Aerial view of Mount Pinatubo after the cataclysmic June 15, 1991. A
joint team from the
US Geological Survey and the Philippine Institute of Volcanology and Seismology
(PHIVOLCS) worked closely to assess hazards and monitor and predict eruptive activity at
Mount Pinatubo in 1991. The accurate characterization of the hazards and timely warnings
of eruptions led to the evacuation of approximately 56,000 people--including 14,500 U.S.
servicemen and their dependents--from high-hazard areas near Mount Pinatubo days
before the volcano's climactic eruption. Photo by E.W. Wolfe.
Seismograph in action at Pinatubo response. Signals from some
seismometers are always
recorded on analog drum recorders. Despite advances in computer-based data acquisition,
drum recorders are still needed. A glance at the seismogram wrapped around the drum
gives experienced volcanologists a quick appreciation of the current level of seismic
activity at the volcano. Photo by R.P. Hoblitt.
Photos courtesy of USGS Cascades Volcano Observatory.