Environmental Engineering Reference
In-Depth Information
2.12
Earthquake magnitudes and energy releases. Fatalities
in parentheses. Plotted from Ruff (1996).
(M
W
9.5) was felt for 340 s (Ni, Kanamori, and Helm-
berger 2005).
Magnitudes and approximate seismic energies of major
earthquakes that struck between 1900 and 2005 do not
correlate with fatalities (fig. 2.12): the population den-
sities of the stricken areas and the quality of construction
are far more important. The September 1, 1923, Kant
¯
earthquake that set Tokyo on fire claimed more than 40
times as many lives as did the April 18, 1906, San Fran-
cisco earthquake, which released roughly four times as
much energy. The highest death toll caused by an earth-
quake was in Tangshan on July 28, 1976: the Maoist
regime reported officially 242,219 fatalities in that north-
ern Chinese coal-mining city, but estimates of the actual
death toll are as high as 655,000 (Huixian et al. 2002).
Even with low fatalities, urban densities guarantee
costly material damage and massive homelessness: the
January 17, 1995, Kobe (Hy
¯
goken Nanbu) quake killed
5,470, displaced 310,000 people, and cost at least $110
billion in damage (Chung et al. 1996). During the twen-
tieth century, earthquakes caused more deaths than vol-
canic eruptions, floods, and cyclones combined. Because
