The last large events to occur on this fault were in 1836 and 1868. Should a major earthquake occur, severe ground shaking and liquefaction is expected to cause damage throughout the entire circum-bay area nearly as severe as that resulting from a 1906-type earthquake on the San Andreas fault. This earthquake would be of particular concern because of the many dams located along or near the fault. 4. Los Angeles/Newport-Inglewood Fault (Magnitude 7.5) This earthquake would be a serious threat to the nearby, densely-populated areas of Los Angeles. Shaking would cause extensive structural damage throughout the Los Angeles Basin and liquefaction near the coast would add still more destruction. 5. San Diego Area/Rose Canyon Fault (Magnitude 7.0) This fault--a segment of an active zone of faults extending from the Newport-Inglewood fault to Northern Mexico--would present the greatest earthquake risk to the San Diego area. Severe damage due to shaking and liquefaction could be expected in the coastal areas. Because of unstable sea-bed sediments in the offshore area, local tsunamis (tidal waves) are possible. 6. Los Angeles/Santa Monica Fault (Magnitude 6.7 and 7.0) and Riverside/San Bernardino/Cucamonga Fault (Magnitude 6.8) These faults are part of a system of east-west tending faults bordering the northern edge of the Los Angeles basin. This fault system caused the 1971 San Fernando earthquake and is geologically similar to the system that generated the large 1952 Kern County earthquake. Although smaller in magnitude than the earthquakes previously described, these postulated events are potentially quite dangerous because of their vicinity to high population densities in Southern California. D. EARTHQUAKE 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