Oshima-Oshima
About Oshima-Oshima
Oshima-Oshima, a 10 km2 island about 105 km W offshore from the SW tip of Hokkaido, is the emergent summit of two coalescing basaltic-to-andesitic stratovolcanoes. Higashiyama, at the east end of the island, is cut by a 2-km-wide caldera covered on its west side by Nishiyama volcano. The western cone failed during an eruption in 1741 CE, producing a mostly submarine debris avalanche that traveled 16 km and leaving a scarp open to the north. A tsunami associated with the collapse swept the coasts of Hokkaido, western Honshu, and Korea, and caused nearly 1,500 fatalities. The 1741 eruption concluded with the construction of a basaltic pyroclastic cone at the head of the amphitheater. No eruptions have occurred since the late-18th century.
Eruption reports
Reports from GDACS and NASA EONET linked to this volcano.
No eruption reports in our records yet. New reports appear here automatically.
Earthquakes nearby, 30 days
Within about 50 km. Swarms of small quakes can sometimes accompany volcanic unrest.
No earthquakes recorded nearby in the last 30 days.