Sarychev volcano is one of the most active volcanoes in the Kuril Island chain streching between Kamchatka and Japan. Large explosive eruptions occured between 11-19 June 2009, sending huge ash coulds to altitudes of up to 14 km, and forcing many flights with routes accross the northern Pacific to be cancelled or diverted.

Sarychev Peak, one of the most active volcanoes of the Kuril Islands, occupies the NW end of Matua Island in the central Kuriles. The andesitic central cone was constructed within a 3-3.5 km wide caldera, whose rim is exposed only on the SW side. A dramatic 250-m-wide, very steep-walled crater with a jagged rim caps the volcano. The substantially higher SE rim forms the 1496 m high point of the island. Fresh-looking lava flows descend all sides of Sarychev Peak and often form capes along the coast. Much of the lower-angle outer flanks of the volcano are overlain by pyroclastic-flow deposits. Eruptions have been recorded since the 1760's and include both quiet lava effusion and violent explosions.

The largest historical eruption of Sarychev Peak began on June, 11, 2009 and produced ash plumes rising to up to 14 kms and pyroclastic flows that reached the sea. The ash plumes drifting westwards at altitudes typical for commercial airplanes forced many flights with routes accross the northern Pacific to be cancelled or diverted.