Environmental Engineering Reference
In-Depth Information
Map of quaternary traces
Point of nearest approach to
nuclear power plant
Nuclear power plant
location
Control width of fault
Width or zone requiring detailed
faulting investigations (1 4
times control width)
FIGURE 11.45
Diagrammatic illustration of
delineation of width of zone requiring
detailed faulting investigations for the
specific Nuclear Power Plant location.
(From NRC, Appendix A to Part 100,
2003. With permission.)
Control width of fault
TABLE 11.18
Determination of Zone Requiring Detailed Faulting Investigation a
Magnitude of Earthquake
Width of Zone of Detailed Study
Less than 5.5
1
control width
5.5-6.4
2
control width
6.5-7.5
3
control width
Greater than 7.5
4
control width
a
From NRC, Appendix A to Part 100, U.S. Nuclear Regulatory Commission, 2003.
It is assumed that the focus, whether the intensity is selected from the recurrence analy-
sis or is based on possible rupture length, will be located at the closest point on the capa-
ble fault. This is considered a reasonable assumption for shallow-focus events.
Attenuation : Peak acceleration for rock excitation at the site, in terms of g , is estimated
by attenuation from the fault ( Section 11.3.1 ). One relationship as given in Figure 11.28.
Attenuation relationships have been developed by numerous investigators who are listed
in Table 3-1 of EM 1110-2-6050 (USAEC, 1999). The table is a plot of 16 investigator refer-
ences vs. site condition (soil and rock) for western U.S. shallow earthquakes, eastern U.S.
earthquakes, and subduction zone (plate edge) earthquakes.
The earthquake considered in planning the ultimate design is usually the largest that
might occur at the closest approach to the site of any capable fault. Judgment is used in the
selection of the design event; main considerations are recurrence probability and magnitude.
 
 
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