2008 National Seismic Hazard Maps

2008 National Seismic Hazard Maps-Fault parameters

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Fault Name	State
San Francisco fault	New Mexico

GEOMETRY
Dip (degrees)	40/50/60
Dip direction	W
Sense of slip	normal
Rupture top (km)	0
Rupture bottom (km)	15
Rake (degrees)	-90
Length (km)	28

MODEL VALUES
Probability of activity	1
Minimum magnitude	6.5
Maximum magnitude	6.76
b-value	0.8

Assigned Dip	Fault-Parallel Slip Rate	Width	Annual Rate	a-value	Branch Weight
40	0.10	23.3	1.25e-04	1.291	0.2
50	0.08	19.6	8.77e-05	1.139	0.6
60	0.07	17.3	6.86e-05	1.032	0.2

Comments
The San Francisco fault was assigned a vertical slip rate of 0.07 mm/yr in the 1996 national seismic hazard maps. There were and still are no fault-specific data from which to calculate slip rates, no scarps are reported on Quaternary deposits, and authors disagree about suggested evidence for Quaternary offsets. The assigned vertical slip rate (adjusted for fault dip) is from Wong and others (1995, 1996), who, by analogy, assigned this fault the same fault-parallel slip rate they had calculated for the La Bajada fault. Dip of fault changed to 50? based on redefined regional default value (Lund, 2006).

Comments

The San Francisco fault was assigned a vertical slip rate of 0.07 mm/yr in the 1996 national seismic hazard maps. There were and still are no fault-specific data from which to calculate slip rates, no scarps are reported on Quaternary deposits, and authors disagree about suggested evidence for Quaternary offsets. The assigned vertical slip rate (adjusted for fault dip) is from Wong and others (1995, 1996), who, by analogy, assigned this fault the same fault-parallel slip rate they had calculated for the La Bajada fault. Dip of fault changed to 50? based on redefined regional default value (Lund, 2006).

Selected References
Wong, I., Kelson, K., Olig, S., Kolbe, T., Hemphill-Haley, M., Bott, J., Green, R., Kanakari, H., Sawyer, J., Silva, W., Stark, C., Haraden, C., Fenton, C., Unruh, J., Gardner, J., Reneau, S., and House, L., 1995, Seismic hazards evaluation of the Los Alamos National Laboratory: Technical report to Los Alamos National Laboratory, Los Alamos, New Mexico, February 24, 1995, 3 volumes, 12 pls., 16 appen. Wong, I., Kelson, K., Olig, S., Bott, J., Green, R., Kolbe, T., Hemphill-Haley, M., Gardner, J., Reneau, S., and Silva, W., 1996, Earthquake potential and ground shaking hazard at the Los Alamos National Laboratory, New Mexico, in Goff, F., Kues, B.S., Rogers, M.A., McFadden, L.D., and Gardner, J.N., eds., The Jemez Mountains region: New Mexico Geological Society, 47th Field Conference, September 25-28, 1996, Guidebook, p. 135–142. 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.

Selected References

Wong, I., Kelson, K., Olig, S., Kolbe, T., Hemphill-Haley, M., Bott, J., Green, R., Kanakari, H., Sawyer, J., Silva, W., Stark, C., Haraden, C., Fenton, C., Unruh, J., Gardner, J., Reneau, S., and House, L., 1995, Seismic hazards evaluation of the Los Alamos National Laboratory: Technical report to Los Alamos National Laboratory, Los Alamos, New Mexico, February 24, 1995, 3 volumes, 12 pls., 16 appen.
Wong, I., Kelson, K., Olig, S., Bott, J., Green, R., Kolbe, T., Hemphill-Haley, M., Gardner, J., Reneau, S., and Silva, W., 1996, Earthquake potential and ground shaking hazard at the Los Alamos National Laboratory, New Mexico, in Goff, F., Kues, B.S., Rogers, M.A., McFadden, L.D., and Gardner, J.N., eds., The Jemez Mountains region: New Mexico Geological Society, 47th Field Conference, September 25-28, 1996, Guidebook, p. 135–142.
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.