Report on Koryaksky (Russia) — 18 March-24 March 2009
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 18 March-24 March 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, 18 March-24 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 elevated on 13 March and at background levels on the other days during 14-20 March. Observers reported that gas plumes containing a small amount of ash rose to an altitude of 4 km (13,200 ft) a.s.l. and drifted in easterly directions during the reporting period. The plumes were also seen on satellite imagery drifting 140 km away from the volcano. Ash was emitted from the upper fumarolic vent and covered the flanks. The Level of Concern Color Code remained 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.