Fred F Pollitz
Fred Pollitz is a research geophysicist with the U.S. Geological Survey. He received his Ph.D in Geophysics (long-period seismology) from Princeton University in 1989, advised by Tony Dahlen.
As a postdoctoral researcher he switched focus to crustal deformation studies, motivated initially through collaboration with Dr. Selwyn Sacks at the Carnegie Institution of Washington. With the USGS since 2000, he has continued to work on problems related to crustal deformation and long-period seismology.
Education:
B.Sc. in Mathematics, Massachusetts Institute of Technology, Cambridge, MA USA (1984)
B.Sc. in Geophysics, Massachusetts Institute of Technology, Cambridge, MA USA (1984)
Ph.D. in Geophysics, Princeton University, Princeton, NJ USA (1989)
Professional Experience:
1997 to 2000: Postdoctoral Researcher, University of California, Davis
1995 to 1997: Isaac Newton Trust Postdoctoral Fellow, University of Cambridge, England
1993 to 1995: Alexander von Humboldt Postdoctoral Fellow, Geophysical Institute, Karlsruhe, Germany
1992 to 1993: CNRS Research Associate, Laboratoire de Sismologie, Institut de Physique du Globe, Paris
1989 to 1991: Postdoctoral Fellow, Department of Terrestrial Magnetism, Carnegie Institution of Washington
Honors and Offices:
2010 - First author of two of the 20 most cited `earthquake’ papers of the period
2000-2010
(http://www.sciencewatch.com/ana/st/earthquakes2/papers10yr/)
2002 - 2013 - Associate Editor, Bulletin of the Seismological Society of America
1998 - 2001 - Associate Editor, Journal of Geophysical Research
Science and Products
Seismic and geodetic analysis of rupture characteristics of the 2020 Mw 6.5 Monte Cristo Range, Nevada, earthquake
Exploring GPS observations of postseismic deformation following the 2012 MW7.8 Haida Gwaii and 2013 MW7.5 Craig, Alaska Earthquakes: Implications for viscoelastic Earth structure
Kinematics of fault slip associated with the July 4-6 2019 Ridgecrest, Californai earthquakes sequence
Coseismic and post-seismic gravity disturbance induced by seismic sources using a 2.5-D spectral element method
Coseismic slip and early afterslip of the M6.0 August 24, 2014 South Napa, California, earthquake
Lithosphere and shallow asthenosphere rheology from observations of post-earthquake relaxation
Induced seismicity reduces seismic hazard?
Fault slip associated with the 2 September 2017 M 5.3 Sulphur Peak, Idaho, earthquake and aftershock sequence
Induced seismicity reduces seismic hazard?
Sea level rise in the Samoan Islands escalated by viscoelastic relaxation after the 2009 Samoa‐Tonga earthquake
Surface imaging functions for elastic reverse time migration
Shallow microearthquakes near Chongqing, China triggered by the Rayleigh waves of the 2015 M7.8 Gorkha, Nepal earthquake
Science and Products
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- Publications
Filter Total Items: 49
Seismic and geodetic analysis of rupture characteristics of the 2020 Mw 6.5 Monte Cristo Range, Nevada, earthquake
The largest earthquake since 1954 to strike the state of Nevada, United States, ruptured on 15 May 2020 along the Monte Cristo range of west‐central Nevada. The Mw 6.5 event involved predominantly left‐lateral strike‐slip faulting with minor normal components on three aligned east–west‐trending faults that vary in strike by 23°. The kinematic rupture process is determined by joint inversion of GloAuthorsChengli Liu, Thorne Lay, Fred Pollitz, Jiao Xu, Xiong XiongExploring GPS observations of postseismic deformation following the 2012 MW7.8 Haida Gwaii and 2013 MW7.5 Craig, Alaska Earthquakes: Implications for viscoelastic Earth structure
The Queen Charlotte-Fairweather Fault (QC-FF) system off the coast of British Columbia and southeast Alaska is a highly active dextral strike-slip plate boundary that accommodates ∼50 mm/yr of relative motion between the Pacific and North America plates. Nine MW ≥ 6.7 earthquakes have occurred along the QC-FF system since 1910, including a MS(G-R)8.1 event in 1949. Two recent earthquakes, the OctoAuthorsKatherine A. Guns, Fred Pollitz, Thorne Lay, Han YueKinematics of fault slip associated with the July 4-6 2019 Ridgecrest, Californai earthquakes sequence
The 2019 Ridgecrest, California, earthquake sequence produced observable crustal deformation over much of central and southern California, as well as surface rupture over several tens of kilometers. To obtain a detailed picture of the fault slip involved in the 4 July M 6.4 foreshock and 6 July M 7.1 mainshock, we combine strong‐motion seismic waveforms with crustal deformation observations to obtAuthorsFred Pollitz, Jessica R. Murray, Jerry L. Svarc, Charles Wicks, Evelyn Roeloffs, Sarah E. Minson, Katherine Scharer, Katherine J. Kendrick, Kenneth W. Hudnut, Johanna Nevitt, Benjamin A. Brooks, David MencinCoseismic and post-seismic gravity disturbance induced by seismic sources using a 2.5-D spectral element method
I present a prescription for computing free-air coseismic and post-seismic gravity changes induced by seismic sources in a viscoelastic earth model. I assume a spherical earth geometry and a 2.5-D calculation, that is, 3-D motions that satisfy the equations of quasi-static equilibrium on a 2-D viscoelastic structure. The prescription permits application to regional gravity computations where a 2-DAuthorsFred PollitzCoseismic slip and early afterslip of the M6.0 August 24, 2014 South Napa, California, earthquake
We employ strong motion seismograms and static offsets from the Global Positioning System, Interferometric Synthetic Aperture Radar, and other measurements in order to derive a coseismic slip and afterslip model of the M6.0 24 August 2014 South Napa earthquake. This earthquake ruptured an ∼13‐km‐long portion of the West Napa fault with predominantly right‐lateral strike slip. In the kinematic seisAuthorsFred Pollitz, Jessica R. Murray, Sarah E. Minson, Charles W. Wicks, Jerry L. Svarc, Benjamin A. BrooksLithosphere and shallow asthenosphere rheology from observations of post-earthquake relaxation
In tectonically active regions, post-earthquake motions are generally shaped by a combination of continued fault slippage (afterslip) on a timescale of days to months and viscoelastic relaxation of the lower crust and upper mantle on a timescale of days to years. Transient crustal motions have been observed following numerous magnitude >~7 earthquakes in various tectonic settings: continental riftAuthorsFred PollitzInduced seismicity reduces seismic hazard?
Earthquakes caused by human activities have been observed for decades. Often these are related to industrial activities pumping fluids into deep geologic formations, like with wastewater disposal. The simplest theory connecting these processes to earthquakes is straightforward: injection leads to fluid pressure changes that either reduce the strength of preexisting faults or generate new faults. IAuthorsAndrew J. Barbour, Fred PollitzFault slip associated with the 2 September 2017 M 5.3 Sulphur Peak, Idaho, earthquake and aftershock sequence
The 2 September 2017 M 5.3 Sulphur Peak, Idaho, earthquake is one of the largest earthquakes in southern Idaho since the 1983 M 6.9 Borah Peak earthquake. It was followed by a vigorous aftershock sequence for nearly two weeks that included five events above M 4.5. The coseismic and early postseismic deformation was measured with both Interferometric Synthetic Aperture Radar and Global PositioningAuthorsFred Pollitz, Charles Wicks, William L. Yeck, James E. EvansInduced seismicity reduces seismic hazard?
Earthquakes caused by human activities have been observed for decades. Often these are related to industrial activities pumping fluids into deep geologic formations, like with wastewater disposal. The simplest theory connecting these processes to earthquakes is straightforward: injection leads to fluid pressure changes that either reduce the strength of preexisting faults or generate new faults. IAuthorsAndrew J. Barbour, Fred PollitzSea level rise in the Samoan Islands escalated by viscoelastic relaxation after the 2009 Samoa‐Tonga earthquake
The Samoan islands are an archipelago hosting a quarter million people mostly residing in three major islands, Savai'i and Upolu (Samoa), and Tutuila (American Samoa). The islands have experienced sea level rise by 2–3 mm/year during the last half century. The rate, however, has dramatically increased following the Mw 8.1 Samoa‐Tonga earthquake doublet (megathrust + normal faulting) in September 2AuthorsShin-Chan Han, Jeanne Sauber, Fred Pollitz, Richard RaySurface imaging functions for elastic reverse time migration
Reverse time migration is often used to interpret acoustic or three‐component seismic recordings by creating an image of subsurface seismic reflectors. Here I describe elastic reverse time migration imaging functions that are cast as waveform misfit sensitivity kernels of contrasts in material parameters across hypothetical seismic discontinuities, that is, specular reflectors. The proposed “surfaAuthorsFred PollitzShallow microearthquakes near Chongqing, China triggered by the Rayleigh waves of the 2015 M7.8 Gorkha, Nepal earthquake
We present a case of remotely triggered seismicity in Southwest China by the 2015/04/25 M7.8 Gorkha, Nepal earthquake. A local magnitude ML3.8 event occurred near the Qijiang district south of Chongqing city approximately 12 min after the Gorkha mainshock. Within 30km of this ML3.8 event there are 62 earthquakes since 2009 and only 7 ML>3events, which corresponds to a likelihood of 0.3% for a ML>3AuthorsLibo Han, Zhigang Peng, Christopher W. Johnson, Fred Pollitz, Lu Li, Baoshan Wang, Jing Wu, Qiang Li, Hongmei Wei - Software