Aleutian Islands, Alaska
51.78 N, 178.80 W
summit elevation 1573 m
Gareloi Volcano is located in the western Aleutian Islands, Alaska. It is about 2,000 kilometers west-southwest of Anchorage and about 150 kilometers west of Adak.
The volcano has two summits - North Peak and South Peak, separated by 500 m, and both possess volcanic craters. A glacier is located in the saddle between the two peaks. North Peak is the volcano’s summit, and contains a 300×350m, 100 m deep crater. South Peak contains a 300 m wide crater which forms an amphitheater created during a collapse during the 1929 eruption. The South Peak crater contains several active fumaroles.
Two large earthquakes (magnitude 6.6 and 6.4) and a swarm of smaller ones occurred near the volcano on 15th April 2008.
On 27th September 1996, a pilot reported a minor eruption of ash and steam from the volcano to 5,000 ft altitude.
On 17th August 1989 a gray-black ash plume was observed rising about 2,300 ft above North Peak crater.
A debris or lava flow occurred on 4th September 1987. The flow extended from North Peak crater rim at 1,500 m altitude down to at least 1,100 m. Steam rose 100 m above the flow.
On 14th January 1982, a magnitude 3.3 earthquake was recorded near Gareloi Volcano. The following day an explosive eruption sent ash to 30,000 ft altitude.
On 8th August 1980 an ash plume was observed rising to an altitude of 40,000 ft.
South Peak Effusive Eruption (Between 1946 and 1980)
Minor ash and gas emissions were observed at Gareloi volcano in 1950 and 1952. A lava flow extends 800 m SE from South Peak crater, and erupted sometime between 1946 and 1980.
The largest historical eruption at Gareloi volcano occurred in 1929. A fissure eruption formed 13 craters, including South Peak Crater. An explosive eruption deposited several metres of tephra over the southern half of the island. During the second half of the eruption, craters and associated lava flows formed lower on the flank of the volcano.
1996, 1989, 1987, 1982, 1980, 1952, 1950, 1929-30, 1027?, 1922, 1873,
?1828-29, 1792, 1791, 1790, 1760?