Mt. Pinatubo Anniversary and Lahar Danger
June 15, 2001
Mount Pinatubo is located on the Island of Luzon in the Philippines, about 100 km northwest of Manila. On April 2, 1991, Pinatubo, which had been rumbling for months, stirred to life. Over the next six weeks earth tremors and minor explosions occurred. These natural warnings led to the evacuation of personnel at Clark Air Base and of 55,000 people in nearby towns and villages. At dawn on June 15, 1991, a cataclysmic eruption began with a tremendous explosion that destroyed ten deserted villages. The eruption deposited approximately 5 to 7 sq km of volcanic fragments in pyroclastic flows on the slopes of the volcano and over neighboring towns and agricultural areas. It is this material that continues to threaten structures and lives in the area, in the form of lahars (debris flows) during heavy rainstorms. This photo shows older (at least 400 years old) and recent (1991) pyroclastic flow deposits from Mt. Pinatubo.