Report on Koryaksky (Russia) — 25 March-31 March 2009
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 25 March-31 March 2009
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2009. Report on Koryaksky (Russia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 25 March-31 March 2009. Smithsonian Institution and US Geological Survey.
53.321°N, 158.712°E; summit elev. 3430 m
All times are local (unless otherwise noted)
KVERT reported that seismic activity at Koryaksky was at background levels during 20-27 March. Gas plumes containing a small amount of ash rose to an altitude of 4 km (13,200 ft) a.s.l. and drifted S, SE, W and NW during the reporting period. On 25 and 26 March, gas-and-ash plumes were also seen on satellite imagery and drifted 225 km SE. The Level of Concern Color Code remained Orange.
Based on information from the Yelizovo Airport and KEMSD, and analysis of satellite imagery, the Tokyo VAAC reported that during 26-27 and 29 March ash plumes rose to altitudes of 3-3.7 km (10,000-12,000 ft) a.s.l. and drifted S, SW, and W.
Geologic Background. 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.