Report on Niijima (Japan) — August 1992
Bulletin of the Global Volcanism Network, vol. 17, no. 8 (August 1992)
Managing Editor: Lindsay McClelland.
Niijima (Japan) Weak earthquake swarm
Please cite this report as:
Global Volcanism Program, 1992. Report on Niijima (Japan) (McClelland, L., ed.). Bulletin of the Global Volcanism Network, 17:8. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199208-284020
Niijima
Japan
34.397°N, 139.27°E; summit elev. 432 m
All times are local (unless otherwise noted)
A weak earthquake swarm was detected in the sea a few kilometers E and W of the island on 28-29 August. The strongest event was M 2.3.
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: JMA.
