Galeras is one of Colombia's most frequently active volcanoes. The dominantly andesitic volcano has been active for more than 1 million years, and two major caldera collapse eruptions took place during the past 100,000 years. Several collapse events have produced 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 in the past thousands of years 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.
Uploaded: Aug 21, 2015