2008 National Seismic Hazard Maps - Fault Parameters

2007 National Seismic Hazard Maps-Fault parameters

Fault Name	State
Bear River fault zone	Wyoming

MODEL VALUES
Slip rate (vertical or horizontal in mm/yr)	1.5
Probability of activity	1

Minimum magnitude	6.5
Maximum magnitude	6.9

FAULT GEOMETRY
Dip (degrees)	50/60/40
Dip direction	W
Sense of slip	normal
Rupture top (km)	0
Rupture bottom (km)	15
Rake (degrees)	-90
Length (km)	37

Assigned Dip	Fault Parallel Slip Rate	Width	Characteristic Magnitude	Characteristic Rate	Weight
40	2.33	23.3	6.9	4.35E-04	0.2
50	1.96	19.6	6.9	4.35E-04	0.6
60	1.73	17.3	6.9	4.35E-04	0.2

Comments




Characteristic rate fixed to represent recurrence of 3 k.y. based on studies by West (1994). Assigned vertical slip rate of 1.5 mm/yr is consensus value reported by Lund (2005) based on original investigation by West (1994). Dip of fault changed to 50° based on redefined regional default value (Lund, 2006).
Selected References




West, M.W., 1994, Paleoseismology of Utah, volume 4--Seismotectonics of north-central Utah and southwestern Wyoming: Utah Geological Survey Special Study 82, 93 p., 5 pls. 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. 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.