2008 National Seismic Hazard Maps

2008 National Seismic Hazard Maps-Fault parameters

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Fault Name	State
Oquirrh-Southern Oquirrh Mountains fault zone	Utah

GEOMETRY
Dip (degrees)	50/40/60
Dip direction	W
Sense of slip	normal
Rupture top (km)	0
Rupture bottom (km)	15
Rake (degrees)	-90
Length (km)	63

MODEL VALUES
Probability of activity	1
Minimum magnitude	6.5
Maximum magnitude	7.17
b-value	0.8

Assigned Dip	Fault-Parallel Slip Rate	Width	Annual Rate	a-value	Branch Weight
40	0.31	23.3	2.17e-04	1.508	0.2
50	0.26	19.6	1.53e-04	1.355	0.6
60	0.23	17.3	1.19e-04	1.249	0.2

Comments
We follow the recommendation by the Utah Quaternary Fault Parameter Working Group (Lund, 2005) to extend the Oquirrh fault to the south to include the Southern Oquirrh Mountains fault zone as a single integrated structure and that the combined source be assigned the consensus slip rate of 0.2 mm/yr based on original investigation by Olig and others (2001). Dip of fault changed to 50? based on redefined regional default value (Lund, 2006).

Comments

We follow the recommendation by the Utah Quaternary Fault Parameter Working Group (Lund, 2005) to extend the Oquirrh fault to the south to include the Southern Oquirrh Mountains fault zone as a single integrated structure and that the combined source be assigned the consensus slip rate of 0.2 mm/yr based on original investigation by Olig and others (2001). Dip of fault changed to 50? based on redefined regional default value (Lund, 2006).

Selected References
Olig, S.S., Lund, W.R., Black, B.D., and Mayes, B.H., 1996, Paleoseismology of Utah, volume 6—Paleoseismic investigation of the Oquirrh fault zone, Tooele County, Utah, in Lund, W.R., ed., The Oquirrh fault zone, Tooele County, Utah—Surficial geology and paleoseismicity: Utah Geological Survey Special Study 88, p. 18-64, 1 pl., scale 1:24,000, http://ugspub.nr.utah.gov/publications/special_studies/SS-88.pdf. Olig, S.S., Gorton, A.E., Black, B.D., and Forman, S.L., 2001, Paleoseismology of the Mercur fault and segmentation of the Oquirrh-East Great Salt Lake fault zone, Utah: Technical report to U.S. Geological Survey, Reston, Virginia, under Contract 98HQGR1036, January 25, 2001, variously paginated. Lund, W.R., 2005, Consensus preferred recurrence interval and vertical slip rate estimates—Review of Utah paleoseismic-trenching data by the Utah Quaternary Fault Parameters Working Group: Utah Geological Survey Bulletin 134, compact disk. Wong, I., Silva, W., Olig, S., Thomas, P., Wright, D., Ashland, F., Gregor, N., Pechmann, J., Dober, M., Christenson, G., and Gerth, R., 2002, Earthquake scenario and probabilistic ground shaking maps for the Salt Lake City, Utah metropolitan area: Utah Geological Survey Miscellaneous Publication 02-5, 50 p., compact disk.

Selected References

Olig, S.S., Lund, W.R., Black, B.D., and Mayes, B.H., 1996, Paleoseismology of Utah, volume 6—Paleoseismic investigation of the Oquirrh fault zone, Tooele County, Utah, in Lund, W.R., ed., The Oquirrh fault zone, Tooele County, Utah—Surficial geology and paleoseismicity: Utah Geological Survey Special Study 88, p. 18-64, 1 pl., scale 1:24,000, http://ugspub.nr.utah.gov/publications/special_studies/SS-88.pdf.
Olig, S.S., Gorton, A.E., Black, B.D., and Forman, S.L., 2001, Paleoseismology of the Mercur fault and segmentation of the Oquirrh-East Great Salt Lake fault zone, Utah: Technical report to U.S. Geological Survey, Reston, Virginia, under Contract 98HQGR1036, January 25, 2001, variously paginated.
Lund, W.R., 2005, Consensus preferred recurrence interval and vertical slip rate estimates—Review of Utah paleoseismic-trenching data by the Utah Quaternary Fault Parameters Working Group: Utah Geological Survey Bulletin 134, compact disk.
Wong, I., Silva, W., Olig, S., Thomas, P., Wright, D., Ashland, F., Gregor, N., Pechmann, J., Dober, M., Christenson, G., and Gerth, R., 2002, Earthquake scenario and probabilistic ground shaking maps for the Salt Lake City, Utah metropolitan area: Utah Geological Survey Miscellaneous Publication 02-5, 50 p., compact disk.