Seismic Safety and Land - Use Planning. Selected Examples from California. Basis for Reduction of Earthquake Hazards, San Francisco Bay Region, California

摘要

Although focusing on the 9 - county, 74,400 - square mile San Francisco Bay region in California, this study explores a problem common to all communities: how best to plan for orderly development and growth and yet conserve the natural resource base, ensure public health and safety, and minimize degradation of the natural and man - made environment. The Seismic Safety and Land - Use Planning report presents several examples from California in order to discuss the earth - science data needed for effective planning and the methods that can be used by local and regional government to reduce earthquake risk. Through various State agencies, California provides data on seismic hazards, establishes structural standards, regulates construction and operation of certain critical facilities, maintains an emergency preparedness plan, and requires cities and counties to prepare seismic safety plans. However, effective local planning is essential to reduce seismic risk. Assessing risk starts with recognizing the overall seismicity of the area and identifying potential for groundshaking, landsliding, liquefaction, surface rupture, and flooding. A ''design earthquake'' should be used as a basis for prediction. Cultural features should be inventoried and mapped, with attention to facilities such as large dams, whose failures could be disastrous, and high - occupancy structures. Using this information, officials can express risk in terms of potential dollar loss, deaths, injuries, etc., and begin formulating plans and regulations to reduce risk through local land - use planning and regulation. Methods include considering seismic hazards in analyzing land capability, developing policies consistent with seismic risk, and establishing project review procedures to ensure consideration of seismic risk. Maps, graphs, photographs, and illustrations of earthquake damage at several California sites are presented as tools for officials to use in assessing their seismic risk. References are appended. (Author abstract modified).