The 1991 eruption of Mt. Pinatubo is estimated to have produced about 1 km3 of ashfall and 7 km3 of pyroclastic flows. Much of this volcaniclastic material remains metastably perched on the flanks of the edifice. Massive lahars are expected to be generated during the wet seasons of the next several years, and possibly of the next decade. Owing to the extraordinary thickness of accumulated pyroclastic debris, hot lahars are expected to occur for the next one or two years. This presents an invaluable opportunity to study how both hot and cold rain lahars are generated and how they behave, especially how they are different from one another. This project, therefore, is intended to: (1) closely coordinate scientific observation and documentation of lahars on the west side of the volcano; (2) update lahar-hazard maps and transmit warnings when lahars are imminent; (3) train Filipino scientists to study lahars and their deposits; and (4) develop educational materials to instruct scientists, decision-makers, and laymen in the Philippines and elsewhere.
