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William J Stephenson

Bill Stephensen is a scientist in the Earthquake Hazards Program.

Science and Products

Image Collage of Landsat, pollinator, and volcanologist

Crustal Characterization

The geophysical structure of the Earth’s crust, from the surface to the Moho, plays a major role in seismic hazard by influencing earthquake source properties and wave propagation from the earthquake to the Earth’s surface. We make field measurements and create models to better characterize the crust and resulting earthquake ground motions.
By
Natural Hazards Mission Area, Earthquake Hazards Program
Crustal Characterization

Crustal Characterization

The geophysical structure of the Earth’s crust, from the surface to the Moho, plays a major role in seismic hazard by influencing earthquake source properties and wave propagation from the earthquake to the Earth’s surface. We make field measurements and create models to better characterize the crust and resulting earthquake ground motions.
Learn More
Trona Wildrose Road in the Panamint Valley, California, along the section of the seismic reflection survey, looking west.

Untangling Faults at Depth – What Lies Beneath Panamint Valley, California?

Release Date: APRIL 30, 2018 The eastern edge of Panamint Valley,CA has two types of faults that can be seen in the near-surface geology. 150 geophones and a seismic source will help reveal the subsurface picture.
By
Natural Hazards Mission Area, Earthquake Hazards Program
Untangling Faults at Depth – What Lies Beneath Panamint Valley, California?

Untangling Faults at Depth – What Lies Beneath Panamint Valley, California?

Release Date: APRIL 30, 2018 The eastern edge of Panamint Valley,CA has two types of faults that can be seen in the near-surface geology. 150 geophones and a seismic source will help reveal the subsurface picture.
Learn More
Temporary seismometer array in New York City to record ambient noise.

Seismology in the City

Release Date: May 1, 2015 How seismologists can use noise to see under the ground.
By
Natural Hazards Mission Area, Earthquake Hazards Program
Seismology in the City

Seismology in the City

Release Date: May 1, 2015 How seismologists can use noise to see under the ground.
Learn More
Filter Total Items: 15

Seismic reflection data imaging the Meadow Bank scarp in the Wabash Valley Seismic Zone, southeastern Illinois, U.S. Geological Survey data release Seismic reflection data imaging the Meadow Bank scarp in the Wabash Valley Seismic Zone, southeastern Illinois, U.S. Geological Survey data release

The U.S. Geological Survey, in collaboration with seismologists from University of Kentucky, performed a 917-meter east-west oriented shear horizontal (SH)-wave seismic-reflection survey in the Wabash Valley Seismic Zone in southeastern Illinois. The resulting profile, named ML-2, images the near-surface geology underlying the Meadow Bank scarp, a roughly 10-km long northeast-oriented...
By
Geologic Hazards Science Center

Data for A 3-D Seismic Velocity Model for Cascadia with Shallow Soils & Topography, Version 1.7 Data for A 3-D Seismic Velocity Model for Cascadia with Shallow Soils & Topography, Version 1.7

This data release contains three netCDF4 files containing grid points of P- and S-wave seismic velocities in Cascadia. This model is an update to Stephenson et al. (2017) Open-File Report 2017-1152, and contains a newly added shallow soil model and optional user-specified topography. A description of the model and its development is provided in the associated Open-File Report. The grid...
By
Earthquake Hazards Program

Shear-wave velocity surface seismic site characterization data at 21 sites in Puerto Rico Shear-wave velocity surface seismic site characterization data at 21 sites in Puerto Rico

In collaboration with researchers at the University of Puerto Rico, Mayaguez, the U.S. Geological Survey acquired multimethod surface seismic imaging data at 21 sites in Puerto Rico for shear-wave velocity site characterization. These data were collected at both permanent and temporary seismograph stations throughout the island, between March 6 and March 18, 2022. Data were acquired...
By
Geologic Hazards Science Center

Microtremor array data on Whidbey Island, Washington Microtremor array data on Whidbey Island, Washington

The U.S. Geological Survey collected a grid of microtremor data points using Smartsolo 3-component seismic sensors from August 7th to August 11th, 2023. These sensors have a five Hz resonance frequency. The grid was deployed over a section of the Utsalady Point fault that runs east-west across the southern portion of the Naval Air Station Whidbey Island, Washington State. For four days...
By
Geologic Hazards Science Center

Seismic Reflection Profiles Imaging the Seattle Fault Zone Beneath West Seattle, Central Seattle, and Mercer Island, Washington State Seismic Reflection Profiles Imaging the Seattle Fault Zone Beneath West Seattle, Central Seattle, and Mercer Island, Washington State

The U.S. Geological Survey, with funding from the National Earthquakes Hazard Reduction Program, collected ~24 km of north-south trending land-based P-wave seismic reflection profiles gathered across three urban areas in Seattle, Washington: West Seattle, central Seattle, and Mercer Island. The West Seattle profiles were collected with an accelerated weight drop source and 8 Hz vertical...
By
Natural Hazards Mission Area, Earthquake Hazards Program, Geologic Hazards Science Center

Miscellaneous Microtremor Array Datasets from the Puget Lowland, Washington State Miscellaneous Microtremor Array Datasets from the Puget Lowland, Washington State

Abstract: We compile three microtremor array datasets acquired in three campaigns in the Seattle and Tacoma basins, Washington State. These datasets were acquired between 2007 and 2018. Dataset 1 includes seven sites in the western Seattle and Tacoma basins acquired to image shear-wave velocity (Vs) in the upper 1 km that are suitable for analysis with microtremor methods not requiring...
By
Geologic Hazards Science Center
Filter Total Items: 63

Three-dimensional seismic velocity model for the Cascadia Subduction Zone with shallow soils and topography, version 1.7 Three-dimensional seismic velocity model for the Cascadia Subduction Zone with shallow soils and topography, version 1.7

The U.S. Geological Survey’s seismic velocity model for the Cascadia Subduction Zone provides P- and S-wave velocity (VP and VS, respectively) information from 40.2° to 50.0° N. latitude and −129.0° to −121.0° W. longitude, and is used to support a variety of research topics, including three-dimensional (3D) earthquake simulations and seismic hazard assessment in the Pacific Northwest...
Authors
Erin Wirth, Alex Grant, Ian Stone, William Stephenson, Arthur Frankel
By
Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center

Shallow faulting and folding beneath south‐central Seattle, Washington State, from land‐based high‐resolution seismic‐reflection imaging Shallow faulting and folding beneath south‐central Seattle, Washington State, from land‐based high‐resolution seismic‐reflection imaging

The geologic framework of the Seattle fault zone (SFZ) has been extensively studied, but the structure and fault strand locations in the central portion of the fault zone through the city of Seattle have remained controversial. Much of what is known about the SFZ has come from light detection and ranging (lidar)‐topographic surveys and paleoseismic investigations of fault scarps...
Authors
William Stephenson, Jack Odum, Thomas Pratt
By
Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center, Geologic Hazards Science Center

Empirical ground-motion basin response in the California Great Valley, Reno, Nevada, and Portland, Oregon Empirical ground-motion basin response in the California Great Valley, Reno, Nevada, and Portland, Oregon

We assess how well the Next-Generation Attenuation-West 2 (NGA-West2) ground-motion models (GMMs), which are used in the US Geological Survey’s (USGS) National Seismic Hazard Model (NSHM) for crustal faults in the western United States, predict the observed basin response in the Great Valley of California, the Reno basin in Nevada, and Portland and Tualatin basins in Oregon. These GMMs...
Authors
Sean Ahdi, Brad Aagaard, Morgan Moschetti, Grace Parker, Oliver Boyd, William Stephenson
By
Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center, Geologic Hazards Science Center

The 2023 US National Seismic Hazard Model: Ground-motion characterization for the conterminous United States The 2023 US National Seismic Hazard Model: Ground-motion characterization for the conterminous United States

We update the ground-motion characterization for the 2023 National Seismic Hazard Model (NSHM) for the conterminous United States. The update includes the use of new ground-motion models (GMMs) in the Cascadia subduction zone; an adjustment to the central and eastern United States (CEUS) GMMs to reduce misfits with observed data; an updated boundary for the application of GMMs for...
Authors
Morgan Moschetti, Brad Aagaard, Sean Ahdi, Jason Altekruse, Oliver Boyd, Arthur Frankel, Julie Herrick, Mark Petersen, Peter Powers, Sanaz Rezaeian, Allison Shumway, James Smith, William Stephenson, Eric Thompson, Kyle Withers
By
Geologic Hazards Science Center

The 2023 US 50-State National Seismic Hazard Model: Overview and implications The 2023 US 50-State National Seismic Hazard Model: Overview and implications

The US National Seismic Hazard Model (NSHM) was updated in 2023 for all 50 states using new science on seismicity, fault ruptures, ground motions, and probabilistic techniques to produce a standard of practice for public policy and other engineering applications (defined for return periods greater than ∼475 or less than ∼10,000 years). Changes in 2023 time-independent seismic hazard...
Authors
Mark Petersen, Allison Shumway, Peter Powers, Edward Field, Morgan Moschetti, Kishor Jaiswal, Kevin Milner, Sanaz Rezaeian, Arthur Frankel, Andrea Llenos, Andrew Michael, Jason Altekruse, Sean Ahdi, Kyle Withers, Charles Mueller, Yuehua Zeng, Robert Chase, Leah Salditch, Nico Luco, Kenneth S. Rukstales, Julie Herrick, Demi Girot, Brad Aagaard, Adrian Bender, Michael Blanpied, Richard Briggs, Oliver Boyd, Brandon Clayton, Christopher DuRoss, Eileen L. Evans, Peter J. Haeussler, Alexandra Hatem, Kirstie Haynie, Elizabeth Hearn, Kaj Johnson, Zachary Kortum, N. Kwong, Andrew Makdisi, Henry Mason, Daniel McNamara, Devin McPhillips, P. Okubo, Morgan Page, Frederick Pollitz, Justin Rubinstein, Bruce Shaw, Zheng-Kang Shen, Brian Shiro, James Smith, William Stephenson, Eric Thompson, Jessica Jobe, Erin Wirth, Robert C. Witter
By
Natural Hazards Mission Area, Earthquake Hazards Program, Geologic Hazards Science Center, Supplemental Appropriations for Disaster Recovery Activities

Implementation of basin models and sediment depth terms in the 2023 update of the U.S. National Seismic Hazard Model: Example from Reno, Nevada Implementation of basin models and sediment depth terms in the 2023 update of the U.S. National Seismic Hazard Model: Example from Reno, Nevada

We present a framework to evaluate the inclusion of candidate basin depth models in the U.S. Geological Survey National Seismic Hazard Model. We compute intensity measures (peak and spectral amplitudes) from uniformly processed earthquake ground motions in and around the basin of interest and compare these to ground-motion model (GMM) estimates over a range of oscillator periods. The...
Authors
Sean Ahdi, Morgan Moschetti, Brad Aagaard, Kaitlyn Abernathy, Oliver Boyd, William Stephenson
By
Natural Hazards Mission Area, Geologic Hazards Science Center

Science and Products

Image Collage of Landsat, pollinator, and volcanologist

Crustal Characterization

The geophysical structure of the Earth’s crust, from the surface to the Moho, plays a major role in seismic hazard by influencing earthquake source properties and wave propagation from the earthquake to the Earth’s surface. We make field measurements and create models to better characterize the crust and resulting earthquake ground motions.
By
Natural Hazards Mission Area, Earthquake Hazards Program
Crustal Characterization

Crustal Characterization

The geophysical structure of the Earth’s crust, from the surface to the Moho, plays a major role in seismic hazard by influencing earthquake source properties and wave propagation from the earthquake to the Earth’s surface. We make field measurements and create models to better characterize the crust and resulting earthquake ground motions.
Learn More
Trona Wildrose Road in the Panamint Valley, California, along the section of the seismic reflection survey, looking west.

Untangling Faults at Depth – What Lies Beneath Panamint Valley, California?

Release Date: APRIL 30, 2018 The eastern edge of Panamint Valley,CA has two types of faults that can be seen in the near-surface geology. 150 geophones and a seismic source will help reveal the subsurface picture.
By
Natural Hazards Mission Area, Earthquake Hazards Program
Untangling Faults at Depth – What Lies Beneath Panamint Valley, California?

Untangling Faults at Depth – What Lies Beneath Panamint Valley, California?

Release Date: APRIL 30, 2018 The eastern edge of Panamint Valley,CA has two types of faults that can be seen in the near-surface geology. 150 geophones and a seismic source will help reveal the subsurface picture.
Learn More
Temporary seismometer array in New York City to record ambient noise.

Seismology in the City

Release Date: May 1, 2015 How seismologists can use noise to see under the ground.
By
Natural Hazards Mission Area, Earthquake Hazards Program
Seismology in the City

Seismology in the City

Release Date: May 1, 2015 How seismologists can use noise to see under the ground.
Learn More
Filter Total Items: 15

Seismic reflection data imaging the Meadow Bank scarp in the Wabash Valley Seismic Zone, southeastern Illinois, U.S. Geological Survey data release Seismic reflection data imaging the Meadow Bank scarp in the Wabash Valley Seismic Zone, southeastern Illinois, U.S. Geological Survey data release

The U.S. Geological Survey, in collaboration with seismologists from University of Kentucky, performed a 917-meter east-west oriented shear horizontal (SH)-wave seismic-reflection survey in the Wabash Valley Seismic Zone in southeastern Illinois. The resulting profile, named ML-2, images the near-surface geology underlying the Meadow Bank scarp, a roughly 10-km long northeast-oriented...
By
Geologic Hazards Science Center

Data for A 3-D Seismic Velocity Model for Cascadia with Shallow Soils & Topography, Version 1.7 Data for A 3-D Seismic Velocity Model for Cascadia with Shallow Soils & Topography, Version 1.7

This data release contains three netCDF4 files containing grid points of P- and S-wave seismic velocities in Cascadia. This model is an update to Stephenson et al. (2017) Open-File Report 2017-1152, and contains a newly added shallow soil model and optional user-specified topography. A description of the model and its development is provided in the associated Open-File Report. The grid...
By
Earthquake Hazards Program

Shear-wave velocity surface seismic site characterization data at 21 sites in Puerto Rico Shear-wave velocity surface seismic site characterization data at 21 sites in Puerto Rico

In collaboration with researchers at the University of Puerto Rico, Mayaguez, the U.S. Geological Survey acquired multimethod surface seismic imaging data at 21 sites in Puerto Rico for shear-wave velocity site characterization. These data were collected at both permanent and temporary seismograph stations throughout the island, between March 6 and March 18, 2022. Data were acquired...
By
Geologic Hazards Science Center

Microtremor array data on Whidbey Island, Washington Microtremor array data on Whidbey Island, Washington

The U.S. Geological Survey collected a grid of microtremor data points using Smartsolo 3-component seismic sensors from August 7th to August 11th, 2023. These sensors have a five Hz resonance frequency. The grid was deployed over a section of the Utsalady Point fault that runs east-west across the southern portion of the Naval Air Station Whidbey Island, Washington State. For four days...
By
Geologic Hazards Science Center

Seismic Reflection Profiles Imaging the Seattle Fault Zone Beneath West Seattle, Central Seattle, and Mercer Island, Washington State Seismic Reflection Profiles Imaging the Seattle Fault Zone Beneath West Seattle, Central Seattle, and Mercer Island, Washington State

The U.S. Geological Survey, with funding from the National Earthquakes Hazard Reduction Program, collected ~24 km of north-south trending land-based P-wave seismic reflection profiles gathered across three urban areas in Seattle, Washington: West Seattle, central Seattle, and Mercer Island. The West Seattle profiles were collected with an accelerated weight drop source and 8 Hz vertical...
By
Natural Hazards Mission Area, Earthquake Hazards Program, Geologic Hazards Science Center

Miscellaneous Microtremor Array Datasets from the Puget Lowland, Washington State Miscellaneous Microtremor Array Datasets from the Puget Lowland, Washington State

Abstract: We compile three microtremor array datasets acquired in three campaigns in the Seattle and Tacoma basins, Washington State. These datasets were acquired between 2007 and 2018. Dataset 1 includes seven sites in the western Seattle and Tacoma basins acquired to image shear-wave velocity (Vs) in the upper 1 km that are suitable for analysis with microtremor methods not requiring...
By
Geologic Hazards Science Center
Filter Total Items: 63

Three-dimensional seismic velocity model for the Cascadia Subduction Zone with shallow soils and topography, version 1.7 Three-dimensional seismic velocity model for the Cascadia Subduction Zone with shallow soils and topography, version 1.7

The U.S. Geological Survey’s seismic velocity model for the Cascadia Subduction Zone provides P- and S-wave velocity (VP and VS, respectively) information from 40.2° to 50.0° N. latitude and −129.0° to −121.0° W. longitude, and is used to support a variety of research topics, including three-dimensional (3D) earthquake simulations and seismic hazard assessment in the Pacific Northwest...
Authors
Erin Wirth, Alex Grant, Ian Stone, William Stephenson, Arthur Frankel
By
Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center

Shallow faulting and folding beneath south‐central Seattle, Washington State, from land‐based high‐resolution seismic‐reflection imaging Shallow faulting and folding beneath south‐central Seattle, Washington State, from land‐based high‐resolution seismic‐reflection imaging

The geologic framework of the Seattle fault zone (SFZ) has been extensively studied, but the structure and fault strand locations in the central portion of the fault zone through the city of Seattle have remained controversial. Much of what is known about the SFZ has come from light detection and ranging (lidar)‐topographic surveys and paleoseismic investigations of fault scarps...
Authors
William Stephenson, Jack Odum, Thomas Pratt
By
Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center, Geologic Hazards Science Center

Empirical ground-motion basin response in the California Great Valley, Reno, Nevada, and Portland, Oregon Empirical ground-motion basin response in the California Great Valley, Reno, Nevada, and Portland, Oregon

We assess how well the Next-Generation Attenuation-West 2 (NGA-West2) ground-motion models (GMMs), which are used in the US Geological Survey’s (USGS) National Seismic Hazard Model (NSHM) for crustal faults in the western United States, predict the observed basin response in the Great Valley of California, the Reno basin in Nevada, and Portland and Tualatin basins in Oregon. These GMMs...
Authors
Sean Ahdi, Brad Aagaard, Morgan Moschetti, Grace Parker, Oliver Boyd, William Stephenson
By
Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center, Geologic Hazards Science Center

The 2023 US National Seismic Hazard Model: Ground-motion characterization for the conterminous United States The 2023 US National Seismic Hazard Model: Ground-motion characterization for the conterminous United States

We update the ground-motion characterization for the 2023 National Seismic Hazard Model (NSHM) for the conterminous United States. The update includes the use of new ground-motion models (GMMs) in the Cascadia subduction zone; an adjustment to the central and eastern United States (CEUS) GMMs to reduce misfits with observed data; an updated boundary for the application of GMMs for...
Authors
Morgan Moschetti, Brad Aagaard, Sean Ahdi, Jason Altekruse, Oliver Boyd, Arthur Frankel, Julie Herrick, Mark Petersen, Peter Powers, Sanaz Rezaeian, Allison Shumway, James Smith, William Stephenson, Eric Thompson, Kyle Withers
By
Geologic Hazards Science Center

The 2023 US 50-State National Seismic Hazard Model: Overview and implications The 2023 US 50-State National Seismic Hazard Model: Overview and implications

The US National Seismic Hazard Model (NSHM) was updated in 2023 for all 50 states using new science on seismicity, fault ruptures, ground motions, and probabilistic techniques to produce a standard of practice for public policy and other engineering applications (defined for return periods greater than ∼475 or less than ∼10,000 years). Changes in 2023 time-independent seismic hazard...
Authors
Mark Petersen, Allison Shumway, Peter Powers, Edward Field, Morgan Moschetti, Kishor Jaiswal, Kevin Milner, Sanaz Rezaeian, Arthur Frankel, Andrea Llenos, Andrew Michael, Jason Altekruse, Sean Ahdi, Kyle Withers, Charles Mueller, Yuehua Zeng, Robert Chase, Leah Salditch, Nico Luco, Kenneth S. Rukstales, Julie Herrick, Demi Girot, Brad Aagaard, Adrian Bender, Michael Blanpied, Richard Briggs, Oliver Boyd, Brandon Clayton, Christopher DuRoss, Eileen L. Evans, Peter J. Haeussler, Alexandra Hatem, Kirstie Haynie, Elizabeth Hearn, Kaj Johnson, Zachary Kortum, N. Kwong, Andrew Makdisi, Henry Mason, Daniel McNamara, Devin McPhillips, P. Okubo, Morgan Page, Frederick Pollitz, Justin Rubinstein, Bruce Shaw, Zheng-Kang Shen, Brian Shiro, James Smith, William Stephenson, Eric Thompson, Jessica Jobe, Erin Wirth, Robert C. Witter
By
Natural Hazards Mission Area, Earthquake Hazards Program, Geologic Hazards Science Center, Supplemental Appropriations for Disaster Recovery Activities

Implementation of basin models and sediment depth terms in the 2023 update of the U.S. National Seismic Hazard Model: Example from Reno, Nevada Implementation of basin models and sediment depth terms in the 2023 update of the U.S. National Seismic Hazard Model: Example from Reno, Nevada

We present a framework to evaluate the inclusion of candidate basin depth models in the U.S. Geological Survey National Seismic Hazard Model. We compute intensity measures (peak and spectral amplitudes) from uniformly processed earthquake ground motions in and around the basin of interest and compare these to ground-motion model (GMM) estimates over a range of oscillator periods. The...
Authors
Sean Ahdi, Morgan Moschetti, Brad Aagaard, Kaitlyn Abernathy, Oliver Boyd, William Stephenson
By
Natural Hazards Mission Area, Geologic Hazards Science Center
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