The upper flanks of the symmetrical Mayon are exceptionally steep, averaging 35-40 degrees. They are covered with solidified lava agglutinate, the molten ejecta of lava fountains. This 1984 photo from the WSW shows a 250-m-deep, 3-km-long gully in the shadow at the right that was eroded by pyroclastic flows during the 1984 eruption.

Photo by Chris Newhall, 1984 (U.S. Geological Survey).

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

Mayon