ong duration of shaking could trigger numerous slides on steep
slopes and cause liquefaction in isolated areas.
2. San Francisco Bay Area/Northern San Andreas Fault
(Magnitude 8.3)
A repeat occurrence of the 1906 earthquake, in which the San
Andreas fault broke over 400 km of its length, would cause severe
damage to structures throughout the Bay Area and adjacent regions. The
extensive urban development on lowlands and landfill around San
Francisco Bay would be especially hard hit and liquefaction in many of
these areas would intensify the damage to structures erected on them.
3. San Francisco Bay Area/Hayward Fault (Magnitude 7.4)
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
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