William J Stephenson
Bill Stephensen is a scientist in the Earthquake Hazards Program.
Science and Products
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Paleoseismic results from the Alpine site, Wasatch fault zone: Timing and displacement data for six holocene earthquakes at the Salt Lake City–Provo segment boundary Paleoseismic results from the Alpine site, Wasatch fault zone: Timing and displacement data for six holocene earthquakes at the Salt Lake City–Provo segment boundary
To improve the characterization of Holocene earthquakes on the Wasatch fault zone (WFZ), we conducted light detection and ranging (lidar)‐based neotectonic mapping and excavated a paleoseismic trench across an 8‐m‐high fault scarp near Alpine, Utah, located ∼6.2–0.4 ka∼6.2–0.4 ka. Interseismic recurrence ranges from 0.2 to 1.8 ky (mean 1.2 ky). We estimate 6.5±0.7 m6.5±0.7 m of...
Authors
Scott Bennett, Christopher DuRoss, Ryan Gold, Richard Briggs, Stephen Personius, Nadine Reitman, Joshua Devore, Adam Hiscock, Shannon Mahan, Harrison J. Gray, Sydney Gunnarson, William Stephenson, Elizabeth Pettinger, Jackson K. Odum
Holocene fault reactivation in the eastern Cascades, Washington Holocene fault reactivation in the eastern Cascades, Washington
Significant uncertainty remains concerning how and where crustal shortening occurs throughout the eastern Cascade Range in Washington State. Using light detection and ranging (lidar) imagery, we identified an ∼5‐km‐long lineament in Swakane canyon near Wenatchee, roughly coincident with a strand of the Entiat fault. Topographic profiles across the lineament reveal a southwest‐side‐up...
Authors
Benjamin Carlson, Elizabeth Schermer, Colin Amos, William Stephenson, Brian Sherrod, Shannon Mahan
Broadband synthetic seismograms for magnitude 9 earthquakes on the Cascadia megathrust based on 3D simulations and stochastic synthetics, part 1: Methodology and overall results Broadband synthetic seismograms for magnitude 9 earthquakes on the Cascadia megathrust based on 3D simulations and stochastic synthetics, part 1: Methodology and overall results
We have produced a large set of broadband (0–10 Hz) synthetic seismograms for Mw 9.0 earthquakes on the Cascadia megathrust by combining synthetic seismograms derived from 3D finite‐difference simulations (≤1 Hz) with finite‐source, stochastic synthetics (≥1 Hz). We used a compound rupture model consisting of high stress drop Mw 8 subevents superimposed on large, shallower slip...
Authors
Arthur Frankel, Erin Wirth, Nasser Marafi, John Vidale, William Stephenson
Broadband synthetic seismograms for magnitude 9 earthquakes on the Cascadia Megathrust based on 3D simulations and stochastic synthetics, Part 2: Rupture parameters and variability Broadband synthetic seismograms for magnitude 9 earthquakes on the Cascadia Megathrust based on 3D simulations and stochastic synthetics, Part 2: Rupture parameters and variability
We used a combination of 3D finite‐difference simulations (>1 Hz) to generate broadband (0–10 Hz) synthetic seismograms for numerous Mw 9 earthquake rupture scenarios on the Cascadia megathrust. Slip consists of multiple high‐stress‐drop subevents (Mw 8) with short rise times on the deeper portions of the fault, superimposed on a background slip distribution with longer rise times. We...
Authors
Erin Wirth, Arthur Frankel, Nasser Marafi, John Vidale, William Stephenson
Integrate urban‐scale seismic hazard analyses with the U.S. National Seismic Hazard Model Integrate urban‐scale seismic hazard analyses with the U.S. National Seismic Hazard Model
For more than 20 yrs, damage patterns and instrumental recordings have highlighted the influence of the local 3D geologic structure on earthquake ground motions (e.g., MM 6.7 Northridge, California, Gao et al., 1996; MM 6.9 Kobe, Japan, Kawase, 1996; MM 6.8 Nisqually, Washington, Frankel, Carver, and Williams, 2002). Although this and other local‐scale features are critical to improving...
Authors
Morgan Moschetti, Nico Luco, Arthur Frankel, Mark Petersen, Brad Aagaard, Annemarie Baltay Sundstrom, Michael Blanpied, Oliver Boyd, Richard Briggs, Ryan Gold, Robert Graves, Stephen Hartzell, Sanaz Rezaeian, William Stephenson, David Wald, Robert A. Williams, Kyle Withers
P- and S-wave velocity models incorporating the Cascadia subduction zone for 3D earthquake ground motion simulations, Version 1.6—Update for Open-File Report 2007–1348 P- and S-wave velocity models incorporating the Cascadia subduction zone for 3D earthquake ground motion simulations, Version 1.6—Update for Open-File Report 2007–1348
In support of earthquake hazard studies and ground motion simulations in the Pacific Northwest, three-dimensional P- and S-wave velocity (VP and VS, respectively) models incorporating the Cascadia subduction zone were previously developed for the region encompassed from about 40.2°N. to 50°N. latitude, and from about 122°W. to 129°W. longitude. This report describes updates to the...
Authors
William Stephenson, Nadine Reitman, Stephen Angster
Science and Products
Filter Total Items: 15
No Result Found
Filter Total Items: 63
Paleoseismic results from the Alpine site, Wasatch fault zone: Timing and displacement data for six holocene earthquakes at the Salt Lake City–Provo segment boundary Paleoseismic results from the Alpine site, Wasatch fault zone: Timing and displacement data for six holocene earthquakes at the Salt Lake City–Provo segment boundary
To improve the characterization of Holocene earthquakes on the Wasatch fault zone (WFZ), we conducted light detection and ranging (lidar)‐based neotectonic mapping and excavated a paleoseismic trench across an 8‐m‐high fault scarp near Alpine, Utah, located ∼6.2–0.4 ka∼6.2–0.4 ka. Interseismic recurrence ranges from 0.2 to 1.8 ky (mean 1.2 ky). We estimate 6.5±0.7 m6.5±0.7 m of...
Authors
Scott Bennett, Christopher DuRoss, Ryan Gold, Richard Briggs, Stephen Personius, Nadine Reitman, Joshua Devore, Adam Hiscock, Shannon Mahan, Harrison J. Gray, Sydney Gunnarson, William Stephenson, Elizabeth Pettinger, Jackson K. Odum
Holocene fault reactivation in the eastern Cascades, Washington Holocene fault reactivation in the eastern Cascades, Washington
Significant uncertainty remains concerning how and where crustal shortening occurs throughout the eastern Cascade Range in Washington State. Using light detection and ranging (lidar) imagery, we identified an ∼5‐km‐long lineament in Swakane canyon near Wenatchee, roughly coincident with a strand of the Entiat fault. Topographic profiles across the lineament reveal a southwest‐side‐up...
Authors
Benjamin Carlson, Elizabeth Schermer, Colin Amos, William Stephenson, Brian Sherrod, Shannon Mahan
Broadband synthetic seismograms for magnitude 9 earthquakes on the Cascadia megathrust based on 3D simulations and stochastic synthetics, part 1: Methodology and overall results Broadband synthetic seismograms for magnitude 9 earthquakes on the Cascadia megathrust based on 3D simulations and stochastic synthetics, part 1: Methodology and overall results
We have produced a large set of broadband (0–10 Hz) synthetic seismograms for Mw 9.0 earthquakes on the Cascadia megathrust by combining synthetic seismograms derived from 3D finite‐difference simulations (≤1 Hz) with finite‐source, stochastic synthetics (≥1 Hz). We used a compound rupture model consisting of high stress drop Mw 8 subevents superimposed on large, shallower slip...
Authors
Arthur Frankel, Erin Wirth, Nasser Marafi, John Vidale, William Stephenson
Broadband synthetic seismograms for magnitude 9 earthquakes on the Cascadia Megathrust based on 3D simulations and stochastic synthetics, Part 2: Rupture parameters and variability Broadband synthetic seismograms for magnitude 9 earthquakes on the Cascadia Megathrust based on 3D simulations and stochastic synthetics, Part 2: Rupture parameters and variability
We used a combination of 3D finite‐difference simulations (>1 Hz) to generate broadband (0–10 Hz) synthetic seismograms for numerous Mw 9 earthquake rupture scenarios on the Cascadia megathrust. Slip consists of multiple high‐stress‐drop subevents (Mw 8) with short rise times on the deeper portions of the fault, superimposed on a background slip distribution with longer rise times. We...
Authors
Erin Wirth, Arthur Frankel, Nasser Marafi, John Vidale, William Stephenson
Integrate urban‐scale seismic hazard analyses with the U.S. National Seismic Hazard Model Integrate urban‐scale seismic hazard analyses with the U.S. National Seismic Hazard Model
For more than 20 yrs, damage patterns and instrumental recordings have highlighted the influence of the local 3D geologic structure on earthquake ground motions (e.g., MM 6.7 Northridge, California, Gao et al., 1996; MM 6.9 Kobe, Japan, Kawase, 1996; MM 6.8 Nisqually, Washington, Frankel, Carver, and Williams, 2002). Although this and other local‐scale features are critical to improving...
Authors
Morgan Moschetti, Nico Luco, Arthur Frankel, Mark Petersen, Brad Aagaard, Annemarie Baltay Sundstrom, Michael Blanpied, Oliver Boyd, Richard Briggs, Ryan Gold, Robert Graves, Stephen Hartzell, Sanaz Rezaeian, William Stephenson, David Wald, Robert A. Williams, Kyle Withers
P- and S-wave velocity models incorporating the Cascadia subduction zone for 3D earthquake ground motion simulations, Version 1.6—Update for Open-File Report 2007–1348 P- and S-wave velocity models incorporating the Cascadia subduction zone for 3D earthquake ground motion simulations, Version 1.6—Update for Open-File Report 2007–1348
In support of earthquake hazard studies and ground motion simulations in the Pacific Northwest, three-dimensional P- and S-wave velocity (VP and VS, respectively) models incorporating the Cascadia subduction zone were previously developed for the region encompassed from about 40.2°N. to 50°N. latitude, and from about 122°W. to 129°W. longitude. This report describes updates to the...
Authors
William Stephenson, Nadine Reitman, Stephen Angster