William Barnhart is an Assistant Coordinator of the Earthquake Hazards Program.
Science and Products
Coseismic surface displacement in the 2019 ridgecrest earthquakes: Comparison of field measurements and optical image correlation results
A fundamental topic in earthquake studies is understanding the extent to which fault rupture at the surface is localized on primary fault strands as opposed to distributed tens to hundreds of meters away from primary ruptures through off‐fault deformation (OFD) via a combination of discrete secondary faulting and bulk deformation. The 2019 Ridgecrest, CA Mw6.4 and Mw7.1 earthquakes provide an oppo
Localized fault-zone dilatancy and surface inelasticity of the 2019 Ridgecrest earthquakes
Earthquakes produce a spectrum of elastic and inelastic deformation processes that are reflected across various length and time scales. While elasticity has long dominated research assumptions in active tectonics, increasing interest has focused on the inelastic characteristics of earthquakes, particularly those of the surface fault rupture zone itself, and how they relate to ground rupture hazard
Surface rupture and distributed deformation revealed by optical satellite imagery: The intraplate 2016 Mw 6.0 Petermann Ranges earthquake, Australia
High-resolution optical satellite imagery is used to quantify vertical surface deformation associated with the intraplate 20 May 2016 Mw 6.0 Petermann Ranges earthquake, Northern Territory, Australia. The 21 ╓ 1 km long NW-trending rupture resulted from reverse motion on a northeast-dipping fault. Vertical surface offsets of up to 0.7 ╓ 0.1 m distributed across a 0.5-to-1 km wide deformation zone
Vertical coseismic offsets from differential high-resolution stereogrammetric DSMs: The 2013 Baluchistan, Pakistan earthquake
The recent proliferation of high-resolution (< 3-m spatial resolution) digital topography datasets opens a spectrum of geodetic applications in differential topography, including the quantification of coseismic vertical displacement fields. Most investigations of coseismic vertical displacements to date rely, in part, on pre- or post-event lidar surveys that are intractable or non-existent in many
The 12 November 2017 Mw 7.3 Ezgeleh–Sarpolzahab (Iran) earthquake and active tectonics of the Lurestan arc
The 12 November 2017 Mw 7.3 Ezgeleh‐Sarpolzahab earthquake is the largest instrumentally recorded earthquake in the Zagros Simply Folded Belt by a factor of ∼10 in seismic moment. Exploiting local, regional, and teleseismic data and synthetic aperture radar interferometry imagery, we characterize the rupture, its aftershock sequence, background seismicity, and regional tectonics. The mainshock rup
Induced earthquake and liquefaction hazards in Oklahoma, USA: Constraints from InSAR
Oklahoma experienced three earthquakes of Mw5.0 or greater in 2016: the 13-Feb. Fairview earthquake (Mw5.1), the 03-Sep. Pawnee earthquake (Mw5.8), and the 07-Nov. Cushing earthquake (Mw5.0). These events are the first earthquakes in the state exceeding Mw5.0 since the 2011 Mw5.7 Prague earthquake and likely result from wide-scale deep fluid-injection. We use interferometric synthetic aperture rad
Integrated geophysical characteristics of the 2015 Illapel, Chile, earthquake
On 16 September 2015, a Mw 8.3 earthquake ruptured the subduction zone offshore of Illapel, Chile, generating an aftershock sequence with 14 Mw 6.0–7.0 events. A double source W phase moment tensor inversion consists of a Mw 7.2 subevent and the main Mw 8.2 phase. We determine two slip models for the mainshock, one using teleseismic broadband waveforms and the other using static GPS and InSAR surf
The 2008 Wells, Nevada earthquake sequence: Source constraints using calibrated multiple event relocation and InSAR
The 2008 Wells, NV earthquake represents the largest domestic event in the conterminous U.S. outside of California since the October 1983 Borah Peak earthquake in southern Idaho. We present an improved catalog, magnitude complete to 1.6, of the foreshock-aftershock sequence, supplementing the current U.S. Geological Survey (USGS) Preliminary Determination of Epicenters (PDE) catalog with 1,928 wel
Oklahoma experiences largest earthquake during ongoing regional wastewater injection hazard mitigation efforts
The 3 September 2016, Mw 5.8 Pawnee earthquake was the largest recorded earthquake in the state of Oklahoma. Seismic and geodetic observations of the Pawnee sequence, including precise hypocenter locations and moment tensor modeling, shows that the Pawnee earthquake occurred on a previously unknown left-lateral strike-slip basement fault that intersects the mapped right-lateral Labette fault zone.
On- and off-fault deformation associated with the September 2013 Mw7.7 Balochistan earthquake: Implications for geologic slip rate measurements
The 24 September 2013 Mw7.7 Balochistan, Pakistan earthquake ruptured a ~ 200 km-long stretch of the Hoshab fault in southern Pakistan and produced the second-largest lateral surface displacement observed for a continental strike-slip earthquake. We remotely measured surface deformation associated with this event using high-resolution (0.5 m) pre- and post-event satellite optical imagery. We docum
Evidence for slip partitioning and bimodal slip behavior on a single fault: Surface slip characteristics of the 2013 Mw7.7 Balochistan, Pakistan earthquake
Deformation is commonly accommodated by strain partitioning on multiple, independent strike-slip and dip-slip faults in continental settings of oblique plate convergence. As a corollary, individual faults tend to exhibit one sense of slip – normal, reverse, or strike-slip – until whole-scale changes in boundary conditions reactivate preexisting faults in a new deformation regime. In this study, we
Coseismic surface displacement and fault zone width measurements in the 2019 Ridgecrest earthquakes from WorldView optical image correlation
(1) Lateral displacement measurements made based on optical image correlation results from WorldView satellite images along with (2) local and regional rupture width measurements for the 2019 Mw6.4 and Mw7.1 Ridgecrest earthquakes, CA. These datasets are associated with the publication: Gold, R. D., DuRoss, C. B., &amp; Barnhart, W. D., 2021, Coseismic surface displacement in the 2019 Ridgec
Science and Products
- Publications
Coseismic surface displacement in the 2019 ridgecrest earthquakes: Comparison of field measurements and optical image correlation results
A fundamental topic in earthquake studies is understanding the extent to which fault rupture at the surface is localized on primary fault strands as opposed to distributed tens to hundreds of meters away from primary ruptures through off‐fault deformation (OFD) via a combination of discrete secondary faulting and bulk deformation. The 2019 Ridgecrest, CA Mw6.4 and Mw7.1 earthquakes provide an oppoLocalized fault-zone dilatancy and surface inelasticity of the 2019 Ridgecrest earthquakes
Earthquakes produce a spectrum of elastic and inelastic deformation processes that are reflected across various length and time scales. While elasticity has long dominated research assumptions in active tectonics, increasing interest has focused on the inelastic characteristics of earthquakes, particularly those of the surface fault rupture zone itself, and how they relate to ground rupture hazardSurface rupture and distributed deformation revealed by optical satellite imagery: The intraplate 2016 Mw 6.0 Petermann Ranges earthquake, Australia
High-resolution optical satellite imagery is used to quantify vertical surface deformation associated with the intraplate 20 May 2016 Mw 6.0 Petermann Ranges earthquake, Northern Territory, Australia. The 21 ╓ 1 km long NW-trending rupture resulted from reverse motion on a northeast-dipping fault. Vertical surface offsets of up to 0.7 ╓ 0.1 m distributed across a 0.5-to-1 km wide deformation zoneVertical coseismic offsets from differential high-resolution stereogrammetric DSMs: The 2013 Baluchistan, Pakistan earthquake
The recent proliferation of high-resolution (< 3-m spatial resolution) digital topography datasets opens a spectrum of geodetic applications in differential topography, including the quantification of coseismic vertical displacement fields. Most investigations of coseismic vertical displacements to date rely, in part, on pre- or post-event lidar surveys that are intractable or non-existent in manyThe 12 November 2017 Mw 7.3 Ezgeleh–Sarpolzahab (Iran) earthquake and active tectonics of the Lurestan arc
The 12 November 2017 Mw 7.3 Ezgeleh‐Sarpolzahab earthquake is the largest instrumentally recorded earthquake in the Zagros Simply Folded Belt by a factor of ∼10 in seismic moment. Exploiting local, regional, and teleseismic data and synthetic aperture radar interferometry imagery, we characterize the rupture, its aftershock sequence, background seismicity, and regional tectonics. The mainshock rupInduced earthquake and liquefaction hazards in Oklahoma, USA: Constraints from InSAR
Oklahoma experienced three earthquakes of Mw5.0 or greater in 2016: the 13-Feb. Fairview earthquake (Mw5.1), the 03-Sep. Pawnee earthquake (Mw5.8), and the 07-Nov. Cushing earthquake (Mw5.0). These events are the first earthquakes in the state exceeding Mw5.0 since the 2011 Mw5.7 Prague earthquake and likely result from wide-scale deep fluid-injection. We use interferometric synthetic aperture radIntegrated geophysical characteristics of the 2015 Illapel, Chile, earthquake
On 16 September 2015, a Mw 8.3 earthquake ruptured the subduction zone offshore of Illapel, Chile, generating an aftershock sequence with 14 Mw 6.0–7.0 events. A double source W phase moment tensor inversion consists of a Mw 7.2 subevent and the main Mw 8.2 phase. We determine two slip models for the mainshock, one using teleseismic broadband waveforms and the other using static GPS and InSAR surfThe 2008 Wells, Nevada earthquake sequence: Source constraints using calibrated multiple event relocation and InSAR
The 2008 Wells, NV earthquake represents the largest domestic event in the conterminous U.S. outside of California since the October 1983 Borah Peak earthquake in southern Idaho. We present an improved catalog, magnitude complete to 1.6, of the foreshock-aftershock sequence, supplementing the current U.S. Geological Survey (USGS) Preliminary Determination of Epicenters (PDE) catalog with 1,928 welOklahoma experiences largest earthquake during ongoing regional wastewater injection hazard mitigation efforts
The 3 September 2016, Mw 5.8 Pawnee earthquake was the largest recorded earthquake in the state of Oklahoma. Seismic and geodetic observations of the Pawnee sequence, including precise hypocenter locations and moment tensor modeling, shows that the Pawnee earthquake occurred on a previously unknown left-lateral strike-slip basement fault that intersects the mapped right-lateral Labette fault zone.On- and off-fault deformation associated with the September 2013 Mw7.7 Balochistan earthquake: Implications for geologic slip rate measurements
The 24 September 2013 Mw7.7 Balochistan, Pakistan earthquake ruptured a ~ 200 km-long stretch of the Hoshab fault in southern Pakistan and produced the second-largest lateral surface displacement observed for a continental strike-slip earthquake. We remotely measured surface deformation associated with this event using high-resolution (0.5 m) pre- and post-event satellite optical imagery. We documEvidence for slip partitioning and bimodal slip behavior on a single fault: Surface slip characteristics of the 2013 Mw7.7 Balochistan, Pakistan earthquake
Deformation is commonly accommodated by strain partitioning on multiple, independent strike-slip and dip-slip faults in continental settings of oblique plate convergence. As a corollary, individual faults tend to exhibit one sense of slip – normal, reverse, or strike-slip – until whole-scale changes in boundary conditions reactivate preexisting faults in a new deformation regime. In this study, we - Data
Coseismic surface displacement and fault zone width measurements in the 2019 Ridgecrest earthquakes from WorldView optical image correlation
(1) Lateral displacement measurements made based on optical image correlation results from WorldView satellite images along with (2) local and regional rupture width measurements for the 2019 Mw6.4 and Mw7.1 Ridgecrest earthquakes, CA. These datasets are associated with the publication: Gold, R. D., DuRoss, C. B., &amp; Barnhart, W. D., 2021, Coseismic surface displacement in the 2019 Ridgec