Pinatubo, Philippines

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.