Mt Pinatubo Case Study
Mt Pinatubo
Introduction
Where: Mount Pinatubo, Philippines, Asia
When: June 12th-15th, 1991
Type of volcano: Strato or composite volcano
Type of eruption: Explosive - the second biggest eruption this century
Deaths: 300 people died, 1000's were evacuate
Mount Pinatuba had been dormant for 500 years. The first sign that this situation might be changing occured on July 16, 1990 when a magnitude 7.8 earthquake (roughly the size of the 1906 San Francisco earthquake) struck about 60 miles (100 kms.) northeast of Mount Pinatubo on the island of Luzon in the Philippines. This caused the shaking and squeezing of the Earth's crust beneath the volcano. At Mount Pinatubo, scientists recorded a landslide, some local earthquakes, and a short-lived increase in steam emissions from a pre-existing geothermal area, but otherwise the volcano seemed to be undisturbed. In March and April 1991, however, magma started rising towards the surface from more than 20 miles (32 kms.) beneath Pinatubo. This triggered more small earthquakes and caused powerful steam explosions that blasted three craters on the north side of the volcano. Thousands of small earthquakes occurred beneath Pinatubo throughout April, May, and early June 1991, and many thousand tons of noxious sulphur dioxide gas were also emitted by the volcano.
Scientists had been able to forecast Pinatubo's 1991 eruption and this resulted in the saving of many lives and much property. Commercial aircraft were warned about the hazard of the ash cloud from the June 15 eruption, and most avoided it. Although much equipment was successfully protected, buildings on two U.S. military bases in the Philippines--Clark Air Base and Subic Bay Naval Station--were heavily damaged by ash. Nearly 20 million tons of sulphur dioxide were injected into the stratosphere and the spread of this gas cloud around the world caused global temperatures to drop temporarily (1991-1993) by about 0.5°C. About 20,000 Aeta highlanders,
Introduction
Where: Mount Pinatubo, Philippines, Asia
When: June 12th-15th, 1991
Type of volcano: Strato or composite volcano
Type of eruption: Explosive - the second biggest eruption this century
Deaths: 300 people died, 1000's were evacuate
Mount Pinatuba had been dormant for 500 years. The first sign that this situation might be changing occured on July 16, 1990 when a magnitude 7.8 earthquake (roughly the size of the 1906 San Francisco earthquake) struck about 60 miles (100 kms.) northeast of Mount Pinatubo on the island of Luzon in the Philippines. This caused the shaking and squeezing of the Earth's crust beneath the volcano. At Mount Pinatubo, scientists recorded a landslide, some local earthquakes, and a short-lived increase in steam emissions from a pre-existing geothermal area, but otherwise the volcano seemed to be undisturbed. In March and April 1991, however, magma started rising towards the surface from more than 20 miles (32 kms.) beneath Pinatubo. This triggered more small earthquakes and caused powerful steam explosions that blasted three craters on the north side of the volcano. Thousands of small earthquakes occurred beneath Pinatubo throughout April, May, and early June 1991, and many thousand tons of noxious sulphur dioxide gas were also emitted by the volcano.
Scientists had been able to forecast Pinatubo's 1991 eruption and this resulted in the saving of many lives and much property. Commercial aircraft were warned about the hazard of the ash cloud from the June 15 eruption, and most avoided it. Although much equipment was successfully protected, buildings on two U.S. military bases in the Philippines--Clark Air Base and Subic Bay Naval Station--were heavily damaged by ash. Nearly 20 million tons of sulphur dioxide were injected into the stratosphere and the spread of this gas cloud around the world caused global temperatures to drop temporarily (1991-1993) by about 0.5°C. About 20,000 Aeta highlanders,