Civil Engineering Reference
In-Depth Information
FIGURE 2.17
Locations of Alaskan earthquakes causing damage from 1750 to 1996 and having a modi-
fied Mercalli intensity of VI to XII. See Fig. 2.16 for intensity legend. (
Prepared by USGS National
Earthquake Information Center.
)
2.4
Assume that a seismograph, located 1200 km from the epicenter of an earthquake,
records a maximum ground displacement of 15.6 mm for surface waves having a period of
20 seconds. Based on these assumptions, determine the surface wave magnitude.
Answer:
M
s
7.9.
2.5
Assume that during a major earthquake, the depth of fault rupture is estimated to
be 15 km, the length of surface faulting is determined to be 600 km, and the average slip
along the fault is 2.5 m. Based on these assumptions, determine the moment magnitude.
Use a shear modulus equal to 3
10
10
N/m
2
.
Answer:
M
w
8.0.
Earthquake Intensity
2.6
Suppose that you are considering buying an house located in Half Moon Bay,
California. The house can be classified as a well-designed frame structure. For a repeat of
