Report on Niijima (Japan) — July 1996
Bulletin of the Global Volcanism Network, vol. 21, no. 7 (July 1996)
Managing Editor: Richard Wunderman.
Niijima (Japan) Seismic activity increases
Please cite this report as:
Global Volcanism Program, 1996. Report on Niijima (Japan) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 21:7. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199607-284020
Niijima
Japan
34.397°N, 139.27°E; summit elev. 432 m
All times are local (unless otherwise noted)
High seismicity around the island was recorded on 17 and 24-26 July. The largest earthquakes (M 4.0) were detected at 1250 and 1321 on 17 July.
Geological Summary. The elongated island of Niijima, SSW of Oshima, is 11 km long and only 2.5 km wide. Eight low rhyolitic lava domes are clustered in two groups at the northern and southern ends of the island, separated by an area of flat-topped domes and a low isthmus of pyroclastic deposits. The Mukaiyama complex on the south and the Atchiyama lava dome on the north were formed during eruptions in the 9th century CE, the last known activity. Shikineyama and Zinaito domes form small islands immediately to the SW and W, respectively, during earlier stages of volcanism. Earthquake swarms occurred during the 20th century.
Information Contacts: Volcanological Division, Japan Meteorological Agency, 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan
