Report on Suwanosejima (Japan) — July 2005
Bulletin of the Global Volcanism Network, vol. 30, no. 7 (July 2005)
Managing Editor: Edward Venzke.
Suwanosejima (Japan) Eruptions during April 2004-July 2005 send plumes to varying heights
Please cite this report as:
Global Volcanism Program, 2005. Report on Suwanosejima (Japan) (Venzke, E., ed.). Bulletin of the Global Volcanism Network, 30:7. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200507-282030
Suwanosejima
Japan
29.638°N, 129.714°E; summit elev. 796 m
All times are local (unless otherwise noted)
Several small eruptions during December 2003 and January 2004 at Suwanose-jima produced ash plumes to unknown heights (BGVN 29:03). Little activity was observed during the first four months of 2004. From the end of April 2004 to the end of July 2005, numerous eruptions and explosions produced plumes reported by the Tokyo Volcanic Ash Advisory Center (VAAC), including some observed by pilots (table 3).
Table 3. Summary of activity at Suwanose-jima from April 2004 to July 2005 based on information from the Tokyo VAAC. "--" indicates data not reported or unknown.
| Date | Time Period | Plume Altitude (km) | Drift Direction | Activity |
| 28 Apr 2004 | -- | 3 | SE | Ash emission |
| 01 May 2004 | 0906 | -- | -- | Explosion |
| 07 Jun 2004 | -- | 2 | E | Gas plume |
| 08 Jun 2004 | -- | 2 | E | Gas and ash |
| 09 Jun 2004 | 1003 | 1.8 | E | Ash plume |
| 09 Jun 2004 | 1300 | -- | -- | Ash plume |
| 30 Jun-05 Jul 2004 | various | max 1.9 | -- | Several explosions |
| 30 Nov 2004 | 1607 | 1.2 | -- | Eruption |
| 20 Dec 2004 | -- | 1.8 | SE | Eruption |
| 21 Dec 2004 | -- | -- | SE | Eruption |
| 22 Dec 2004 | -- | -- | -- | Ash plume |
| 24 Dec 2004 | -- | -- | -- | Ash plume |
| 25 Dec 2004 | -- | -- | -- | Ash plume |
| 27 Dec 2004 | -- | -- | -- | Ash plume |
| 29 Dec 2004 | -- | 1.2 | -- | Ash plume |
| 01 Jan 2005 | -- | -- | -- | Eruption |
| 04 Jan 2005 | -- | -- | -- | Eruption |
| 06 Mar 2005 | -- | 1.5 | -- | Ash emission |
| 08 Mar 2005 | -- | 1.2 | -- | Ash emission |
| 09 Mar 2005 | -- | 1.8 | -- | Ash plume |
| 26 Apr 2005 | -- | 1.2 | E | Eruption |
| 26 May-31 May 2005 | various | max 2.1 | -- | Several ash explosions |
| 01 Jun-06 Jun 2005 | various | Several ash explosions | 1.8 | -- |
| 06 Jul 2005 | various | -- | -- | Several ash explosions |
| 27 Jul 2005 | -- | 0.8 | -- | Eruption with ash |
| 28 Jul 2005 | -- | 2.4 | -- | Ash plume |
Geological Summary. The 8-km-long island of Suwanosejima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two active summit craters. The summit is truncated by a large breached crater extending to the sea on the E flank that was formed by edifice collapse. One of Japan's most frequently active volcanoes, it was in a state of intermittent Strombolian activity from Otake, the NE summit crater, between 1949 and 1996, after which periods of inactivity lengthened. The largest recorded eruption took place in 1813-14, when thick scoria deposits covered 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 an open collapse scarp extending 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: Tokyo Volcanic Ash Advisory Center, Japan Meteorological Agency (JMA), 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan (URL: https://ds.data.jma.go.jp/svd/vaac/data/).
