The Univ of Colima (37 km S of the volcano) reported that a sulfur smell and increased fumarolic activity were noticeable on 2 March and twice during the next few weeks. A seismic station near the university detected a few small A-type earthquakes/day. The Instituto de Geofísica is installing a portable seismic station at the base of the volcano. A sulfur smell had not been reported for at least 10 years.

Geological Summary. The Colima complex is the most prominent volcanic center of the western Mexican Volcanic Belt. It consists of two southward-younging volcanoes, Nevado de Colima (the high point of the complex) on the north and the historically active Volcán de Colima at the south. A group of late-Pleistocene cinder cones is located on the floor of the Colima graben west and east of the complex. Volcán de Colima (also known as Volcán Fuego) is a youthful stratovolcano constructed within a 5-km-wide scarp, breached to the south, that has been the source of large debris avalanches. Major slope failures have occurred repeatedly from both the Nevado and Colima cones, producing thick debris-avalanche deposits on three sides of the complex. Frequent recorded eruptions date back to the 16th century. Occasional major explosive eruptions have destroyed the summit (most recently in 1913) and left a deep, steep-sided crater that was slowly refilled and then overtopped by lava dome growth.

Information Contacts: S. de la Cruz-Reyna, UNAM.