Report on Niijima (Japan) — March 1993
Bulletin of the Global Volcanism Network, vol. 18, no. 3 (March 1993)
Managing Editor: Edward Venzke.
Niijima (Japan) Earthquake swarm on 23 March; no surface anomalies
Please cite this report as:
Global Volcanism Program, 1993. Report on Niijima (Japan) (Venzke, E., ed.). Bulletin of the Global Volcanism Network, 18:3. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199303-284020
Niijima
Japan
34.397°N, 139.27°E; summit elev. 432 m
All times are local (unless otherwise noted)
A weak earthquake swarm occurred 23 March in the N part of Nii-jima island. The earthquakes, M 1.9 maximum, were located both onshore and offshore. . . . No surface anomalies, onshore or offshore, were observed . . . .
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.
