William J Stephenson
Bill Stephensen is a scientist in the Earthquake Hazards Program.
Science and Products
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.
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.
Seismology in the City
Release Date: May 1, 2015 How seismologists can use noise to see under the ground.
Filter Total Items: 16
Microtremor Array Data from the Skagit River Delta, Washington State, 2025 Microtremor Array Data from the Skagit River Delta, Washington State, 2025
This data release contains seismic waveform data collected using nodal seismometers in the Skagit River Delta, WA. These data were acquired between July 21 and July 26, 2025 using SmartSolo IGU-16HR 3-component seismometers with a natural frequency of 5 Hz. Depending on site conditions, instruments were buried, partially buried, or placed on the ground surface (covered with a traffic...
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...
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...
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...
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...
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...
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...
Data Release for the 2023 U.S. 50-State National Seismic Hazard Model - Overview Data Release for the 2023 U.S. 50-State National Seismic Hazard Model - Overview
This data release contains data sets associated with the 2023 50-State National Seismic Hazard Model Update. The 2023 50-State National Seimsic Hazard Model (NSHM) Update includes an update to the NSHMs for the conterminous U.S (CONUS, last updated in 2018), Alaska (AK, last updated in 2007), and Hawaii (last updated in 2001). Data sets include inputs like seismicity catalogs used as...
Strike-slip in transtension: Complex crustal architecture of the Warm Springs Valley fault zone, northern Walker Lane Strike-slip in transtension: Complex crustal architecture of the Warm Springs Valley fault zone, northern Walker Lane
This data release contains field data for two P-wave seismic reflection profiles acquired across the Warm Springs Valley fault zone, part of the Northern Walker Lane, NV. The dataset consists of high-resolution seismic reflection field records in .segy format, shot coordinates in .csv format, and observers? logs in .pdf format. The high-resolution seismic profiles are approximately 4 km...
Seismic reflection imaging of the low-angle Panamint normal fault system, eastern California, 2018 Seismic reflection imaging of the low-angle Panamint normal fault system, eastern California, 2018
A fundamental question in seismic hazard analysis is whether
Digital datasets documenting subsurface data locations, topographic metrics, fault scarp mapping, and revised fault network for Crowley's Ridge, New Madrid Seismic Zone Digital datasets documenting subsurface data locations, topographic metrics, fault scarp mapping, and revised fault network for Crowley's Ridge, New Madrid Seismic Zone
This release provides the data and interpretations supporting evidence of late Quaternary faulting along Crowleys Ridge in the New Madrid seismic zone. The release includes location information for seismic reflection and airborne electromagnetic (AEM) data over Crowleys Ridge, a table of topographic metrics derived from analysis of the 10m National Elevation Dataset (NED) digital...
Spatially averaged coherencies (krSPAC) and Rayleigh effective-mode modeling of microtremor data from asymmetric arrays Spatially averaged coherencies (krSPAC) and Rayleigh effective-mode modeling of microtremor data from asymmetric arrays
The datasets for this investigation consist of microtremor array data collected at sites in San Jose, California, Pleasanton, California, and synthetic microtremor array data created as part of a blind shear-wave velocity modeling study as part of the Third International Symposium on the Effects of Surface Geology on Seismic Motion (ESG2006), Grenoble, France, 30 August - 1 September...
Filter Total Items: 69
The Cascadia Region Earthquake Science Center (CRESCENT): Advancing understanding of Cascadia's earthquake hazards The Cascadia Region Earthquake Science Center (CRESCENT): Advancing understanding of Cascadia's earthquake hazards
The Cascadia Subduction Zone (CSZ) is capable of producing large megathrust earthquakes and tsunamis, posing significant risks to the Pacific Northwest. This paper examines the seismic characteristics of the CSZ, including its offshore coupling, sparse seismicity, and a complex paleoseismic record. While recent advances in geophysical methods and data collection have improved our...
Authors
Diego Melgar, Amanda M. Thomas, Valerie J. Sahakian, Pieter-Ewald Share, Andrew Meigs, Harold Tobin, Lydia M. Staisch, Timothy Melbourne, Jill Elizabeth, Rasheed Ajala, Colin Amos, Loic Bachelot, Scott Bennett, James Biemiller, Brian Boston, Joseph Byrnes, Andy Clifford, Brendan Crowell, Jonathan Robert Delph, Benchun Duan, Eric Dunham, Tina Dura, Hannah Elston, Brittany Erickson, Shannon Fasola, Becky Fildes, Alice-Agnes Gabriel, Alex R. Grant, Alexandra Elise Hatem, Andrea Hawkes, Bin He, Eileen Hemphill-Haley, Brenton W. Hirao, Emilie Hooft, Yihe Huang, Jesse Hutchinson, Noel Jackson, Harvey Kelsey, Zoe Krauss, Ana Ledeczi, Ben Leshchinsky, Yajing Liu, Jack Loveless, Madeleine C. Lucas, William Marfo, Brett W. Maurer, Morgan P. Moschetti, Michael Olsen, Emily Roland, David Schmidt, Ignacio Sepulveda, Brandon Shuck, William J. Stephenson, Ashley Streig, Ian P. Stone, Chih-Hsuan Sung, Daniel Trugman, William S.D. Wilcock, Erin A. Wirth, Robert C. Witter, Emrah Yenier
Cascadia Subduction Zone science: Call for the next generation community seismic velocity model Cascadia Subduction Zone science: Call for the next generation community seismic velocity model
The Cascadia subduction zone (CSZ) hosts major seismic and tsunami hazards, yet key questions persist about the relationship between margin structure, fluid distribution, episodic tremor and slip, shallow megathrust behavior, shaking and tsunamigenesis, and the resulting hazard estimates. Addressing these problems requires an empirically grounded, three‐dimensional seismic velocity model...
Authors
Valerie J. Sahakian, Asif Ashraf, Charity Mann, Pieter-Ewald Share, Rasheed Ajala, Jonathan Delph, Bin He, Emilie Hooft, Alex R. Grant, William J. Stephenson, Erin A. Wirth, Amanda M. Thomas, Diego Melgar, Jill Elizabeth
Ground-motion characterization for the 2025 U.S. National Seismic Hazard Model for Puerto Rico and the U.S. Virgin Islands Ground-motion characterization for the 2025 U.S. National Seismic Hazard Model for Puerto Rico and the U.S. Virgin Islands
We develop the ground-motion characterization (GMC) for the 2025 U.S. National Seismic Hazard Model for Puerto Rico and the U.S. Virgin Islands (NSHM-PRVI) for earthquakes in active crustal, subduction interface, and subduction intraslab regimes. Using ground-motion models (GMMs) from the Next-Generation Attenuation (NGA)-West2 and NGA-Subduction projects, the GMC is parameterized by...
Authors
Morgan P. Moschetti, Brad T. Aagaard, Kyle B. Withers, Kevin Ross Milner, Jason M. Altekruse, Julie A. Herrick, Peter M. Powers, Sanaz Rezaeian, Allison M. Shumway, William J. Stephenson
Quantifying seismic properties of a river channel at Mount Rainier for use in debris flow monitoring and analysis Quantifying seismic properties of a river channel at Mount Rainier for use in debris flow monitoring and analysis
Theoretical models that relate debris flow properties to their seismic signature suggest seismic methods may be used to remotely characterize properties of these events. However, the complexity of debris flow sources and poorly constrained material properties in near‐surface environments limit our ability to determine important attributes of debris flows, such as volume and particle size
Authors
Avery E. Conner, Amanda M. Thomas, Kate E. Allstadt, Weston Thelen, Elaine A. Collins, Maxime Farin, William J. Stephenson, Alexandra M. Iezzi
Subsurface structure across the Tacoma Basin, Washington State, using trans-dimensional Bayesian inversion of fundamental mode spatial autocorrelation data Subsurface structure across the Tacoma Basin, Washington State, using trans-dimensional Bayesian inversion of fundamental mode spatial autocorrelation data
Spatial autocorrelation (SPAC), the azimuthal average of the normalized cross-correlation between equidistant station pairs deployed in a 2-D array, is widely used to image the subsurface structure. However, the rigorous estimate of subsurface structure and its uncertainties as a function of depth using SPAC data is challenging due to the nonlinear relation between the SPAC data and...
Authors
Surya Pachhai, Kristine L. Pankow, William J. Stephenson
Neotectonic origins for the Meadow Bank scarp, Wabash Valley seismic zone USA Neotectonic origins for the Meadow Bank scarp, Wabash Valley seismic zone USA
The Meadow Bank scarp (MBS) in southeastern Illinois is a linear geomorphic expression, ∼10 km long and ∼8 m high above a relatively flat landscape. It parallels an underlying northeast‐oriented Late‐Precambrian–Early‐Cambrian structural fabric, called the Wabash Valley fault zone, and is within an area of modern, historic, and paleo seismicity, called the Wabash Valley seismic zone. In...
Authors
Edward W Woolery, William J. Stephenson, Kevin Woller, Alena L. Leeds, Noah Silas Lindberg, Jackson K. Odum, Cooper Cearley, Ron Counts
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 A. Wirth, Alex R. Grant, Ian P. Stone, William J. Stephenson, Arthur D. Frankel
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 J. Stephenson, Jack K. Odum, Thomas L. Pratt
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 Kamran Ahdi, Brad T. Aagaard, Morgan P. Moschetti, Grace Alexandra Parker, Oliver S. Boyd, William J. Stephenson
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 P. Moschetti, Brad T. Aagaard, Sean Kamran Ahdi, Jason M. Altekruse, Oliver S. Boyd, Arthur D. Frankel, Julie A. Herrick, Mark D. Petersen, Peter M. Powers, Sanaz Rezaeian, Allison M. Shumway, James Andrew Smith, William J. Stephenson, Eric M. Thompson, Kyle B. Withers
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 D. Petersen, Allison M. Shumway, Peter M. Powers, Edward H. Field, Morgan P. Moschetti, Kishor S. Jaiswal, Kevin R. Milner, Sanaz Rezaeian, Arthur D. Frankel, Andrea L. Llenos, Andrew J. Michael, Jason M. Altekruse, Sean Kamran Ahdi, Kyle B. Withers, Charles Mueller, Yuehua Zeng, Robert E. Chase, Leah M. Salditch, Nico Luco, Kenneth S. Rukstales, Julie A. Herrick, Demi Leafar Girot, Brad T. Aagaard, Adrian Bender, Michael L. Blanpied, Richard W. Briggs, Oliver S. Boyd, Brandon S. Clayton, Christopher B. DuRoss, Eileen L. Evans, Peter J. Haeussler, Alexandra Elise Hatem, Kirstie Lafon Haynie, Elizabeth H. Hearn, Kaj M. Johnson, Zachary Alan Kortum, N. Simon Kwong, Andrew James Makdisi, Henry Mason, Daniel McNamara, Devin McPhillips, P. Okubo, Morgan T. Page, Frederick Pollitz, Justin L. Rubinstein, Bruce E. Shaw, Zheng-Kang Shen, Brian Shiro, James Andrew Smith, William J. Stephenson, Eric M. Thompson, Jessica A. Thompson Jobe, Erin A. Wirth, Robert C. Witter
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 Kamran Ahdi, Morgan P. Moschetti, Brad T. Aagaard, Kaitlyn Abernathy, Oliver S. Boyd, William J. Stephenson
Science and Products
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.
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.
Seismology in the City
Release Date: May 1, 2015 How seismologists can use noise to see under the ground.
Filter Total Items: 16
Microtremor Array Data from the Skagit River Delta, Washington State, 2025 Microtremor Array Data from the Skagit River Delta, Washington State, 2025
This data release contains seismic waveform data collected using nodal seismometers in the Skagit River Delta, WA. These data were acquired between July 21 and July 26, 2025 using SmartSolo IGU-16HR 3-component seismometers with a natural frequency of 5 Hz. Depending on site conditions, instruments were buried, partially buried, or placed on the ground surface (covered with a traffic...
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...
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...
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...
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...
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...
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...
Data Release for the 2023 U.S. 50-State National Seismic Hazard Model - Overview Data Release for the 2023 U.S. 50-State National Seismic Hazard Model - Overview
This data release contains data sets associated with the 2023 50-State National Seismic Hazard Model Update. The 2023 50-State National Seimsic Hazard Model (NSHM) Update includes an update to the NSHMs for the conterminous U.S (CONUS, last updated in 2018), Alaska (AK, last updated in 2007), and Hawaii (last updated in 2001). Data sets include inputs like seismicity catalogs used as...
Strike-slip in transtension: Complex crustal architecture of the Warm Springs Valley fault zone, northern Walker Lane Strike-slip in transtension: Complex crustal architecture of the Warm Springs Valley fault zone, northern Walker Lane
This data release contains field data for two P-wave seismic reflection profiles acquired across the Warm Springs Valley fault zone, part of the Northern Walker Lane, NV. The dataset consists of high-resolution seismic reflection field records in .segy format, shot coordinates in .csv format, and observers? logs in .pdf format. The high-resolution seismic profiles are approximately 4 km...
Seismic reflection imaging of the low-angle Panamint normal fault system, eastern California, 2018 Seismic reflection imaging of the low-angle Panamint normal fault system, eastern California, 2018
A fundamental question in seismic hazard analysis is whether
Digital datasets documenting subsurface data locations, topographic metrics, fault scarp mapping, and revised fault network for Crowley's Ridge, New Madrid Seismic Zone Digital datasets documenting subsurface data locations, topographic metrics, fault scarp mapping, and revised fault network for Crowley's Ridge, New Madrid Seismic Zone
This release provides the data and interpretations supporting evidence of late Quaternary faulting along Crowleys Ridge in the New Madrid seismic zone. The release includes location information for seismic reflection and airborne electromagnetic (AEM) data over Crowleys Ridge, a table of topographic metrics derived from analysis of the 10m National Elevation Dataset (NED) digital...
Spatially averaged coherencies (krSPAC) and Rayleigh effective-mode modeling of microtremor data from asymmetric arrays Spatially averaged coherencies (krSPAC) and Rayleigh effective-mode modeling of microtremor data from asymmetric arrays
The datasets for this investigation consist of microtremor array data collected at sites in San Jose, California, Pleasanton, California, and synthetic microtremor array data created as part of a blind shear-wave velocity modeling study as part of the Third International Symposium on the Effects of Surface Geology on Seismic Motion (ESG2006), Grenoble, France, 30 August - 1 September...
Filter Total Items: 69
The Cascadia Region Earthquake Science Center (CRESCENT): Advancing understanding of Cascadia's earthquake hazards The Cascadia Region Earthquake Science Center (CRESCENT): Advancing understanding of Cascadia's earthquake hazards
The Cascadia Subduction Zone (CSZ) is capable of producing large megathrust earthquakes and tsunamis, posing significant risks to the Pacific Northwest. This paper examines the seismic characteristics of the CSZ, including its offshore coupling, sparse seismicity, and a complex paleoseismic record. While recent advances in geophysical methods and data collection have improved our...
Authors
Diego Melgar, Amanda M. Thomas, Valerie J. Sahakian, Pieter-Ewald Share, Andrew Meigs, Harold Tobin, Lydia M. Staisch, Timothy Melbourne, Jill Elizabeth, Rasheed Ajala, Colin Amos, Loic Bachelot, Scott Bennett, James Biemiller, Brian Boston, Joseph Byrnes, Andy Clifford, Brendan Crowell, Jonathan Robert Delph, Benchun Duan, Eric Dunham, Tina Dura, Hannah Elston, Brittany Erickson, Shannon Fasola, Becky Fildes, Alice-Agnes Gabriel, Alex R. Grant, Alexandra Elise Hatem, Andrea Hawkes, Bin He, Eileen Hemphill-Haley, Brenton W. Hirao, Emilie Hooft, Yihe Huang, Jesse Hutchinson, Noel Jackson, Harvey Kelsey, Zoe Krauss, Ana Ledeczi, Ben Leshchinsky, Yajing Liu, Jack Loveless, Madeleine C. Lucas, William Marfo, Brett W. Maurer, Morgan P. Moschetti, Michael Olsen, Emily Roland, David Schmidt, Ignacio Sepulveda, Brandon Shuck, William J. Stephenson, Ashley Streig, Ian P. Stone, Chih-Hsuan Sung, Daniel Trugman, William S.D. Wilcock, Erin A. Wirth, Robert C. Witter, Emrah Yenier
Cascadia Subduction Zone science: Call for the next generation community seismic velocity model Cascadia Subduction Zone science: Call for the next generation community seismic velocity model
The Cascadia subduction zone (CSZ) hosts major seismic and tsunami hazards, yet key questions persist about the relationship between margin structure, fluid distribution, episodic tremor and slip, shallow megathrust behavior, shaking and tsunamigenesis, and the resulting hazard estimates. Addressing these problems requires an empirically grounded, three‐dimensional seismic velocity model...
Authors
Valerie J. Sahakian, Asif Ashraf, Charity Mann, Pieter-Ewald Share, Rasheed Ajala, Jonathan Delph, Bin He, Emilie Hooft, Alex R. Grant, William J. Stephenson, Erin A. Wirth, Amanda M. Thomas, Diego Melgar, Jill Elizabeth
Ground-motion characterization for the 2025 U.S. National Seismic Hazard Model for Puerto Rico and the U.S. Virgin Islands Ground-motion characterization for the 2025 U.S. National Seismic Hazard Model for Puerto Rico and the U.S. Virgin Islands
We develop the ground-motion characterization (GMC) for the 2025 U.S. National Seismic Hazard Model for Puerto Rico and the U.S. Virgin Islands (NSHM-PRVI) for earthquakes in active crustal, subduction interface, and subduction intraslab regimes. Using ground-motion models (GMMs) from the Next-Generation Attenuation (NGA)-West2 and NGA-Subduction projects, the GMC is parameterized by...
Authors
Morgan P. Moschetti, Brad T. Aagaard, Kyle B. Withers, Kevin Ross Milner, Jason M. Altekruse, Julie A. Herrick, Peter M. Powers, Sanaz Rezaeian, Allison M. Shumway, William J. Stephenson
Quantifying seismic properties of a river channel at Mount Rainier for use in debris flow monitoring and analysis Quantifying seismic properties of a river channel at Mount Rainier for use in debris flow monitoring and analysis
Theoretical models that relate debris flow properties to their seismic signature suggest seismic methods may be used to remotely characterize properties of these events. However, the complexity of debris flow sources and poorly constrained material properties in near‐surface environments limit our ability to determine important attributes of debris flows, such as volume and particle size
Authors
Avery E. Conner, Amanda M. Thomas, Kate E. Allstadt, Weston Thelen, Elaine A. Collins, Maxime Farin, William J. Stephenson, Alexandra M. Iezzi
Subsurface structure across the Tacoma Basin, Washington State, using trans-dimensional Bayesian inversion of fundamental mode spatial autocorrelation data Subsurface structure across the Tacoma Basin, Washington State, using trans-dimensional Bayesian inversion of fundamental mode spatial autocorrelation data
Spatial autocorrelation (SPAC), the azimuthal average of the normalized cross-correlation between equidistant station pairs deployed in a 2-D array, is widely used to image the subsurface structure. However, the rigorous estimate of subsurface structure and its uncertainties as a function of depth using SPAC data is challenging due to the nonlinear relation between the SPAC data and...
Authors
Surya Pachhai, Kristine L. Pankow, William J. Stephenson
Neotectonic origins for the Meadow Bank scarp, Wabash Valley seismic zone USA Neotectonic origins for the Meadow Bank scarp, Wabash Valley seismic zone USA
The Meadow Bank scarp (MBS) in southeastern Illinois is a linear geomorphic expression, ∼10 km long and ∼8 m high above a relatively flat landscape. It parallels an underlying northeast‐oriented Late‐Precambrian–Early‐Cambrian structural fabric, called the Wabash Valley fault zone, and is within an area of modern, historic, and paleo seismicity, called the Wabash Valley seismic zone. In...
Authors
Edward W Woolery, William J. Stephenson, Kevin Woller, Alena L. Leeds, Noah Silas Lindberg, Jackson K. Odum, Cooper Cearley, Ron Counts
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 A. Wirth, Alex R. Grant, Ian P. Stone, William J. Stephenson, Arthur D. Frankel
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 J. Stephenson, Jack K. Odum, Thomas L. Pratt
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 Kamran Ahdi, Brad T. Aagaard, Morgan P. Moschetti, Grace Alexandra Parker, Oliver S. Boyd, William J. Stephenson
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 P. Moschetti, Brad T. Aagaard, Sean Kamran Ahdi, Jason M. Altekruse, Oliver S. Boyd, Arthur D. Frankel, Julie A. Herrick, Mark D. Petersen, Peter M. Powers, Sanaz Rezaeian, Allison M. Shumway, James Andrew Smith, William J. Stephenson, Eric M. Thompson, Kyle B. Withers
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 D. Petersen, Allison M. Shumway, Peter M. Powers, Edward H. Field, Morgan P. Moschetti, Kishor S. Jaiswal, Kevin R. Milner, Sanaz Rezaeian, Arthur D. Frankel, Andrea L. Llenos, Andrew J. Michael, Jason M. Altekruse, Sean Kamran Ahdi, Kyle B. Withers, Charles Mueller, Yuehua Zeng, Robert E. Chase, Leah M. Salditch, Nico Luco, Kenneth S. Rukstales, Julie A. Herrick, Demi Leafar Girot, Brad T. Aagaard, Adrian Bender, Michael L. Blanpied, Richard W. Briggs, Oliver S. Boyd, Brandon S. Clayton, Christopher B. DuRoss, Eileen L. Evans, Peter J. Haeussler, Alexandra Elise Hatem, Kirstie Lafon Haynie, Elizabeth H. Hearn, Kaj M. Johnson, Zachary Alan Kortum, N. Simon Kwong, Andrew James Makdisi, Henry Mason, Daniel McNamara, Devin McPhillips, P. Okubo, Morgan T. Page, Frederick Pollitz, Justin L. Rubinstein, Bruce E. Shaw, Zheng-Kang Shen, Brian Shiro, James Andrew Smith, William J. Stephenson, Eric M. Thompson, Jessica A. Thompson Jobe, Erin A. Wirth, Robert C. Witter
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 Kamran Ahdi, Morgan P. Moschetti, Brad T. Aagaard, Kaitlyn Abernathy, Oliver S. Boyd, William J. Stephenson