1000      One explosion, ash ejections
        10-11  3000      Ash ejections and ashfall
        14-20  1000      Two explosions, ash ejections & ashfall
        27-29  3000      Explosions, ash ejections
    May 08      --       One explosion
        13-18  2000      Several explosions, ashfall
        26     1000      One explosion
    Jun 03-05  3000      Frequent explosions, incandescent column, ashfall
        21-22  3000      Frequent explosions
    Jul 09-10  4000      Ash ejections, one explosion
        23      --       Explosions
    Aug 08-10  3000      Frequent explosions, incandescent ejecta
    Sep 10-15  3000      Frequent explosions, ash ejections, ashfall
        18     3000      Ash ejections and ashfall
    Oct 23     1000      One ash ejection
        26-30  2000      Ash ejections
    Nov 14      --       One explosion
        19     2000      Ash ejections
    Dec 06      --       One explosion

    1978
    Jan 23      --       Three explosions
    Mar 19      500      Two ash ejections
        22-25  1000      Ash ejections
    Apr 09     1000      Ash ejections
        19-22  3000      Ash ejections and ashfall
    May 01-03   500      Ash ejections and ashfall
        31      500      Frequent explosions, incandescent column
    Jun 01      500      Frequent explosions, incandescent column, ashfall
        16-19   --       Frequent explosions
    Jul 02-05   700      Frequent explosions, incandescent column, ashfall
        19-21  3000      Ash ejections and ashfall
    Aug 07-10  3000      Frequent explosions, incandescent column, ashfall
        24     2000      Ash ejections and ashfall
    Sep 07     3000      Frequent explosions, ashfall
        17      --       One explosion
        23-24   700      Frequent explosions, incandescence
    Oct 10-12  5000      Frequent explosions, ashfall
        24-28  3000      Frequent explosions, incandescence, ashfall
    Nov 06-10   700      Explosions, incandescence, ashfall
        19-22   500      Explosions, incandescent column, ashfall
    Dec 04-05   300      Explosions

    1979
    Feb 06      500      Explosions, incandescence
        14-15   500      Explosions, ashfall
        19      500      One explosion
        22      --       One explosion
    Mar 11-13   500      Four explosions
    Jun 05      --       Incandescent column, explosions
    Jul 20      500      Seven explosions, ash emissions
        21      200      Ash emissions
    Sep 05-06  2000      Frequent, strong explosions, incandescent columns,
                           ashfall to sea
        07     1000      Ash emissions
        08      800      Ash emissions
        09     2000      Frequent explosions
        12     1000      Ten explosions
    Dec 10     1500      Explosions, incandescent blocks, reflected glow
        11      --       Ash emissions
        12      --       "Flames" in crater
        18      300      Three explosions

    1980
    Feb 05-06  1500      About 10 explosions, incandescent column
    Mar 21-22  1000      Many explosions
    Apr 25-26  1500      Explosions: ashfall on inhabited areas
    May 13      --       Three explosions
        18      500      Six explosions; persistent ash ejection
    Jun 04-05   500      More than 25 explosions
    Jul 16-19   --       Many explosions
    Aug 03-08  1500      Several tens of explosions; incandescent column
        21-23  1000      More than 20 explosions; incandescent column
    Sep 08-09  1000      More than 1000 explosions
        20      --       Three explosions
        24-27  2000      More than 1000 explosions
    Oct 25-27   500      Persistent ash ejection
    Nov 08-10  1500      More than 1000 explosions
        29      500      Persistent ash ejection
    Dec 13      --       Explosions

    1981
    Jan 04-08  100-1000  Continuous ash cloud
        29      500      Ten explosions
        30      300      Two explosions
        31      NVO      Two explosions
    Feb 12     1000      One explosions
        20     1000      Three explosions
        26      500      16 explosions
    Mar 17     1000      20 explosions
    Apr 15      NVO      Many explosions
        16      NVO      16 explosions
        26      500      Many explosions
    May 14      500      Ten explosions
    Jun 12     1500      Three explosions
        13      NVO      Two explosions
        15      NVO      Three explosions
        16      NVO      Three explosions
        29-30   --       Many explosions
    Jul 01-04   NVO      Many explosions
        05      500      Ten explosions
        06      NVO      Ten explosions
        13      NVO      Three explosions
        14     2000      Many explosions
        15      NVO      Six explosions
    Nov 26      NVO      Many explosions
        27     1500      Many explosions
    Dec 13      500      40-50 explosions; rumbling
        14      500      Many explosions; rumbling
        15      500      30-40 explosions; rumbling
        16      500      Two explosions
        23      NVO      Two explosions

    1982
    Jan 02     1500      Four explosions
        23     1000      2-3 explosions/hour
        25      200      Ten explosions
        26      500      Many explosions
        27      300      12 explosions
        28      300      Three explosions
    Feb 03      NVO      Five explosions
        06      200      Five explosions
        07      200      One explosion
        08      200      One explosion
        13     1000      One explosion; rumbling
        14-15   500      Many explosions; rumbling
        16-17   NVO      Many explosions; rumbling
        18      500      Many explosions; rumbling
        19      NVO      Six explosions
        22     1000      Three explosions
        23      NVO      Four explosions
        24      NVO      Three explosions
        25     1000      Seven explosions; rumbling
        26      500      Five explosions
    Mar 09     1000      Many explosions; rumbling
        10     1000      Many explosions; rumbling
        11      500      Ten explosions
        28      NVO      Ten explosions; rumbling
        29      NVO      20-25 explosions; rumbling
        30     1000      Four explosions
        31      NVO      Six explosions
    Apr 01     1000      Two explosions
        02     1000      Ten explosions
        03      NVO      Three explosions
        15      500      18-20 explosions; rumbling
        17      500      5-6 explosions/hour
        18      NVO      2-3 explosions/hour
        19      NVO      Ten explosions; rumbling
    May 05      200      One explosion
        06     1000      Many explosions; rumbling
        27     1000      One explosion
    Jun-Jul     NVO      Quiet
    Aug 16     1000      Four explosions
        17      500      Four explosions
    Sep 02      500      Five explosions
        16      NVO      Many explosions
        25      200      Nine explosions
        26      200      Three explosions
    Oct 05      500      Three explosions; rumbling
        06      NVO      Six explosions
        07      NVO      Seven explosions
        08      NVO      Ten explosions; rumbling
        09      300      Seven explosions
        17      NVO      One explosions
    Nov 03      500      3-4 explosions/hour       (0500-2200 LT)
        04      500      5-6 explosions/hour       (0500-2200 LT)
        05      500      5-6 explosions/hour       (0700-2100 LT)
        06      500      3 explosions/hour         (0500-2200 LT)
        07      500      1-2 explosions/hour       (0600-2200 LT)
        23      500      Five explosions           (0900-1300 LT)
    Dec 15      500      Ashfall
        17     1000      15-16 explosions          (1300-2000 LT)
        18      500      Ashfall
        19     1000      2-3 explosions/minute     (0900-2100 LT)
        20     1000      1-2 explosions/5 minutes  (0600-2100 LT)
        29      500      Two explosions            (1000-1300 LT)

    1983
    Jan 17      500      4-6 explosions/minute     (0630-0800 LT)
                         3-4 explosions/hour       (0800-2000 LT)
        18    Unknown    3-5 explosions/hour       (0600-2200 LT)
        19    Unknown    15-20 explosions          (0600-1700 LT)
        28      500      25-30 explosions          (1700-2200 LT)
        29      700      2-3 explosions/minute     (0500-1800 LT)
                         4-5 explosions/hour       (1800-2200 LT)
        30     1000      4-5 explosions/hour       (0500-1600 LT)
    Feb 10      200      A few explosions
        11      500      1-2 explosions/minute     (1900-2100 LT)
        26     1000      5-6 explosions/minute     (1530-2300 LT)
        27     1000      Ten explosions            (0500-1200 LT)
    Mar 04    Unknown    One explosion
        11     1000      2-3 explosions/minute     (1400-2300 LT)
        12    Unknown    12 explosions             (0600-1200 LT)
        13      --       Three explosions          (0800-1200 LT)
    Apr 28    Unknown    3-5 explosions/minute     (1400-1600 LT)
        29      500      Three explosions          (1500-1900 LT)
    May 08      200      Six explosions            (0700-1500 LT)
        11      200      Three explosions          (1400-1500 LT)
        12      200      Three explosions          (1300-1500 LT)
    Jun 08     1500      Seven explosions          (1400-1900 LT)
        09     1500      Four explosions           (1500-1800 LT)
        10      500      Seven explosions          (0900-2000 LT)
    Jul 05-06   --       Incandescent column       (2100-0300 LT)
        27      500      Two explosions            (1200-1730 LT)
    Sep 30     1500      7-9 explosions/hour       (0500-0900 LT)
    Oct 01     1000      17 explosions             (0500-0900 LT)
        17    Unknown    15 explosions             (0600-1800 LT)
        18     1000      Five explosions           (0530-1130 LT)
        27      500      Rumbling                  (1400-2300 LT)
        28     1000      Rumbling                  (0500-1330 LT)
        29     1000      Rumbling                  (0500-  ?  LT)
    Nov 22      500      10-15 explosions/minute   (1000-2200 LT)
        23      500      15-20 explosions/minute   (0920-1100 LT)
                         15-20 explosions/minute   (1400-1700 LT)
        25      300      16 explosions             (0600-1800 LT)
    Dec 03      500      2-10 explosions/minute    (1500-2300 LT)
        04      300      Six explosions            (1000-2200 LT)
        18      500      2-3 explosions/minute     (0400-1500 LT)
                         10 explosions             (1500-2200 LT)
        19      500      15-20 explosions/minute   (0500-0900 LT)
                         20 explosions             (1500-2300 LT)
        20      500      2-3 explosions/minute     (0400-0700 LT)
                         20 explosions             (0700-2100 LT)

    1984
    Jan 02      300      13 explosions             (0500-2000 LT)
        26      300      13 explosions             (0600-2200 LT)
        27      500      5-7 explosions/hour       (1600-2200 LT)
        28      500      30-40 explosions/hour     (0800-2300 LT)
        29      500      Seven explosions          (0500-1200 LT)
        30      500      10 explosions             (0400-1500 LT)
    Mar 14-16   --       4-5 explosions/minute
        18      --       10 explosions             (0500-2300 LT)
    Apr 12     1000      Seven explosions          (2100-2300 LT)
        15      --       Seven explosions          (0730-1300 LT)
                         5-6 explosions            (1700-2200 LT)
        16      --       Six explosions            (0700-1700 LT)
        17      --       12 explosions             (0500-1000 LT)
        18      --       Three explosions          (0600-1000 LT)
    May 15      --       12-13 explosions

    1985
    Jun 28     2000      Airplane pilot saw the ash cloud,
                           light ashfall
    Aug 03      --       Airplane pilot saw the ash cloud
    Sep 14-15   --       Frequent explosion sounds
    Oct 01      --       Airplane pilot saw the ash cloud
    Nov 17-21   --       Frequent explosion sounds
    Dec 05-06   --       Frequent explosion sounds

Geologic Background. The 8-km-long, spindle-shaped island of Suwanosejima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two historically active summit craters. The summit of the volcano is truncated by a large breached crater extending to the sea on the east flank that was formed by edifice collapse. Suwanosejima, one of Japan's most frequently active volcanoes, was in a state of intermittent strombolian activity from Otake, the NE summit crater, that began in 1949 and lasted until 1996, after which periods of inactivity lengthened. The largest historical eruption took place in 1813-14, when thick scoria deposits blanketed residential areas, and the SW crater produced two lava flows that reached the western coast. At the end of the eruption the summit of Otake collapsed forming a large debris avalanche and creating the horseshoe-shaped Sakuchi caldera, which extends to the eastern coast. The island remained uninhabited for about 70 years after the 1813-1814 eruption. Lava flows reached the eastern coast of the island in 1884. Only about 50 people live on the island.

Information Contacts: JMA, Tokyo.