Ceboruco

Volcán Ceboruco is the only volcano in the NW part of the Mexican Volcanic Belt with observed eruptions. The complex stratovolcano rises above the floor of the Tepic graben and is truncated by two concentric summit calderas. Eruption of the voluminous rhyodacitic Jala Pumice formed the initial 4-km-wide caldera about 1,000 years ago. The second caldera, 1.5 km wide, was formed by collapse of part of the large Dos Equis dacitic lava dome, which partly filled the earlier caldera. About 15 basaltic and andesitic cinder cones and lava flows have erupted along a NW-SE-trending line cutting across Ceboruco. The massive, sparsely vegetated El Norte lava flow, probably erupted in the past few hundred years, covers the entire N flank. The last eruption took place during 1870-1875 CE. Explosive eruptions from a vent on the upper W flank accompanied extrusion of a 1.1 km3 dacitic lava flow that covers a large area on the lower W flank.