According to the Universidad de Colima, an explosion at Colima on 28 August at 2352 produced an ash plume that rose to a height of ~3 km above the volcano's crater. The explosion was accompanied by pyroclastic flows that traveled 2 km down the S flank and volcanic blocks. Residents of the city of Colima, ~32 km from the volcano, heard the explosion and ash fell in the town of Grullo, ~60 km NW of the volcano. Seismic data revealed that this explosion was similar in size to one on 2 August.

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.

Sources: Centro Universitario de Estudios e Investigaciones de Vulcanologia - Universidad de Colima, Associated Press, Washington Volcanic Ash Advisory Center (VAAC)