USGS Bulletin 2188, Chapter 7
FieldElements Trip of5 Engineering Geology on the San Francisco Peninsula—Challenges When Dynamic Geology and Society’s Transportation Web Intersect Elements of Engineering Geology on the San Francisco Peninsula— Challenges When Dynamic Geology and Society’s Transportation Web Intersect John W. Williams Department of Geology, San José State University, Calif. Introduction The greater San Francisco Bay area currently provides living and working space for approximately 10 million residents, almost one-third of the population of California. These individuals build, live, and work in some of the most geologically dynamic terrain on the planet. Geologically, the San Francisco Bay area is bisected by the complex and active plate boundary between the North American and Pacific Plates prominently marked by the historically active San Andreas Fault. This fault, arguably the best known and most extensively studied fault in the world, was the locus of the famous 1906 San Francisco earthquake and the more recent 1989 Loma Prieta earthquake. There is the great potential for property damage and loss of life from recurring large-magnitude earthquakes in this densely populated urban setting, resulting from ground shaking, ground rupture, tsunamis, ground failures, and other induced seismic failures. Moreover, other natural hazards exist, including landslides, weak foundation materials (for example, bay muds), coastal erosion, flooding, and the potential loss of mineral resources because of inappropriate land-use planning. The risk to humans and their structures will inexorably increase as the expanding San Francisco Bay area urban population continues to encroach on the more geologically unstable lands of the surrounding hills and mountains. One of the critical elements in the development of urban areas is the requirement that people and things have the ability to move or be moved from location to location.
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