HR: 17:00h
AN: U22C-05    [PDF]
TI: Estimation of Future Earthquake Losses in California
AU: * Rowshandel, B
EM: browshan@consrv.ca.gov
AF: California Geological Survey, 801 K Street ms 12-32, Sacramento, CA 95814 United States
AU: Wills, C J
EM: cwills@consrv.ca.gov
AF: California Geological Survey, 801 K Street ms 12-32, Sacramento, CA 95814 United States
AU: Cao, T
EM: tcao@consrv.ca.gov
AF: California Geological Survey, 801 K Street ms 12-32, Sacramento, CA 95814 United States
AU: Reichle, M
EM: mreichle@consrv.ca.gov
AF: California Geological Survey, 801 K Street ms 12-32, Sacramento, CA 95814 United States
AU: Branum, D
EM: dbranum@consrv.ca.gov
AF: California Geological Survey, 801 K Street ms 12-32, Sacramento, CA 95814 United States
AB: Recent developments in earthquake hazards and damage modeling, computing, and data management and processing, have made it possible to develop estimates of the levels of damage from earthquakes that may be expected in the future in California. These developments have been mostly published in the open literature, and provide an opportunity to estimate the levels of earthquake damage Californians can expect to suffer during the next several decades. Within the past 30 years, earthquake losses have increased dramatically, mostly because our exposure to earthquake hazards has increased. All but four of the recent damaging earthquakes have occurred distant from California's major population centers. Two, the Loma Prieta earthquake and the San Fernando earthquake, occurred on the edges of major populated areas. Loma Prieta caused significant damage in the nearby Santa Cruz and in the more distant, heavily populated, San Francisco Bay area. The 1971 San Fernando earthquake had an epicenter in the lightly populated San Gabriel Mountains, but caused slightly over 2 billion dollars in damage in the Los Angeles area. As urban areas continue to expand, the population and infrastructure at risk increases. When earthquakes occur closer to populated areas, damage is more significant. The relatively minor Whittier Narrows earthquake of 1987 caused over 500 million dollars in damage because it occurred in the Los Angeles metropolitan area, not at its fringes. The Northridge earthquake had fault rupture directly beneath the San Fernando Valley, and caused about 46 billion dollars in damage. This vast increase in damage from the San Fernando earthquake reflected both the location of the earthquake directly beneath the populated area and the 23 years of continued development and resulting greater exposure to potential damage. We have calculated losses from potential future earthquake, both as scenarios of potential earthquakes and as annualized losses considering all the potential earthquake sources included in the national seismic hazard maps. Initial results give an expected annual loss in California of 2.2 billion dollars. This estimate is based on the 2002 CGS-USGS ground motion data and the 1997 NEHRP soil amplification factors. It should be pointed out that these results are very sensitive to the soil amplification factors used in the analysis. Using amplification factors from Boore, Joyner and Fumal, 1997, which had been used in previous CGS loss estimation studies, the state wide estimated annual loss becomes roughly 3.3 billion dollars. The estimates presented in this study include only structural and non-structural damage to buildings. Experience with real earthquakes suggest that when associated losses, such as losses to contents, inventory and income, are included, the total expected annual would be considerably larger.
DE: 6334 Regional planning
DE: 7223 Seismic hazard assessment and prediction
SC: U
MN: 2003 Fall Meeting