2008 National Seismic Hazard Maps

2008 National Seismic Hazard Maps-Fault parameters

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Fault Name	State
Rush Peak fault	Idaho

GEOMETRY
Dip (degrees)	60/50/40
Dip direction	S
Sense of slip	normal
Rupture top (km)	0
Rupture bottom (km)	15
Rake (degrees)	-90
Length (km)	29

MODEL VALUES
Probability of activity	1
Minimum magnitude	6.5
Maximum magnitude	6.78
b-value	0.8

Assigned Dip	Fault-Parallel Slip Rate	Width	Annual Rate	a-value	Branch Weight
40	0.08	23.3	9.50e-05	1.196	0.2
50	0.07	19.6	6.69e-05	1.044	0.6
60	0.06	17.3	5.23e-05	0.937	0.2

Comments
Preferred vertical slip rate based on documented 7 m offset of late Quaternary boulder leevee (Smith and others, 2001). Location of fault updated to better reflect mapping of Personius (1998). Dip of fault changed to 50? based on redefined regional default value (Lund, 2006).

Selected References
Personius, S.F., 1998, Surficial geology and neotectonics of selected areas of western Idaho and northeastern Oregon: U.S. Geological Survey Open-File Report 98-771, 25 p. Smith, S.C., Northrup, C.J., and Wood, S.H., 2001, The Rush Peak shear zone, Cuddy Mountains, western Idaho—Evidence for multiple episodes of reactivation: Geological Society of America Abstracts with Programs, v. 33, no. 5, p. 9. 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. Zollweg, J.E., and Wood, S.H., 1993, Faulting relationships, seismicity, design earthquakes, and peak ground accelerations at hydroelectric facilities in Hells Canyon of the Snake River, Idaho-Oregon: Report prepared for Idaho Power Company, 158 p., 3 pls.

Selected References

Personius, S.F., 1998, Surficial geology and neotectonics of selected areas of western Idaho and northeastern Oregon: U.S. Geological Survey Open-File Report 98-771, 25 p.
Smith, S.C., Northrup, C.J., and Wood, S.H., 2001, The Rush Peak shear zone, Cuddy Mountains, western Idaho—Evidence for multiple episodes of reactivation: Geological Society of America Abstracts with Programs, v. 33, no. 5, p. 9.
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.
Zollweg, J.E., and Wood, S.H., 1993, Faulting relationships, seismicity, design earthquakes, and peak ground accelerations at hydroelectric facilities in Hells Canyon of the Snake River, Idaho-Oregon: Report prepared for Idaho Power Company, 158 p., 3 pls.