EFFECTS

Detailed maps were prepared for each event showing qualitative
estimates of ground shaking intensity resulting from each earthquake.
These estimates are indicative of the general severity of damage to
ordinary structures. Empirical formulae providing quantitative
estimates of peak ground motion at various distances from the
postulated earthquakes were developed for use in the effects of
severe ground shaking on individual structures or critical
facilities. No estimates were made of localized effects, such as
ground failures related to liquefaction (the complete failure or loss
of strength, of a saturated soil due to shaking), landslides, and
fault rupture. These effects can be far more destructive than ground
shaking alone.

[Illustration: Figure 1. Geographic Locations of Selected Regional
Events]

CHAPTER III

ASSESSMENT OF LOSSES FOR SELECTED POTENTIAL CALIFORNIA EARTHQUAKES

A. INTRODUCTION

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