VOLCANIC DISASTER MITIGATION IN THE PHILIPPINES - EXPERIENCE FROM MT-PINATUBO

Considerable progress has been made in volcanic disaster mitigation in the Philippines during the last four decades, since the devastating H ibok-Hibok eruption in 1951 and the establishment of the Commission on Volcanology (COMVOL), the forerunner of the Philippine Institute of V olcanology and Seismology (PHIVOLCS) in 1952. The management of the Pi natubo Volcano eruption crisis of 1991-92 marks the highest point in t he development of volcanic disaster mitigation in the country. State-o f-the-art volcano monitoring techniques and instruments were applied; the eruption was accurately predicted; hazards zonation maps were prep ared and disseminated a month before the violent explosions; an alert and warning system was designed and implemented; and the disaster resp onse machinery was mobilized on time. The unprecedented magnitude and lingering nature of the hazards, however, and their widespread, long-t erm impacts have sorely tested the capability of the country's volcani c disaster mitigation systems. In particular, the lahar threat has tri ggered controversies and put decision makers in a dilemma of choosing between adaptive versus confrontational/control approaches. At least t hree strategies have been articulated and adopted in varying degrees a nd forms: (1) the establishment of a lahar monitoring-warning-evacuati on system to deal with the lahar problem on an emergency basis; (2) re location of settlements from the hazard zones; and (3) installation of engineering countermeasures to control/divert the lahar flows and pro tect settlements. A combination of the three appears to be the best, b ut the most effective and least costly mix remains to be determined.