El Chichón is a volcano in the southeastern Mexican state of Chiapas. Its caldera (crater) is about 980 feet (300 meters) deep and about 3,280 feet (1 kilometer) across. Its highest rim rises to an elevation of 3,772 feet (1,150 meters). The volcano sits at the northern end of the Chiapanecan Volcanic Arc, one of several chains of volcanic mountains in Central America. The area is part of the Ring of Fire, a turbulent zone of frequent seismic and volcanic activity along the islands and continents rimming the Pacific Ocean. El Chichón means the bump in English.
El Chichón is a rounded lava dome volcano built up of many lava flows issued from a central vent. The volcano’s last major eruption was in 1982, when pyroclastic flows (super-heated masses of gas and volcanic material) devastated the area and killed about 2,000 people. That eruption formed the volcano’s current caldera, which contains a blue-green acidic lake. The water’s color comes from dissolved minerals and large amounts of ashy sediment. Hot springs and fumaroles (volcanic vents) in the caldera cause parts of the lake to boil.
