Oshima-Oshima

Japan - Hokkaido

SUMMARY:

Type: composite
Activity: dormant
Last Eruption: 1790 AD
Rock Type: ?
Eruptive Volume: ? cu km
Location Map from Xerox PARC
Latitude: 41.50 N
Longitude: 139.37 E

GEOLOGIC HISTORY

This small island 55 km west of Hokkaido in the Japan Sea consists of two coalescing volcanoes.

Historic Activity: An eruption in August 1741 produced heavy ashfall on the Hokkaido mainland. A violent explosion and landsliding from the Nishi-yama cone accompanied a large tectonic earthquake and a major tsunami that killed 1,475 people, most on the west coast of the Oshima Peninsula. Subsequent eruptions through early 1742 produced a new central cone and lava flows. Minor explosive activity was documented in 1759, 1786, and 1790.

Recent Activity: Volcanic earthquakes and tremors were detected near the end of March 1996 by instruments maintained by Hokkaido University.

Data Sources

  • Global Volcanism Network (V. 21, No. 3).

ADDITIONAL INFORMATION

Last Update: 2/26/00