Robert W Graves
Rob Graves is a geophysicist in the Earthquake Hazards Program.
Science and Products
Filter Total Items: 65
Evidence for strong lateral seismic velocity variation in the lower crust and upper mantle beneath the California margin Evidence for strong lateral seismic velocity variation in the lower crust and upper mantle beneath the California margin
Regional seismograms from earthquakes in Northern California show a systematic difference in arrival times across Southern California where long period (30–50 seconds) SH waves arrive up to 15 seconds earlier at stations near the coast compared with sites towards the east at similar epicentral distances. We attribute this time difference to heterogeneity of the velocity structure at the...
Authors
Voon Lai, Robert Graves, Shengji Wei, Don Helmberger
Kinematic ground motion simulations on rough faults including effects of 3D stochastic velocity perturbations Kinematic ground motion simulations on rough faults including effects of 3D stochastic velocity perturbations
We describe a methodology for generating kinematic earthquake ruptures for use in 3D ground‐motion simulations over the 0–5 Hz frequency band. Our approach begins by specifying a spatially random slip distribution that has a roughly wavenumber‐squared fall‐off. Given a hypocenter, the rupture speed is specified to average about 75%–80% of the local shear wavespeed and the prescribed slip...
Authors
Robert Graves, Arben Pitarka
Refinements to the Graves and Pitarka (2010) Broadband Ground Motion Simulation Method Refinements to the Graves and Pitarka (2010) Broadband Ground Motion Simulation Method
This brief article describes refinements to the Graves and Pitarka (2010) broadband ground motion simulation methodology (GP2010 hereafter) that have been implemented in version 14.3 of the SCEC Broadband Platform (BBP). The updated version of our method on the current SCEC BBP is referred to as GP14.3. Our simulation technique is a hybrid approach that combines low-‐frequency and high-...
Authors
Robert Graves, Arben Pitarka
Ground motion-simulations of 1811-1812 New Madrid earthquakes, central United States Ground motion-simulations of 1811-1812 New Madrid earthquakes, central United States
We performed a suite of numerical simulations based on the 1811–1812 New Madrid seismic zone (NMSZ) earthquakes, which demonstrate the importance of 3D geologic structure and rupture directivity on the ground‐motion response throughout a broad region of the central United States (CUS) for these events. Our simulation set consists of 20 hypothetical earthquakes located along two faults...
Authors
L. Ramirez-Guzman, Robert Graves, Kim Olsen, Oliver S. Boyd, Chris H. Cramer, Stephen H. Hartzell, Sidao Ni, Paul G. Somerville, Robert Williams, Jinquan Zhong
The 2014 Mw6.1 South Napa Earthquake: A unilateral rupture with shallow asperity and rapid afterslip The 2014 Mw6.1 South Napa Earthquake: A unilateral rupture with shallow asperity and rapid afterslip
The Mw6.1 South Napa earthquake occurred near Napa, California on August 24, 2014 (UTC), and was the largest inland earthquake in Northern California since the 1989 Mw6.9 Loma Prieta earthquake. The first report of the earthquake from the Northern California Earthquake Data Center (NCEDC) indicates a hypocentral depth of 11.0km with longitude and latitude of (122.3105°W, 38.217°N)...
Authors
Shengji Wei, Sylvain Barbot, Robert Graves, James J. Lienkaemper, Teng Wang, Kenneth W. Hudnut, Yuning Fu, Don Helmberger
NGA-West2 Research Project NGA-West2 Research Project
The NGA-West2 project is a large multidisciplinary, multi-year research program on the Next Generation Attenuation (NGA) models for shallow crustal earthquakes in active tectonic regions. The research project has been coordinated by the Pacific Earthquake Engineering Research Center (PEER), with extensive technical interactions among many individuals and organizations. NGA-West2...
Authors
Yousef Bozorgnia, Norman A. Abrahamson, Linda Al Atik, Timothy D. Ancheta, Gail M. Atkinson, Jack W. Baker, Annemarie S. Baltay Sundstrom, David M. Boore, Kenneth W. Campbell, Brian S.J. Chiou, Robert B. Darragh, Steve Day, Jennifer Donahue, Robert W. Graves, Nick Gregor, Thomas C. Hanks, I. M. Idriss, Ronnie Kamai, Tadahiro Kishida, Albert Kottke, Stephen A. Mahin, Sanaz Rezaeian, Badie Rowshandel, Emel Seyhan, Shrey Shahi, Tom Shantz, Walter Silva, Paul A. Spudich, Jonathan P. Stewart, Jennie Watson-Lamprey, Kathryn Wooddell, Robert Youngs
Science and Products
Filter Total Items: 65
Evidence for strong lateral seismic velocity variation in the lower crust and upper mantle beneath the California margin Evidence for strong lateral seismic velocity variation in the lower crust and upper mantle beneath the California margin
Regional seismograms from earthquakes in Northern California show a systematic difference in arrival times across Southern California where long period (30–50 seconds) SH waves arrive up to 15 seconds earlier at stations near the coast compared with sites towards the east at similar epicentral distances. We attribute this time difference to heterogeneity of the velocity structure at the...
Authors
Voon Lai, Robert Graves, Shengji Wei, Don Helmberger
Kinematic ground motion simulations on rough faults including effects of 3D stochastic velocity perturbations Kinematic ground motion simulations on rough faults including effects of 3D stochastic velocity perturbations
We describe a methodology for generating kinematic earthquake ruptures for use in 3D ground‐motion simulations over the 0–5 Hz frequency band. Our approach begins by specifying a spatially random slip distribution that has a roughly wavenumber‐squared fall‐off. Given a hypocenter, the rupture speed is specified to average about 75%–80% of the local shear wavespeed and the prescribed slip...
Authors
Robert Graves, Arben Pitarka
Refinements to the Graves and Pitarka (2010) Broadband Ground Motion Simulation Method Refinements to the Graves and Pitarka (2010) Broadband Ground Motion Simulation Method
This brief article describes refinements to the Graves and Pitarka (2010) broadband ground motion simulation methodology (GP2010 hereafter) that have been implemented in version 14.3 of the SCEC Broadband Platform (BBP). The updated version of our method on the current SCEC BBP is referred to as GP14.3. Our simulation technique is a hybrid approach that combines low-‐frequency and high-...
Authors
Robert Graves, Arben Pitarka
Ground motion-simulations of 1811-1812 New Madrid earthquakes, central United States Ground motion-simulations of 1811-1812 New Madrid earthquakes, central United States
We performed a suite of numerical simulations based on the 1811–1812 New Madrid seismic zone (NMSZ) earthquakes, which demonstrate the importance of 3D geologic structure and rupture directivity on the ground‐motion response throughout a broad region of the central United States (CUS) for these events. Our simulation set consists of 20 hypothetical earthquakes located along two faults...
Authors
L. Ramirez-Guzman, Robert Graves, Kim Olsen, Oliver S. Boyd, Chris H. Cramer, Stephen H. Hartzell, Sidao Ni, Paul G. Somerville, Robert Williams, Jinquan Zhong
The 2014 Mw6.1 South Napa Earthquake: A unilateral rupture with shallow asperity and rapid afterslip The 2014 Mw6.1 South Napa Earthquake: A unilateral rupture with shallow asperity and rapid afterslip
The Mw6.1 South Napa earthquake occurred near Napa, California on August 24, 2014 (UTC), and was the largest inland earthquake in Northern California since the 1989 Mw6.9 Loma Prieta earthquake. The first report of the earthquake from the Northern California Earthquake Data Center (NCEDC) indicates a hypocentral depth of 11.0km with longitude and latitude of (122.3105°W, 38.217°N)...
Authors
Shengji Wei, Sylvain Barbot, Robert Graves, James J. Lienkaemper, Teng Wang, Kenneth W. Hudnut, Yuning Fu, Don Helmberger
NGA-West2 Research Project NGA-West2 Research Project
The NGA-West2 project is a large multidisciplinary, multi-year research program on the Next Generation Attenuation (NGA) models for shallow crustal earthquakes in active tectonic regions. The research project has been coordinated by the Pacific Earthquake Engineering Research Center (PEER), with extensive technical interactions among many individuals and organizations. NGA-West2...
Authors
Yousef Bozorgnia, Norman A. Abrahamson, Linda Al Atik, Timothy D. Ancheta, Gail M. Atkinson, Jack W. Baker, Annemarie S. Baltay Sundstrom, David M. Boore, Kenneth W. Campbell, Brian S.J. Chiou, Robert B. Darragh, Steve Day, Jennifer Donahue, Robert W. Graves, Nick Gregor, Thomas C. Hanks, I. M. Idriss, Ronnie Kamai, Tadahiro Kishida, Albert Kottke, Stephen A. Mahin, Sanaz Rezaeian, Badie Rowshandel, Emel Seyhan, Shrey Shahi, Tom Shantz, Walter Silva, Paul A. Spudich, Jonathan P. Stewart, Jennie Watson-Lamprey, Kathryn Wooddell, Robert Youngs