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50˚
40˚
NMSZ
> 6.0
5−5.99
4−4.99
CHSZ
3−3.99
< 3.0
km
30˚
0
500
−100˚
−90˚
−80˚
−70˚
Figure 12.1 CEUS earthquake catalog determined for the CEUS SSC Project (Coppersmith et al .,
2012 ) . The CEUS-SSC Catalog is modified to include a M5.2 inferred triggered earthquake near
Louisville, Kentucky, which occurred at 10:40 LT on February 7, 1812 (Hough, 2001 ) , and to revise
the magnitude of the 1843 Marked Tree, Arkansas, earthquake from 6.0 to 5.4 (Hough, 2013 ) .
times, (2) GPS results provide an increasingly tight (and low) bound on strain accrual rates,
and (3) extensive research has focused on both the magnitudes and the recurrence rates
of the (assumed) characteristic earthquakes. Moreover, efforts to understand intraplate
seismogenesis, both in the CEUS and more generally, have focused largely on reconciling
the apparent paradox posed by high rates of moment release versus a low rate of strain
accrual. Research results to date as well as the conclusions of this chapter are expected
to have general applicability for low strain rate regions, although, as I discuss later in
the chapter, there appear to be some differences in the nature of seismicity characteristics
between intraplate regions.
12.2 Seismic moment release in the Central/Eastern United States
12.2.1 Historical earthquakes: introduction and rupture scenarios
Moderate earthquakes have occurred in many regions in the CEUS during the
300-year
historical record ( Figure 12.1 ) . However, according to all recent characterizations, overall
 
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