Proceedings of the Geologic and Hydrologic Hazards Training Program

Abstract

FOREWORDThe complex nature of man encompasses a desire for the gifts of peace, the will to wage war, and magnanimity toward his fellow in misfortune. As institutions and governments of man reflect these traits, the Office of Foreign Disaster Assistance of the Agency for International Development acts to carry out the deep-seated humanitarian concern that the people of the United States have for the unfortunate victims of natural and manmade calamities in other nations.In the case of natural disasters, it is now widely recognized that mitigative and preparatory steps taken before the event are the key to the ability of a region or a community to survive and restore its normal functions within a short time after the disaster. The Office of Foreign Disaster Assistance recognized this fact and provided funds to the Geological Survey of the United States to conduct a training course on geologic and hydrologic hazards reduction for scientists and officials from other countries. Those countries invited to participate either have experienced or may be subject to the ravages of floods, earthquakes, volcanic eruptions, and landslides. This document is a report of that course.,""^e purpose of the course was to provide a vehicle for the diffusion of knowledge and experience gained in the United States through hazard reduction programs and in response to actual events. The course addressed basic questions: what are the physical effects of these events, how can these effects be avoided, and how can these effects be reduced if not avoided. We believe that the training course advanced the complex process of information gathering, research, and analysis that will answer these questions for each participant.We hope that this effort ultimately will lead to actions that reduce loss and suffering in hazard-prone regions and increase the spirit of goodwill between nations. The geological and geophysical data available for hazard estimation must be carefully reviewed. Emphasis here is on the word available. The type and quality of the information will control the reliability of the hazard evaluation. The following is a listing of data that, ideally, are needed for hazard evaluation. SeismicityA. Earthquake Catalog -A reliable earthquake catalog containing the hypocenter, size, and description of the distribution of shaking (usually given in terms of intensity) of the earthquakes. Ideally, additional data such as the focal mechanism, evidence of surface rupture (or lack of it), seismic moment and/or magnitude should also be available.B. Geological evidence of earthquake activity (fault slip data). Seismotectonic featuresCareful geologic mapping, particularly of Quaternary geology, with particular emphasis on historic and Holocene faulting, should be assembled if available. Division of areas into Seismotectonic provinces is desirable (see references in paper by Thenhaus). Many types of geophysical data such as high resolution seismic reflection surveys, gravity and magnetic maps, and seismic refraction surveys may be useful in delineat...