First 331 words of the document:
Pinatubo - a volcanic disaster averted in the Philippines
Source: USGS (1992)
On April 2nd 1991 small explosions followed by steaming and the smell of rotten eggs was
seen coming from the slopes of Mount Pinatubo (a dormant volcano last eruption 600
years ago). Within 10 weeks there would be an eruption that has been the most explosive of
the twentieth century reaching VEI 5.
THE PHILIPPINE INSTITUTE OF VOLCANOLOGY AND SEISMOLOGY immediately
installed portable seismometers and began recording several hundred earthquakes a day.
The USGS arrived on April 23rd and within 2 weeks had installed a radio-telemetred
seismic network capable of locating the increasing number of earthquakes.
Risk mapping: Philippine and American geologists made a geological reconnaissance of
the volcano and established a set of alert levels ranging from 1 to 5. Small villages on the
volcano's northwest slope and part of Clark Air Base lay within the potential range of
pyroclastic flows. A hazard map was prepared and distributed to local officials by May 23rd
showing virtually all of the hazards subsequently
encountered when Pinatubo erupted.
On June 12th the first of several major explosions
took place, sending airborne ash to the west and
pyroclastic flows down the northwest slope of the
volcano. A climatic eruption took place on 15th
June during the passage of a typhoon. The
typhoon compounded the effects of the eruption
by generating mud flows in addition to ash fall and
greatly hampering evacuation efforts.
However, given the size of the eruption the death toll was remarkably low 350 people died,
mainly in buildings that collapsed. The alert system put in place by PHIVOLCS combined
with effective communication among the USGS, local civil defence agencies and the
US military prevented a much greater human disaster. There was excellent
management involving the wide range of different players that cooperated in a coordinated