The effects of any earthquake depend on a number of videly varying
factors. These factors are all of:
- Intrinsic to the earthquake - its
magnitude, type, location, or depth;
- Geologic conditions where effects
are felt - distance from the event, path of the seismic waves, types
of soil, water saturation of soil; and
- Societal conditions reacting to
the earthquake - quality of construction, preparedness of populace, or
time of day (e.g.: rush hour).
One can count the number of deaths caused by
large earthquakes to compare the results of all these disparate factors in
combination. The Oct. 17, 1989 Loma Prieta earthquake occurred in
the least-populated area of the generally urban San Francisco peninsula.
Construction standards in the area are relatively high, and the populace
relatively prepared. However, soft, highly-saturated soils near San
Francisco Bay caused some spectacular failures of large highway structures
unusually far away from the event. Even though it was rush hour, many
fewer cars were on the roads due to the start of the opening game of the
World Series, being played locally. Thus deaths were limited to about 75.
On the other hand, the same year an
earthquake of nearly identical energy struck the war-torn country of Armenia,
between Russia and Turkey. It was located much closer to the major cities
of the region, where poorly-engineered houses of unreinforced concrete
collapsed on their occupants during the night. The number of fatalities
passed 25,000. |