The Ninahuilca lava domes, which form the twin forested peaks below the right-center horizon, were created during an eruption about 2400 years ago. Growth of the lava domes within the summit caldera of Atacazo volcano was accompanied by plinian explosive eruptions and pyroclastic flows that traveled 35 km down valleys to the west.

Photo by John Ewert, 1992 (U.S. Geological Survey).

This image is made available as a Public Domain Work, but proper attribution is appreciated.

Atacazo