Environmental Engineering Reference
In-Depth Information
Reno
Fort Bragg
IX
VIII-
IX
VI-VII
VIII-IX
Ukiah
V-VI
VI-VII
IV-V
VIII-IX
VII-VIII
VII-VIII
Sacramento
IX
IX
X
Napa
Santa Rosa
VII-VIII
IX
VIII
VII-VIII
VII-VIII
VII-
VIII
V-VI
IV-V
VII-
VIII
VIII-IX
Berkeley
Akland
Stockton
S A N F R A N C I S C O
IX
Hayward fault zone
VII-VIII
Calaveras fault zone
IX
Merced.
San jose
VIII-IX
San Andreas fault
VI-VIII
VIII-IX
VII-
VIII
IX
Santa Cruz
Hollister
VIII
VIII-IX
IX
Fresno
VII-VIII
Monterey
Salinas
VII-VIII
VII-VIII
0
50
100
V-VI
Scale, miles
FIGURE 11.31
Isoseismal map of the 1906 San Francisco earthquake given in the Rossi-Forel scale which roughly parallels the
modified Meracalli through I
X (see also
Figure 6.63
and
6.64).
(After Environmental Science Services
Administration, 1969; and Lawson et al., 1908.)
the southeastern United States (see
Figure 11.10)
with the geologic map of the area shows
a very strong correlation between the epicenters and faults in the zone trending SW-NE
through Tennessee, Alabama, and Georgia. The recurrence equation for the area is given
in Equation 11.14.
11.3.2
Soil Behavior
General
Excitation emanating as a stress wave from an underlying bedrock surface applies a cyclic
shearing stress to soils. On the basis of response to bedrock motions, soils are divided into
two general classes:
●
Stable soils
undergo elastic and plastic deformations but serve to dampen seismic
motion and still maintain some strength level.
Unstable soils
are subject to sudden compaction or a complete loss of strength by
cyclic liquefaction (see
Section 11.3.3)
.
●
