Report on Kolokol Group (Russia) — April 1987
Scientific Event Alert Network Bulletin, vol. 12, no. 4 (April 1987)
Managing Editor: Lindsay McClelland.
Kolokol Group (Russia) Weak gas emission from the Berg and Trezubetz domes
Please cite this report as:
Global Volcanism Program, 1987. Report on Kolokol Group (Russia) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 12:4. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198704-290120.
46.042°N, 150.083°E; summit elev. 1328 m
All times are local (unless otherwise noted)
Weak gas emission from the extrusive domes at Berg and Trezubetz was noted during a 6 November overflight. Five explosive eruptions and one dome-building episode are known between 1845 and 1970.
Geologic Background. A group of Holocene volcanoes in central Urup Island is named after its most prominent volcano, Kolokol. Berg and Trezubetz volcanoes, flanking Kolokol on the NW, have breached summit calderas partially filled by lava domes. Trezubetz, whose name means "Trident," has an eroded crater rim with three large peaks when seen at sea from the north. Kolokol rises to 1328 m and is sometimes known as Urup-Fuji because of its symmetrical profile. The crater of Kolokol is not well preserved, but there is no evidence of glacial erosion. Several lava flows originate from Kolokol; one of these extends almost to the Sea of Okhotsk coast; a viscous lava flow armoring the SE flank is probably the most recent. Borzov volcano, the oldest of the group, lies to the SW of Kolokol. Eruptions of the Kolokol group have been observed in historical time since the late-18th century. Berg volcano has been most active, but Trezubetz erupted in 1924.
Information Contacts: G. Steinberg and B. Piskunov, Yuzhno-Sakhalinsk.