2008 National Seismic Hazard Maps

2008 National Seismic Hazard Maps-Fault parameters

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Fault Name	State
Klamath graben fault system (east)	Oregon

GEOMETRY
Dip (degrees)	50
Dip direction	W
Sense of slip	normal
Rupture top (km)	0
Rupture bottom (km)	15
Rake (degrees)	-90
Length (km)	92

MODEL VALUES
Probability of activity	1
Minimum magnitude	6.5
Maximum magnitude	7.36
b-value	0.8

Assigned Dip	Fault-Parallel Slip Rate	Width	Annual Rate	a-value
50	0.26	19.6	1.15e-04	1.313

Comments
The 1996 East Klamath graben fault and, on strike to the south, the 1996 South Klamath graben zone form the eastern edge of the Klamath graben. Geomatrix Consultants, Inc. (1995) provides a three-point probability distribution of slip rate: 0.15 mm/yr (probability 0.4), 0.2 mm/yr (0.5), and 0.5 mm/yr (0.1). The age-offset data cited by Geomatrix Consultants, Inc. (1995) are either from pre-Quaternary surfaces, which provide very slow slip rates, or from a potentially single-rupture scarp on a mid-Holocene ash, which provides no constraint. The assigned vertical slip rate is the highest probability rate (0.2 mm/yr) in the three-point distribution of Geomatrix Consultants, Inc. (1995). Dip of fault changed to 50? based on redefined regional default value (Lund, 2006).

Comments

The 1996 East Klamath graben fault and, on strike to the south, the 1996 South Klamath graben zone form the eastern edge of the Klamath graben. Geomatrix Consultants, Inc. (1995) provides a three-point probability distribution of slip rate: 0.15 mm/yr (probability 0.4), 0.2 mm/yr (0.5), and 0.5 mm/yr (0.1). The age-offset data cited by Geomatrix Consultants, Inc. (1995) are either from pre-Quaternary surfaces, which provide very slow slip rates, or from a potentially single-rupture scarp on a mid-Holocene ash, which provides no constraint. The assigned vertical slip rate is the highest probability rate (0.2 mm/yr) in the three-point distribution of Geomatrix Consultants, Inc. (1995). Dip of fault changed to 50? based on redefined regional default value (Lund, 2006).

Selected References
Geomatrix Consultants, Inc., 1995, Seismic design mapping, State of Oregon: Technical report to Oregon Department of Transportation, Salem, Oregon, under Contract 11688, January 1995, unpaginated, 5 pls., scale 1:1,250,000. 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

Geomatrix Consultants, Inc., 1995, Seismic design mapping, State of Oregon: Technical report to Oregon Department of Transportation, Salem, Oregon, under Contract 11688, January 1995, unpaginated, 5 pls., scale 1:1,250,000.
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.