We are currently having technical problems with the volcano profiles, Weekly Reports, and Current Eruptions pages, but expect to have them restored on 24 May. Sorry for the inconvenience.
Logo link to homepage

Report on Koryaksky (Russia) — 19 August-25 August 2009


Koryaksky

Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 19 August-25 August 2009
Managing Editor: Sally Sennert.

Please cite this report as:

Global Volcanism Program, 2009. Report on Koryaksky (Russia) (Sennert, S, ed.). Weekly Volcanic Activity Report, 19 August-25 August 2009. Smithsonian Institution and US Geological Survey.

Weekly Report (19 August-25 August 2009)

Koryaksky

Russia

53.321°N, 158.712°E; summit elev. 3430 m

All times are local (unless otherwise noted)


KVERT reported that during 14-21 August seismic activity from Koryaksky was slightly above background levels. During 13-16 August, gas-and-steam plumes rose to altitudes of 3.5-5 km (11,500-16,400 ft) a.s.l. Based on visual observations during 16-20 August, gas-and-steam plumes containing ash rose to altitudes of 3.5-4.2 km (11,500-13,800 ft) a.s.l. and drifted in multiple directions. Ash plumes were also seen in satellite imagery, drifting 215 km E and W. On 23 August, a probable ash plume detected in satellite imagery drifted 50 km ESE. During 24-25 August, seismicity increased; more than 100 earthquakes were recorded. The Level of Concern Color Code remained at Orange.

Geological Summary. The large symmetrical Koryaksky stratovolcano is the most prominent landmark of the NW-trending Avachinskaya volcano group, which towers above Kamchatka's largest city, Petropavlovsk. Erosion has produced a ribbed surface on the eastern flanks of the 3430-m-high volcano; the youngest lava flows are found on the upper W flank and below SE-flank cinder cones. Extensive Holocene lava fields on the western flank were primarily fed by summit vents; those on the SW flank originated from flank vents. Lahars associated with a period of lava effusion from south- and SW-flank fissure vents about 3900-3500 years ago reached Avacha Bay. Only a few moderate explosive eruptions have occurred during historical time, but no strong explosive eruptions have been documented during the Holocene. Koryaksky's first historical eruption, in 1895, also produced a lava flow.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)