The substantially higher SE rim of the Sarychev 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. Sarychev Peak eruptions have been recorded since the 1760's and include both quiet lava effusion and violent explosions. One of the largest historical eruptions of Sarychev Peak in 1946 produced pyroclastic flows that reached the sea.
On 12 June 2009, the Sarychev volcano erupted again, spewing out ash plumes high into the sky. As the volcano is near some of the main air routes between East Asia and North America, there was some disruption to air traffic. During the eruption, the International Space Station passed overhead and astronauts were able to photograph the event. A hole in the overhead clouds, possibly caused by the shock wave from the explosion, allowed a clear view of the plume and pyroclastic flow down the sides of the mountain. A cap-like pileus cloud is visible atop the rising column. Sarychev Peak had previously erupted in 1760, 1805, 1879, 1923, 1927, 1928, 1930, 1932, 1946, 1954, 1960, 1965, 1976, 1986 and 1989.
Sarychev Volcano Eruption Seen From The International Space Station