Geodesy- and Geology-Based Slip-Rate Models for the Western United States (Excluding California) National Seismic Hazard Maps

The 2014 National Seismic Hazard Maps for the conterminous United States incorporate additional uncertainty in fault slip-rate parameter that controls the earthquake-activity rates than was applied in previous versions of the hazard maps. This additional uncertainty is accounted for by new geodesyand geology-based slip-rate models for the Western United States. Models that were considered include an updated geologic model based on expert opinion and four combined inversion models informed by both geologic and geodetic input. The two block models considered indicate significantly higher slip rates than the expert opinion and the two fault-based combined inversion models. For the hazard maps, we apply 20 percent weight with equal weighting for the two fault-based models. Off-fault geodetic-based models were not considered in this version of the maps. Resulting changes to the hazard maps are generally less than 0.05 g (acceleration of gravity). Future research will improve the maps and interpret differences between the new models.

[1]  M. Fritsche,et al.  Block modeling of crustal deformation in Tierra del Fuego from GNSS velocities , 2015 .

[2]  Robert W. King,et al.  Fault locking, block rotation and crustal deformation in the Pacific Northwest , 2007 .

[3]  J. C. Savage,et al.  Strain accumulation and rotation in the Eastern California Shear Zone , 2001 .

[4]  Robert McCaffrey,et al.  Crustal Block Rotations and Plate Coupling , 2013 .

[5]  É. Calais,et al.  Geodetic observations of interseismic strain segmentation at the Sumatra Subduction Zone , 1997 .

[6]  Richard G. Gordon,et al.  Geologically current plate motions , 2010 .

[7]  Robert W. King,et al.  A new interpretation of deformation rates in the Snake River Plain and adjacent basin and range regions based on GPS measurements , 2012 .

[8]  Brendan J. Meade,et al.  Block models of crustal motion in southern California constrained by GPS measurements , 2005 .

[9]  Egill Hauksson,et al.  Crustal structure and seismicity distribution adjacent to the Pacific and North America plate boundary in southern California , 2000 .

[10]  R. Bennett.  Instantaneous slip rates from geology and geodesy , 2007 .

[11]  Zheng‐Kang Shen,et al.  Fault network modeling of crustal deformation in California constrained using GPS and geologic observations , 2014 .

[12]  William Rodi,et al.  Global Positioning System constraints on fault slip rates in southern California and northern Baja, Mexico , 1996 .

[13]  W. Rucker.  Neotectonic Kinematic Analysis of Philippines Orogen: Regional Strain-Rates and a Forecast of Long-term Seismicity , 2008 .

[14]  G. Blewitt,et al.  Block modeling of crustal deformation of the northern Walker Lane and Basin and Range from GPS velocities , 2011 .

[15]  Robert McCaffrey,et al.  Block kinematics of the Pacific-North America plate boundary in the southwestern United States from inversion of GPS, seismological, and geologic data , 2005 .

[16]  Robert W. King,et al.  Present day kinematics of the Eastern California Shear Zone from a geodetically constrained block model , 2001 .

[17]  D. McKenzie,et al.  The North Pacific: an Example of Tectonics on a Sphere , 1967, Nature.

[18]  Duncan Carr Agnew,et al.  A unified analysis of crustal motion in Southern California, 1970–2004: The SCEC crustal motion map , 2011 .

[19]  W. Hammond,et al.  Crustal deformation across the Sierra Nevada, northern Walker Lane, Basin and Range transition, western United States measured with GPS, 2000–2004 , 2007 .

[20]  P. Bird,et al.  Exploratory models of long‐term crustal flow and resulting seismicity across the Alpine‐Aegean orogen , 2010 .

[21]  D. Jackson,et al.  Dislocation model for aseismic crustal deformation at Hollister, California , 1986 .

[22]  P. A. McCrory,et al.  Depth to the Juan De Fuca slab beneath the Cascadia subduction margin - a 3-D model for sorting earthquakes , 2004 .

[23]  J. C. Savage.  A dislocation model of strain accumulation and release at a subduction zone , 1983 .

[24]  G. Blewitt,et al.  Geodetic constraints on contemporary deformation in the northern Walker Lane: 3. Central Nevada seismic belt postseismic relaxation , 2009 .

[25]  G. Blewitt,et al.  Evidence for an active shear zone in southern Nevada linking the Wasatch fault to the Eastern California shear zone , 2010 .

[26]  Fred F. Pollitz,et al.  Mobility of continental mantle: Evidence from postseismic geodetic observations following the 1992 Landers earthquake , 2000 .

[27]  Ian Parsons,et al.  Surface deformation due to shear and tensile faults in a half-space , 1986 .

[28]  Hans-Peter Plag,et al.  Contemporary uplift of the Sierra Nevada, western United States, from GPS and InSAR measurements , 2012 .

[29]  Kaj M. Johnson,et al.  Reconciling geologic and geodetic model fault slip-rate discrepancies in Southern California: Consideration of nonsteady mantle flow and lower crustal fault creep , 2011 .

[30]  William A. Bryant,et al.  Probabilistic seismic hazard assessment for the state of California , 1996 .

[31]  Timothy E. Dawson,et al.  Geologic-Slip-Rate Data and Geologic Deformation Model , 2013 .

[32]  William C. Hammond,et al.  Contemporary tectonic deformation of the Basin and Range province, western United States: 10 years of observation with the Global Positioning System , 2004 .

[33]  R. King,et al.  Strain rates and contemporary deformation in the Snake River Plain and surrounding Basin and Range from GPS and seismicity , 2008 .

[34]  Takeshi Sagiya,et al.  A revised dislocation model of interseismic deformation of the Cascadia subduction zone , 2003 .

[35]  P. Segall,et al.  Modeling broadscale deformation in northern California and Nevada from plate motions and elastic strain accumulation , 2001 .

[36]  Robert W. King,et al.  Active tectonics of northwestern U.S. inferred from GPS‐derived surface velocities , 2013 .

[37]  Charles S. Mueller,et al.  Documentation for the 2008 update of the United States National Seismic Hazard Maps , 2008 .

[38]  J. C. Savage,et al.  Geodetic determination of relative plate motion in central California , 1973 .

[39]  David D. Jackson,et al.  Crustal deformation across and beyond the Los Angeles basin from geodetic measurements , 1996 .

[40]  R. Weldon,et al.  Interseismic uplift rates for western Oregon and along‐strike variation in locking on the Cascadia subduction zone , 2009 .

[41]  Y. Okada.  Internal deformation due to shear and tensile faults in a half-space , 1992, Bulletin of the Seismological Society of America.

[42]  James L. Davis,et al.  Comparison of geodetic and geologic data from the Wasatch region, Utah, and implications for the spectral character of Earth deformation at periods of 10 to 10 million years , 2003 .

[43]  Kelin Wang,et al.  Three‐dimensional dislocation model for great earthquakes of the Cascadia Subduction Zone , 1997 .