ESTIMATES OF PROPERTY LOSSES FOR REPRESENTATIVE EARTHQUAKES[1]

FaultLoss to Building
($ in Billions)
Loss of Contents
($ in Billions)
Total Loss
($ in Billions)
Northern San Andreas251338
Hayward291544
Newport-Inglewood452469
Southern San Andreas11 617

[1] Uncertain by a possible factor of two to three.

C. CASUALTY ESTIMATES

Deaths and injuries in these earthquakes principally would occur from failures of man-made structures, particularly older, multistory, and unreinforced brick masonry buildings built before the institution of earthquake-resistant building codes. Experience has shown that some modern multistory buildings—constructed as recently as the late 1960's, but not adequately designed or constructed to meet the current understanding of requirements for seismic resistance—are also subject to failure. Consequently, the number of fatalities will be strongly influenced by the number of persons within high-occupancy buildings, capable of collapsing, or by failure of other critical facilities such as dams. Additional imponderables are the degree of saturation of the ground at the time of the event and the possibility of weather conditions 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]

FaultTimeDeadHospitalized[2]
Northern San Andreas2:30 a.m.
2:00 p.m.
4:30 p.m.
3,000
10,000
11,000
12,000
37,000
44,000
Hayward2:30 a.m.
2:00 p.m.
4:30 p.m.
3,000
8,000
7,000
13,000
30,000
27,000
Southern San Andreas2:30 a.m.
2:00 p.m.
4:30 p.m.
3,000
12,000
14,000
12,000
50,000
55,000
Newport-Inglewood2:30 a.m.
2:00 p.m.
4:30 p.m.
4,000
21,000
23,000
18,000
83,000
91,000

[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.

D. OVERVIEW OF OTHER TYPES OF DAMAGE