Within the past five years, the international community has recognized that it may be possible, through programs of systematic study, to devise means to reduce and mitigate the occurrence of a variety of devastating natural hazards. Among these disasters are earthquakes, volcanic eruptions, floods, and landslides. The importance of these studies is underscored by the fact that within fifty years, more than a third of the world's population will live in seismically and volcanically active zones. The International Council of Scientific Unions, together with UNESCO and the World Bank, have...