2008 National Seismic Hazard Maps

2008 National Seismic Hazard Maps-Fault parameters

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Fault Name	State
Greys River fault	Wyoming

GEOMETRY
Dip (degrees)	40/60/50
Dip direction	W
Sense of slip	normal
Rupture top (km)	0
Rupture bottom (km)	15
Rake (degrees)	-90
Length (km)	50

MODEL VALUES
Probability of activity	1
Minimum magnitude	6.5
Maximum magnitude	7.05
b-value	0.8

Assigned Dip	Fault-Parallel Slip Rate	Width	Annual Rate	a-value	Branch Weight
40	0.97	23.3	8.01e-04	1.944	0.2
50	0.81	19.6	5.64e-04	1.792	0.6
60	0.72	17.3	4.41e-04	1.685	0.2

Comments
The preferred vertical slip rate is derived from 9.3 m of slip in the past 15 k.y. (Jones and McCalpin, 1992; McCalpin, 1993). Dip of fault changed to 50? based on redefined regional default value (Lund, 2006).

Selected References
Lund, W.R., ed., 2006, Basin and Range Province Earthquake Working Group seismic-hazard recommendations to the U.S. Geological Survey National Seismic Hazard Mapping Program: Utah Geological Survey Open-File Report 477, 23 p, ugspub.nr.utah.gov/publications/open_file_reports/OFR-477.pdf. McCalpin, J.P., 1993, Neotectonics of the northeastern Basin and Range margin, western USA: Zeitschrift fuer Geomorphologie N. Folge, v. 94, p. 137-157. Jones, L.C.A., and McCalpin, J.P., 1992, Quaternary faulting on the Grey's River fault, a listric normal fault in the overthrust belt of Wyoming: Geological Society of America Abstracts with Programs, v. 24, no. 6, p. 20.

Selected References

Lund, W.R., ed., 2006, Basin and Range Province Earthquake Working Group seismic-hazard recommendations to the U.S. Geological Survey National Seismic Hazard Mapping Program: Utah Geological Survey Open-File Report 477, 23 p, ugspub.nr.utah.gov/publications/open_file_reports/OFR-477.pdf.
McCalpin, J.P., 1993, Neotectonics of the northeastern Basin and Range margin, western USA: Zeitschrift fuer Geomorphologie N. Folge, v. 94, p. 137-157.
Jones, L.C.A., and McCalpin, J.P., 1992, Quaternary faulting on the Grey's River fault, a listric normal fault in the overthrust belt of Wyoming: Geological Society of America Abstracts with Programs, v. 24, no. 6, p. 20.