Symmetrical, glacier-clad Cotopaxi stratovolcano is Ecuador's most well-known volcano and one of its most active. The steep-sided cone is capped by nested summit craters, the largest of which is about 550 x 800 m in diameter. Deep valleys scoured by lahars radiate from the summit of the andesitic volcano, and large andesitic lava flows extend to its base. The modern conical edifice has been constructed since a major collapse sometime prior to about 5000 years ago. Pyroclastic flows (often confused in historical accounts with lava flows) have accompanied many explosive eruptions, and lahars have frequently devastated adjacent valleys. The most violent historical eruptions took place in 1744, 1768, and 1877. Pyroclastic flows descended all sides of the volcano in 1877, and lahars traveled more than 100 km into the Pacific Ocean and western Amazon basin. The last significant eruption took place in 1904.
Symmetrical Cotopaxi is one of the most prominent volcanoes that line both sides of the Interandean valley along Ecuador's "Avenue of Volcanoes." Cotopaxi, one of Ecuador's most active volcanoes, has produced more than 50 eruptions since the 16th century. Glaciers cover the upper part of the cone from 4700 m altitude on the west flank, seen here, to the 5911-m-high summit. Devastating lahars in historical time swept this valley before turning south and then east into the Amazon basin. Lahars to the NW reached the Pacific Ocean.
Photo by Lee Siebert, 1978 (Smithsonian Institution).
Last updated 2020-01-10 18:30:04