Report on Kuchinoerabujima (Japan) — November 2010
Bulletin of the Global Volcanism Network, vol. 35, no. 11 (November 2010)
Managing Editor: Richard Wunderman.
Edited by Edward A. Venzke.
Kuchinoerabujima (Japan) Some periods of increased seismicity through 2009; white plumes
Please cite this report as:
Global Volcanism Program, 2010. Report on Kuchinoerabujima (Japan) (Venzke, E.A., and Wunderman, R., eds.). Bulletin of the Global Volcanism Network, 35:11. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN201011-282050
Kuchinoerabujima
Japan
30.443°N, 130.217°E; summit elev. 657 m
All times are local (unless otherwise noted)
No eruptive activity has been reported at Kuchinoerabu-jima since a small eruption in September 1980 (SEAN 05:12). However, there have been many periods of elevated seismicity.
One such episode, beginning in early September 2008, prompted two increases in the hazard status by late October when the seismicity was accompanied by inflation and increased fumarolic activity near the summit (BGVN 33:09). The Alert Level remained at 3 (on a scale of 1-5) until 18 March 2009, when it was decreased to level 2. Sulfur dioxide emissions had decreased in January 2009, followed by a decrease in the rate of deformation.
Seismicity data during 2003-2009. Seismic data recorded by JMA between January 2003 and December 2006 indicted that the number of monthly volcanic earthquakes was typically below 200, with less than 30 tremor events. Seismicity was higher in March 2004, January-February, May, July-September, and November 2005, March-April, August, and October-December 2006, and February and April 2007 (table 1).
Table 1. Months with anomalous seismicity at Kuchinoerabu-jima between January 2003 and December 2009, showing numbers of earthquakes, tremors, and plume observations. Months with either more than 200 volcanic earthquakes or more than 30 tremors are shown, and months with earthquake swarms on specific days. All observed plumes throughout this period were white. Data courtesy of JMA.
| Month | Earthquakes | Tremors | Days with plumes | Plume height (m) | Notes |
| Mar 2004 | 315 | 48 | -- | -- | -- |
| Jan 2005 | 346 | 59 | -- | -- | -- |
| Feb 2005 | 234 | 36 | 4 | 40 | -- |
| May 2005 | 100 | 35 | -- | -- | -- |
| Jul 2005 | 136 | 58 | -- | -- | -- |
| Aug 2005 | 228 | 40 | -- | -- | -- |
| Sep 2005 | 201 | 10 | -- | -- | -- |
| Nov 2005 | 205 | 7 | -- | -- | -- |
| Mar 2006 | 292 | 7 | -- | -- | -- |
| Apr 2006 | 289 | 11 | -- | -- | -- |
| Aug 2006 | 221 | 2 | -- | -- | -- |
| Oct 2006 | 291 | 31 | 1 | 10 | -- |
| Nov 2006 | 479 | 100 | 5 | 30 | -- |
| Dec 2006 | 201 | 32 | 5 | 10 | -- |
| Feb 2007 | 174 | 65 | 2 | 10 | -- |
| Apr 2007 | 127 | 57 | 2 | 10 | -- |
| Sep 2008 | 186 | 49 | 1 | 30 | 70 earthquakes on 4 Sep |
| Oct 2008 | 133 | 94 | 20 | 200 | -- |
| Nov 2008 | 106 | 54 | 25 | 200 | -- |
| Dec 2008 | 138 | 39 | 27 | 200 | -- |
| Apr 2009 | 124 | 67 | 12 | 400 | -- |
| May 2009 | 153 | 96 | 22 | 300 | -- |
| Sep 2009 | 177 | 6 | 10 | 200 | Earthquakes: 75 on 27 Sep, ~750 on 28-29 Sep. Tremors on 28 and 30 Sep. |
| Oct 2009 | 131 | 32 | 10 | 200 | All tremors during 1-6 Oct. |
A seismic swarm consisting of 70 events on 4 September 2008 resulted in the Alert Level increase already reported. The months of September-December 2008 included high numbers of tremor episodes (table 1). Large numbers of tremors were recorded again in April-May 2009. Seismicity decreased after that time, until an earthquake swarm was recorded during 27-29 September 2009 (about 150 earthquakes). Tremor events also increased briefly, with 38 between 28 September and 6 October 2009. White fumarolic plumes rising from the summit area increased in height (up to 400 m) and frequency (every 1-2 days) after September 2008 through 2009.
Geological Summary. A group of young stratovolcanoes forms the eastern end of the irregularly shaped island of Kuchinoerabujima in the northern Ryukyu Islands, 15 km W of Yakushima. The Furudake, Shindake, and Noikeyama cones were erupted from south to north, respectively, forming a composite cone with multiple craters. All historical eruptions have occurred from Shindake, although a lava flow from the S flank of Furudake that reached the coast has a very fresh morphology. Frequent explosive eruptions have taken place from Shindake since 1840; the largest of these was in December 1933. Several villages on the 4 x 12 km island are located within a few kilometers of the active crater and have suffered damage from eruptions.
Information Contacts: Japan Meteorological Agency (JMA), Otemachi, 1-3-4, Chiyoda-ku Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/)
