As part of a program that FEMA and its predecessor agencies have had underway for a number of years, property loss and casualty estimates were prepared in 1972 and 1973 for a number of potential maximum credible earthquakes that could impact on the San Francisco and the Los Angeles areas--North San Andreas (Richter magnitude 8.3), Hayward (Richter magnitude 7.4), South San Andreas (Richter magnitude 8.3), and Newport-Inglewood (Richter magnitude 7.5). These estimates have now been updated as part of the current assessment. Estimates of property loss and casualties are based on the expected type and distribution of damage for each postulated earthquake as determined by the size and location of the earthquake and the distribution and character of the buildings and structures within the affected area. Methodologies for estimates of this type are approximate at best. Consequently, the figures shown below may vary upward or downward by as much as a factor of two or three. This degree of uncertainty does not affect the validity of the conclusions of this report, however, since there are greater uncertainties in all other aspects of emergency response planning. B. PROPERTY LOSS ESTIMATES The property loss estimates were obtained by first estimating the total replacement dollar value of buildings and their contents, multiplying them by percentage loss factors (inferred from the anticipated strength of shaking in each county), and then summing to obtain the aggregate loss. Included in the estimates are private as well as Federal, State, and local government buildings, insured and uninsured. Excluded from consideration is the replacement value of transportation and communication facilities, dams, utility installations, and special purpose structures (e.g., convention centers and sports arenas). Also excluded is the potential damage resulting from a major dam failure or the indirect dollar losses due to such factors as higher unemployment, lower tax revenue, reduced productivity, and stoppage of industrial production. Experience indicates that indirect losses could be approximately equal to the dollar amounts lost in buildings and their contents. The property loss estimates for four postulated earthquakes on the faults listed below are as follows. TABLE 2 ESTIMATES OF PROPERTY LOSSES FOR REPRESENTATIVE EARTHQUAKES[1]