Kiska Volcano | John Seach


Aleutian Islands, Alaska

52.10 N, 177.60 W
summit elevation 1220 m

Kiska volcano is located in the Rat Island group, Aleutian Islands, Alaska. Kiska is the westernmost island in the Rat group. The island was sighted by Bering during a voyage in 1741, when it was occupied by an Aleut population.

Kiska contains one of the best harbours in the Aleutian Islands. The coastline of Kiska volcano is continuous cliff that ranges in height from tens of metres to over 500 m.

Kiska is a young composite andesite volcano, occupying the northern part of the island. The southern side of the island is an extension of a submarine ridge.

Kiska volcano and harbour contain interbedded andesitic to basaltic pyroclastic rocks, lava flows, and sedimentary rocks formed from volcanic debris. The eastern side of the island was modified by glaciers. A thin layer of volcanic ash on the island has been erupted from nearby volcanoes.

Kiska Edifice Failure
A region of hummocky seafloor terrain extends 30 km NNW of Kiska volcano. This indicates a previous edifice failure at the volcano, even though no subaerial evidence exists.

1990 Eruption
Ash emissions were observed at Kiska volcano on 1st June 1990. Emission came from an upper flank vent.

1987 Eruption
An eruption plume extending 60 km east of Kiska volcano was detected on satellite images on 15th April 1987.

1969 Eruption
On 11th September 1969 an eruption was observed, with ash to 400 m high and steam to 4000 m.

1962 Eruption
An eruption in 1962 formed a 30 m high cinder cone.

Possible eruption in 1943
Newspaper reports in June 1943, shortly before the island was occupied by American and Canadian forces, describe an ash eruption accompanied by earthquakes. When the mountain was climbed in 1947, there was no evidence of recent ash emission, and no solfataric or fumarolic activity.

1905 Solfatara
Active solfatara were observed in the crater in 1905.

Kiska Volcano Eruptions

1990, 1987, 1969, 1964, 1962, 1927?, 1907?