Photo Information

River valley filled with pyroclastic-flow deposits
Photograph by W.E. Scott on July 1, 1991.
Pyroclastic flows erupted by Mount Pinatubo on June 15, 1991, buried the Marella River valley (SW of Pinatubo) with pumice, ash, and other volcanic rocks to depths of between 50 and 200 m. This eruption was one of the largest in the 20th century, depositing about 5.5 km3 of rock debris over nearly 400 km2. The pyroclastic flows traveled as far as 12 to 16 km from the volcano in all directions. Unlike river valleys, the steep slopes around the volcano were veneered with very thin, discontinuous pyroclastic-flow deposits.

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U.S. Department of the Interior, U.S. Geological Survey, Menlo Park, California, USA
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Last modification: 16 December 1999 (SRB)