The flat, lighter-green, vegetated deposit that winds down the valley at the top center of the photo is a pyroclastic flow fan from the last major eruption of Pinatubo prior to 1991, about 500 years ago. This photo, taken on 3 June 1991, shows the pre-eruption profile of the upper Marella River valley.

Photo by Rick Hoblitt, 1991 (U.S. Geological Survey).

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

Pinatubo