Tolbachik

SUMMARY:

Type: shield with caldera
Activity: active
Last Eruption: 1976 AD
Rock Type: basaltic
Eruptive Volume: ? cu km
Location Map from Xerox PARC
Latitude: 55.83 N
Longitude: 160.33 E

GEOLOGIC HISTORY

The massive Tolbachik basaltic shield volcano is located at the south end of the dominantly andesitic Kliuchevskaya volcano group, 35 km south of Kliuchevskoi. The Tolbachik massif is composed of two overlapping, but morphologically distinct volcanoes.

The flat-topped Plosky Tolbachik shield volcano contains nested, Holocene, Hawaiian-type calderas and lies east of the older and higher sharp-topped Ostry Tolbachik stratovolcano. Lengthy rift zones extending NE and S of the volcano have erupted voluminous basaltic lava flows during the Holocene, with activity during the past 2,000 years confined to the narrow axial zone of the rifts.

Historic Activity: Tolbachik has erupted 30 times since 1740, most recently in 1975-76 from the summit and S-flank fissures; it was the largest historical basaltic eruption in Kamchatka

Recent Activity:

• Seismic monitoring of Tolbachik began in late January 1994 when two stations were installed. Since then seismicity has been at background levels.

Data Sources

• Smithsonian SEAN Bulletin (V.1, No. 7 and 8)
• Global Volcanism Network (V. 19, No. 1 and V. 24, No. 2).

ADDITIONAL INFORMATION

• Link to Global Volcanism Network's Tolbachik Information
• Link to VolcanoWorld's Tolbachik Info

Last Update: 2/21/00