Global Volcanism Program | Image GVP-01927
Thick pyroclastic flow deposits from the 1991 eruption of Pinatubo were rapidly eroded in the years following the eruption. This 7 September 1994 view of the upper Marella River valley from the SW, with the caldera rim on the skyline, shows the effects of the erosion of well over 100 m of pyroclastic flow deposits. The closest forest-covered hill (left center) was entirely surrounded by 15 June 1991 pyroclastic flow deposits. Light-colored deposits in the channels at the middle right and lower left are post-1991 lahar deposits.
Photo by Chris Newhall, 1994 (U.S. Geological Survey).