Zoa

SUMMARY:

Type: composite
Activity: dormant
Last Eruption: 1940 AD
Rock Type: ?
Eruptive Volume: ? cu km
Location Map from Xerox PARC
Latitude: 38.15 N
Longitude: 140.45 E

GEOLOGIC HISTORY

The Zao volcano group, the most active of northern Honshu, consists of a complex cluster of stratovolcanoes straddling the Pacific Ocean-Japan Sea divide. The Pleistocene Ryu-zan and Aoso volcanoes form the northern and southern Zao groups, respectively, NW and SE of the central Zao group. Zao volcano proper forms the central Zao group, a volcanic complex topped by several lava domes and the Goshiki-dake tuff cone. Goshiki-dake contains the active Okama crater, filled with a colorful crater lake. It has been the source of most of the frequent historical eruptions of Zao volcano.

Historic Activity: More than 30 eruptions from the Zoa complex have been documented in the past 1200 years, the most recent an emission of fine sulfur in 1939-40.

Recent Activity: A seismic shock of M 4.7 occurred on Sept. 1, 1992 a few kilometers ESE of the summit.

Data Sources

• Global Volcanism Network (V. 17, No. 9).

ADDITIONAL INFORMATION

• Link to Global Volcanism Network's Zoa Information

Last Update: 2/27/00