June 12, 1991, Eruption Cloud of
Mt. Pinatubo from Clark Air Base

Slide Set: THE JUNE 1991 ERUPTION OF MOUNT PINATUBO, PHILIPPINES Slide Number: 73900705 ERUPTION PHASES. View to the west from Clark Air Base of the first major eruption of Pinatubo on June 12, 1991. After more than two months of increasing seismicity, localized deformation, and emission of small plumes, a series of strong explosions and a tephra column on this date heralded the start of the major pyroclastic phase. The tephra column rose to about twenty km. Photograph Credit: R.S. Culbreth, U.S. Air Force.

(Data Source: http://www.ngdc.noaa.gov/cgi-bin/seg/menuscripts/)