DESCRIPTION:
The USGS/OFDA Volcano Disaster Assistance Program

[Map,139K,InlineGIF] Map, Principal Volcanic Regions of the World and VDAP Responses 1987-1999 -- UPDATED from: Ewert, et.al., 1997, USGS Fact Sheet 064-97

Following the tragic 1985 eruption of Nevado del Ruiz Volcano, Colombia, in which over 23,000 people lost their lives, the USGS and OFDA began the Volcano Disaster Assistance Program (VDAP). The primary mission of this interagency cooperative program is to reduce eruption-caused fatalities and economic losses in developing countries. The principal components of VDAP are operational funding from OFDA, a small core group of scientists at the USGS' Cascades Volcano Observatory (CVO) in Vancouver, Washington, a large group of contributing scientists from CVO and other USGS offices, and a cache of portable volcano-monitoring equipment ready for rapid deployment.

The strategy employed by VDAP to reduce loss of life and minimize economic disruption includes instrumental monitoring to detect the movement of magma (molten rock) toward the surface and thereby forecast eruptions, and assessments of volcano hazards and risk based on past eruptive events at a volcano.

A great majority of the world's potentially active volcanoes are unmonitored. Less than twenty-five percent of volcanoes that are known to have had eruptions in historical time are monitored at all, and, of these, only about two dozen are thoroughly monitored. Moreover, seventy-five percent of the largest explosive eruptions since 1800 occurred at volcanoes that had no previous historical eruptions (Simkin and Siebert, 1994). Thus, until regular volcano surveillance is much more widespread, a mobile crisis-response capability is needed to quickly assess hazards and install monitoring equipment when a volcano becomes restless. Otherwise, tragedies like the one at Nevado del Ruiz will be repeated.

On April 2, 1991, after being dormant for 500 years, Mount Pinatubo volcano in the Philippines awoke with a series of steam explosions and earthquakes. Ten weeks later, on the morning of June 15th, Pinatubo exploded in a climactic volcanic eruption. Fiery avalanches of hot ash (pyroclastic flows) roared down the flanks of the volcano, and giant mudflows of ash (lahars) swept more than 30 miles down valleys. Cities and towns near Pinatubo were devastated by falling ash. Ash fall also inundated the two largest U.S. military bases in the Philippines. On Clark Air Force Base, which was home to more than 15,000 American servicemen and dependents, many buildings collapsed under the weight of rain-saturated ash. Facilities at the U.S. Naval Station at Subic Bay, 25 miles from Pinatubo, were also severely damaged.

Despite the enormity of the devastation wrought by this explosive eruption, quick work by earth scientists helped keep the death toll low. Shortly after Mount Pinatubo's reawakening, U.S. Geological Survey (USGS) scientists with the Volcano Disaster Assistance Program's crisis response team arrived at Clark Air Force Base. Once on the scene, they joined scientists from the Philippine Institute of Volcanology and Seismology, who had begun monitoring the volcano. This joint team worked quickly to evaluate the threat from Pinatubo, installing instruments to detect earthquakes and swelling on the mountain and mapping volcanic deposits in order to understand the volcano's eruptive history. Their evaluation enabled them to alert people in areas at risk and also provide critical advice to the Philippine Government and to U.S. military commanders at Clark Air Force Base and Subic Bay.

When data from monitoring instruments indicated that a large eruption was imminent, the scientists issued timely warnings that resulted in safe evacuation of more than 75,000 people before the volcano's climactic June 15 eruption. In addition to the thousands of lives saved, hundreds of millions of dollars in military aircraft and hardware were moved out of harm's way.

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