Available Weekly Reports
26 August-1 September 2009
Based on analyses of satellite imagery, SVERT reported that on 26 August a gas-and-steam plume possibly containing ash rose from Berg (part of the Kolokol Group of volcanoes) to an altitude greater than 6 km (19,700 ft) a.s.l. and drifted NE.
Sources: Sakhalin Volcanic Eruption Response Team (SVERT)
26 August 2009Back to Top
Summary of eruption dates and Volcanic Explosivity Indices (VEI).
|Start Date||Stop Date||Eruption Certainty||VEI||Evidence||Activity Area or Unit|
|[ 2009 Aug 26 ]||[ Unknown ]||Uncertain||2||Berg|
|[ 2005 ]||[ Unknown ]||Uncertain||1||Berg|
|1973 Jul 25||1973 Jul 26 (?)||Confirmed||1||Historical||Berg (northern part of lava dome)|
|1970 Feb||1970 Mar||Confirmed||3||Historical||Berg|
|1952 Jan 15 ± 45 days||Unknown||Confirmed||2||Historical||Berg|
|1946 Apr 15 ± 45 days||Unknown||Confirmed||2||Historical||Berg|
|1940 ± 6 years||Unknown||Confirmed||Historical||Berg|
|1924 Mar 13||Unknown||Confirmed||2||Historical||Trezubetz|
|1894 Jul 25||1894 Jul 26||Confirmed||2||Historical||Berg ?|
|1780 ± 10 years||Unknown||Confirmed||2||Historical|
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 volcano 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 the volcano displays 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 from Kolokol. Borzov volcano, the oldest of the group, lies to the SW of Kolokol. Eruptions of the Kolokol volcano group have been observed in historical time since the late-18th century. Berg volcano has been most active, but Trezubetz erupted in 1924.