The stratovolcano is in the Pacific Ring of Fire, an area of the earth's crust where the land is unstable. It encircles the Pacific Ocean, and houses some of the world's most active volcanoes. The volcano is the northernmost of several Colombian stratovolcanoes in the Andean Volcanic Belt of western South America. The Andean volcanic belt was produced by the eastward subduction of the oceanic Nazca plate beneath the South American continental plate. Normally, these type of stratovolcanoes generate explosive Plinian eruptions with associated pyroclastic flows that can melt snow and glaciers near the summit, thus producing devastating lahars.