conducive to the spread of fire. A conflagration such as
occurred in the 1906 San Francisco earthquake, is not considered
likely to occur in any of the analyzed events, however, because of
improvements in fire resistance of construction and firefighting
techniques. Nonetheless, numerous smaller fires must be anticipated in
any of the analyzed events and a "Santa Ana type" wind could cause
serious problems.
An additional element of uncertainty in estimating casualties from
earthquake stems from not knowing where most of the population will be
at the time of the earthquake. In the early morning (i.e., 2:30 a.m.)
most people are at home, by far the safest environment during a
seismic emergency. At 2:00 in the afternoon, on the other hand, the
majority of people are at their places of employment and therefore
vulnerable to collapse of office buildings. Around 4:30 p.m. many more
people are in the streets and thus subject to injury due to falling
debris or failures of transportation systems. Consequently, depending
on the time of day, wide variations in the number of casualties can be
expected.
Following are estimates of dead and injured (requiring
hospitalization) for each of the four representative faults and for
the three time periods just discussed.
TABLE 3
ESTIMATES OF CASUALTIES[1]
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Fault Time Dead Hospitalized[2]
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Northern San Andreas 2:30 a.m. 3,000 12,000
2:00 p.m. 10,000 37,000
4:30 p.m. 11,000 44,000
Hayward 2:30 a.m. 3,000 13,000
2:00 p.m. 8,000 30,000
4:30 p.m. 7,000 27,000
Southern San Andreas 2:30 a.m. 3,000 12,000
2:00 p.m. 12,000 50,000
4:30 p.m. 14,000 55,000
Newport-Inglewood 2:30 a.m. 4,000 18,000
2:00 p.m. 21,000 83,000
4:30 p.m. 23,000 91,000
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[1] Uncertain by a possible factor of two to three.
[2] Injuries not requiring hospitalization are estimated to be
from 15 to 30 times the number of deaths.
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