Galeras (Colombia)

Status Unrest Eruption 2014 4276m
Complex (Subduction zone / Continental crust (> 25 km))

Galeras

Galeras, a stratovolcano with a large breached caldera located immediately west of the city of Pasto, is one of Colombia's most frequently active volcanoes. The dominantly andesitic complex has been active for more than 1 million years, and two major caldera collapse eruptions took place during the late Pleistocene. Long-term extensive hydrothermal alteration has contributed to large-scale edifice collapse on at least three occasions, producing debris avalanches that swept to the west and left a large horseshoe-shaped caldera inside which the modern cone has been constructed. Major explosive eruptions since the mid-Holocene have produced widespread tephra deposits and pyroclastic flows that swept all but the southern flanks. A central cone slightly lower than the caldera rim has been the site of numerous small-to-moderate historical eruptions since the time of the Spanish conquistadors.

Galeras, a stratovolcano with a large breached caldera located immediately west of the city of Pasto, is one of Colombia's most frequently active volcanoes. It is seen here from the south on March 17, 1989, with steam clouds pouring from vents on the large central cone near the back headwall of the caldera, whose south rim forms the ridge in the foreground. Major explosive eruptions since the mid Holocene have produced widespread tephra deposits and pyroclastic flows that swept all but the southern flanks.

Photo by Norm Banks, 1989 (U.S. Geological Survey).

Last updated 2019-10-11 11:00:03

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