2008 National Seismic Hazard Maps

2008 National Seismic Hazard Maps-Fault parameters

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Fault Name	State
Hurricane fault zone (central)	Arizona

GEOMETRY
Dip (degrees)	60/40/50
Dip direction	NW
Sense of slip	normal
Rupture top (km)	0
Rupture bottom (km)	15
Rake (degrees)	-90
Length (km)	108

MODEL VALUES
Probability of activity	1
Minimum magnitude	6.5
Maximum magnitude	7.44
b-value	0.8

Assigned Dip	Fault-Parallel Slip Rate	Width	Annual Rate	a-value	Branch Weight
40	0.31	23.3	1.45e-04	1.499	0.2
50	0.26	19.6	1.02e-04	1.347	0.6
60	0.23	17.3	7.99e-05	1.240	0.2

Comments
Amoroso and others (2004) document a number of vertical slip rates using a variety of methods and datums for this part of the Hurricane fault. They state, "Slip-rate estimates using the Moriah Knoll basalt (~0.15-0.24 mm/yr; 850 ka), surface offset (~0.05-0.3 mm/yr; 100 ka), morphologic modeling (~0.06-0.21 mm/yr; 100 ka), and observations from the trench (~0.06-0.34 mm/yr; 15-75 ka) suggest that there has been no detectable change in slip rate in the past 1 million years or so." They document uncertainties for each group of measurements, suggesting that the range of values capture most or all of the epistemic and aleatory uncertainty in the data. We use the average of the eight end members (0.2 mm/yr) as our preferred slip rate. Dip of fault changed to 50? based on redefined regional default value (Lund, 2006).

Comments

Amoroso and others (2004) document a number of vertical slip rates using a variety of methods and datums for this part of the Hurricane fault. They state, "Slip-rate estimates using the Moriah Knoll basalt (~0.15-0.24 mm/yr; 850 ka), surface offset (~0.05-0.3 mm/yr; 100 ka), morphologic modeling (~0.06-0.21 mm/yr; 100 ka), and observations from the trench (~0.06-0.34 mm/yr; 15-75 ka) suggest that there has been no detectable change in slip rate in the past 1 million years or so." They document uncertainties for each group of measurements, suggesting that the range of values capture most or all of the epistemic and aleatory uncertainty in the data. We use the average of the eight end members (0.2 mm/yr) as our preferred slip rate. Dip of fault changed to 50? based on redefined regional default value (Lund, 2006).

Selected References
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. Amoroso, L., Pearthree, P.A., and Arrowsmith, J.R., 2004, Paleoseismology and neotectonics of the Shivwits section of the Hurricane fault, northwestern Arizona: Bulletin of the Seismological Society of America, v. 94, p. 1919-1942. 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

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.
Amoroso, L., Pearthree, P.A., and Arrowsmith, J.R., 2004, Paleoseismology and neotectonics of the Shivwits section of the Hurricane fault, northwestern Arizona: Bulletin of the Seismological Society of America, v. 94, p. 1919-1942.
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.