The Río Naolinco lava flow, which fills the entire valley floor in the foreground, is the most voluminous of two chemically distinct lava flows erupted from El Volcancillo on the south flank of Cofre de Perote volcano about 900 years ago. The Río Naolinco flow traveled 50 km and has an estimated volume of about 1.3 km³. This view looks south across the flow near its widest point about 25 km from the vent.

Photo by Lee Siebert, 2000 (Smithsonian Institution).

This image is made available under the Public Domain Dedication CC0 license, but proper attribution is appreciated.

Cofre de Perote