William J Stephenson
Bill Stephensen is a scientist in the Earthquake Hazards Program.
Science and Products
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Seismic imaging beneath an InSAR anomaly in eastern Washington State: Shallow faulting associated with an earthquake swarm in a low-hazard area Seismic imaging beneath an InSAR anomaly in eastern Washington State: Shallow faulting associated with an earthquake swarm in a low-hazard area
In 2001, a rare swarm of small, shallow earthquakes beneath the city of Spokane, Washington, caused ground shaking as well as audible booms over a five‐month period. Subsequent Interferometric Synthetic Aperture Radar (InSAR) data analysis revealed an area of surface uplift in the vicinity of the earthquake swarm. To investigate the potential faults that may have caused both the...
Authors
William Stephenson, Jackson K. Odum, Charles Wicks, Thomas Pratt, Richard Blakely
Preliminary assessment of a previously unknown fault zone beneath the Daytona Beach sand blow cluster near Marianna, Arkansas Preliminary assessment of a previously unknown fault zone beneath the Daytona Beach sand blow cluster near Marianna, Arkansas
We collected new high‐resolution P‐wave seismic‐reflection data to explore for possible faults beneath a roughly linear cluster of early to mid‐Holocene earthquake‐induced sand blows to the south of Marianna, Arkansas. The Daytona Beach sand blow deposits are located in east‐central Arkansas about 75 km southwest of Memphis, Tennessee, and about 80 km south of the southwestern end of the...
Authors
Jackson K. Odum, Robert Williams, William Stephenson, Martitia Tuttle, Hadar Al-Shukri
Comparisons between vs30 and spectral response for 30 sites in Newcastle, Australia from collocated seismic cone penetrometer, active- and passive-source vs data Comparisons between vs30 and spectral response for 30 sites in Newcastle, Australia from collocated seismic cone penetrometer, active- and passive-source vs data
Although the time‐averaged shear‐wave velocity down to 30 m depth (VS30) can be a proxy for estimating earthquake ground‐motion amplification, significant controversy exists about its limitations when used as a single parameter for the prediction of amplification. To examine this question in absence of relevant strong‐motion records, we use a range of different methods to measure the...
Authors
Theodora Volti, David Burbidge, Clive Collins, Michael Asten, Jackson K. Odum, William Stephenson, Chris Pascal, Josef Holzschuh
High-resolution seismic reflection imaging of growth folding and shallow faults beneath the Southern Puget Lowland, Washington State High-resolution seismic reflection imaging of growth folding and shallow faults beneath the Southern Puget Lowland, Washington State
Marine seismic reflection data from southern Puget Sound, Washington, were collected to investigate the nature of shallow structures associated with the Tacoma fault zone and the Olympia structure. Growth folding and probable Holocene surface deformation were imaged within the Tacoma fault zone beneath Case and Carr Inlets. Shallow faults near potential field anomalies associated with...
Authors
Jackson K. Odum, William Stephenson, Thomas Pratt, Richard Blakely
Compilation of VS30 Data for the United States Compilation of VS30 Data for the United States
VS30, the time-averaged shear-wave velocity (VS) to a depth of 30 meters, is a key index adopted by the earthquake engineering community to account for seismic site conditions. VS30 is typically based on geophysical measurements of VS derived from invasive and noninvasive techniques at sites of interest. Owing to cost considerations, as well as logistical and environmental concerns, VS30...
Authors
Alan Yong, Eric M. Thompson, David Wald, Keith Knudsen, Jack Odum, William Stephenson, Scott Haefner
Kinematics of shallow backthrusts in the Seattle fault zone, Washington State Kinematics of shallow backthrusts in the Seattle fault zone, Washington State
Near-surface thrust fault splays and antithetic backthrusts at the tips of major thrust fault systems can distribute slip across multiple shallow fault strands, complicating earthquake hazard analyses based on studies of surface faulting. The shallow expression of the fault strands forming the Seattle fault zone of Washington State shows the structural relationships and interactions...
Authors
Thomas Pratt, K.G. Troost, Jackson K. Odum, William Stephenson
Science and Products
Filter Total Items: 15
No Result Found
Filter Total Items: 63
Seismic imaging beneath an InSAR anomaly in eastern Washington State: Shallow faulting associated with an earthquake swarm in a low-hazard area Seismic imaging beneath an InSAR anomaly in eastern Washington State: Shallow faulting associated with an earthquake swarm in a low-hazard area
In 2001, a rare swarm of small, shallow earthquakes beneath the city of Spokane, Washington, caused ground shaking as well as audible booms over a five‐month period. Subsequent Interferometric Synthetic Aperture Radar (InSAR) data analysis revealed an area of surface uplift in the vicinity of the earthquake swarm. To investigate the potential faults that may have caused both the...
Authors
William Stephenson, Jackson K. Odum, Charles Wicks, Thomas Pratt, Richard Blakely
Preliminary assessment of a previously unknown fault zone beneath the Daytona Beach sand blow cluster near Marianna, Arkansas Preliminary assessment of a previously unknown fault zone beneath the Daytona Beach sand blow cluster near Marianna, Arkansas
We collected new high‐resolution P‐wave seismic‐reflection data to explore for possible faults beneath a roughly linear cluster of early to mid‐Holocene earthquake‐induced sand blows to the south of Marianna, Arkansas. The Daytona Beach sand blow deposits are located in east‐central Arkansas about 75 km southwest of Memphis, Tennessee, and about 80 km south of the southwestern end of the...
Authors
Jackson K. Odum, Robert Williams, William Stephenson, Martitia Tuttle, Hadar Al-Shukri
Comparisons between vs30 and spectral response for 30 sites in Newcastle, Australia from collocated seismic cone penetrometer, active- and passive-source vs data Comparisons between vs30 and spectral response for 30 sites in Newcastle, Australia from collocated seismic cone penetrometer, active- and passive-source vs data
Although the time‐averaged shear‐wave velocity down to 30 m depth (VS30) can be a proxy for estimating earthquake ground‐motion amplification, significant controversy exists about its limitations when used as a single parameter for the prediction of amplification. To examine this question in absence of relevant strong‐motion records, we use a range of different methods to measure the...
Authors
Theodora Volti, David Burbidge, Clive Collins, Michael Asten, Jackson K. Odum, William Stephenson, Chris Pascal, Josef Holzschuh
High-resolution seismic reflection imaging of growth folding and shallow faults beneath the Southern Puget Lowland, Washington State High-resolution seismic reflection imaging of growth folding and shallow faults beneath the Southern Puget Lowland, Washington State
Marine seismic reflection data from southern Puget Sound, Washington, were collected to investigate the nature of shallow structures associated with the Tacoma fault zone and the Olympia structure. Growth folding and probable Holocene surface deformation were imaged within the Tacoma fault zone beneath Case and Carr Inlets. Shallow faults near potential field anomalies associated with...
Authors
Jackson K. Odum, William Stephenson, Thomas Pratt, Richard Blakely
Compilation of VS30 Data for the United States Compilation of VS30 Data for the United States
VS30, the time-averaged shear-wave velocity (VS) to a depth of 30 meters, is a key index adopted by the earthquake engineering community to account for seismic site conditions. VS30 is typically based on geophysical measurements of VS derived from invasive and noninvasive techniques at sites of interest. Owing to cost considerations, as well as logistical and environmental concerns, VS30...
Authors
Alan Yong, Eric M. Thompson, David Wald, Keith Knudsen, Jack Odum, William Stephenson, Scott Haefner
Kinematics of shallow backthrusts in the Seattle fault zone, Washington State Kinematics of shallow backthrusts in the Seattle fault zone, Washington State
Near-surface thrust fault splays and antithetic backthrusts at the tips of major thrust fault systems can distribute slip across multiple shallow fault strands, complicating earthquake hazard analyses based on studies of surface faulting. The shallow expression of the fault strands forming the Seattle fault zone of Washington State shows the structural relationships and interactions...
Authors
Thomas Pratt, K.G. Troost, Jackson K. Odum, William Stephenson