Global Volcanism Program | Image GVP-10022
Cerro El Colli is a small rhyolitic lava dome that is one of the youngest post-caldera domes of the Sierra La Primavera volcanic complex, immediately west of the city of Guadalajara. The dome, seen here from the south, has been dated at about 30,000 years and is the easternmost of several emplaced along an arc near the southern caldera margin. An 11-km-wide caldera was formed as a result of the eruption of the 20 cu km Tala Tuff about 95,000 years ago. Steam vents and hot springs currently are active throughout the volcanic complex.
Photo by Hugo Delgado-Granados, (Universidad Nacional Autónoma de México).