Centro Universitario de Estudios e Investigaciones de Vulcanologia - Universidad de Colima reported increased seismicity at Colima during 20-26 April characterized by a considerable increase in the number of high-frequency and volcano-tectonic events. On 26 April a consensus was reached to raise the Alert Level to Yellow (the second lowest level on a four-color scale) and extend the exclusion zone to a 8-km radius during a meeting of the Coordinación Nacional de Protección Civil (CNPC), the Unidad Estatal de Protección Civil Colima (UEPC), the Unidad Estatal de Protección Civil y Bomberos de Jalisco (UEPCBJ), the Universidad de Colima (UdeC), and la Universidad de Guadalajara (UdeG). Seismicity continued to be elevated through 3 May. The largest events (M 2.4-3) were located 0.5-3 km deep in the N and NE parts of the volcano.

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.

Source: Centro Universitario de Estudios Vulcanológicos (CUEV) - Universidad de Colima