Gareloi Volcano

Southern flank of Mount Gareloi

The Mount Gareloi is a stratovolcano, which forms the main part of the island Gareloi in the Aleutian Islands (Alaska).

Construction

The volcano has at its base a diameter of eight to ten kilometers and a maximum altitude of 1573 meters and has two craters. The coated from fumaroles southern crater is larger and measures about 300 meters in diameter, due to the partially slid down south wall. In the south wall there is a crack that originated during the eruption in 1929 and runs to the coast. The northern crater is covered by lava flows. At its northwestern flank evidently a Domeinsturz has occurred. The Alaska Volcano Observatory has mapped the volcano and its surroundings in 2003. In addition, seismographs were installed.

Eruption history

Since the discovery of the island in 1741 about twelve outbreaks were registered, which were accompanied by lava flows and pyroclastic flows. As a rule, first was an outbreak of the main chimney, followed by an explosive gas and ash eruption, partially covered by a phreatic explosion. The outbreaks were classified with a Vulkanexplosivitätsindex 1-3. Such outbreaks were in 1790, 1791, 1792, 1873, 1922, held in April 1929, 1950, January 17, 1952 August 7, 1980 on 15 January 1982, and on September 4, 1987 and August 17, 1989 instead. Further eruptions in the years 1760, 1828, 1927 and 1996 are not backed up.

The outbreak in 1929 was the most severe in the young history of research on the volcano. Four lava flows re-emerged. In the southern flank of the mountain a large crack with 13 small craters originated. The deposits after the eruption was accompanied by pyroclastic flows and lahar streams.