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
Proceedings of the 11th United States-Japan natural resources panel for earthquake research, Napa Valley, California, November 16–18, 2016
Viscoelastic lower crust and mantle relaxation following the 14–16 April 2016 Kumamoto, Japan, earthquake sequence
Connecting crustal seismicity and earthquake-driven stress evolution in Southern California
A note on adding viscoelasticity to earthquake simulators
Geodetic slip model of the 3 September 2016 Mw 5.8 Pawnee, Oklahoma, earthquake: Evidence for fault‐zone collapse
Implications of the earthquake cycle for inferring fault locking on the Cascadia megathrust
Persistent slip rate discrepancies in the eastern California (USA) shear zone
The Earthquake‐Source Inversion Validation (SIV) Project
Postseismic gravity change after the 2006–2007 great earthquake doublet and constraints on the asthenosphere structure in the central Kuril Islands
Lithospheric rheology constrained from twenty-five years of postseismic deformation following the 1989 Mw 6.9 Loma Prieta earthquake
Seismic velocity structure of the crust and shallow mantle of the Central and Eastern United States by seismic surface wave imaging
Regional seismic-wave propagation from the M5.8 23 August 2011, Mineral, Virginia, earthquake
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Filter Total Items: 49
Proceedings of the 11th United States-Japan natural resources panel for earthquake research, Napa Valley, California, November 16–18, 2016
The UJNR Panel on Earthquake Research promotes advanced research toward a more fundamental understanding of the earthquake process and hazard estimation. The Eleventh Joint meeting was extremely beneficial in furthering cooperation and deepening understanding of problems common to both Japan and the United States.The meeting included productive exchanges of information on approaches to systematicViscoelastic lower crust and mantle relaxation following the 14–16 April 2016 Kumamoto, Japan, earthquake sequence
The 2016 Kumamoto, Japan, earthquake sequence, culminating in the Mw=7.0 16 April 2016 main shock, occurred within an active tectonic belt of central Kyushu. GPS data from GEONET reveal transient crustal motions from several millimeters per year up to ∼3 cm/yr during the first 8.5 months following the sequence. The spatial pattern of horizontal postseismic motions is shaped by both shallow afterslAuthorsFred Pollitz, Tomokazu Kobayashi, Hiroshi Yarai, Bunichiro Shibazaki, Takumi MatsumotoConnecting crustal seismicity and earthquake-driven stress evolution in Southern California
Tectonic stress in the crust evolves during a seismic cycle, with slow stress accumulation over interseismic periods, episodic stress steps at the time of earthquakes, and transient stress readjustment during a postseismic period that may last months to years. Static stress transfer to surrounding faults has been well documented to alter regional seismicity rates over both short and long time scalAuthorsFred Pollitz, Camilla CattaniaA note on adding viscoelasticity to earthquake simulators
Here, I describe how time‐dependent quasi‐static stress transfer can be implemented in an earthquake simulator code that is used to generate long synthetic seismicity catalogs. Most existing seismicity simulators use precomputed static stress interaction coefficients to rapidly implement static stress transfer in fault networks with typically tens of thousands of fault patches. The extension to quAuthorsFred PollitzGeodetic slip model of the 3 September 2016 Mw 5.8 Pawnee, Oklahoma, earthquake: Evidence for fault‐zone collapse
The 3 September 2016 Mw 5.8 Pawnee earthquake in northern Oklahoma is the largest earthquake ever recorded in Oklahoma. The coseismic deformation was measured with both Interferometric Synthetic Aperture Radar and Global Positioning System (GPS), with measureable signals of order 1 cm and 1 mm, respectively. We derive a coseismic slip model from Sentinel‐1A and Radarsat 2 interferograms and GPS stAuthorsFred Pollitz, Charles W. Wicks, Martin Schoenball, William L. Ellsworth, Mark MurrayImplications of the earthquake cycle for inferring fault locking on the Cascadia megathrust
GPS velocity fields in the Western US have been interpreted with various physical models of the lithosphere-asthenosphere system: (1) time-independent block models; (2) time-dependent viscoelastic-cycle models, where deformation is driven by viscoelastic relaxation of the lower crust and upper mantle from past faulting events; (3) viscoelastic block models, a time-dependent variation of the blockAuthorsFred Pollitz, Eileen EvansPersistent slip rate discrepancies in the eastern California (USA) shear zone
Understanding fault slip rates in the eastern California shear zone (ECSZ) using GPS geodesy is complicated by potentially overlapping strain signals due to many sub-parallel strike-slip faults and by inconsistencies with geologic slip rates. The role of fault system geometry in describing ECSZ deformation may be investigated with total variation regularization, which algorithmically determines aAuthorsEileen Evans, Wayne R. Thatcher, Fred Pollitz, Jessica R. MurrayThe Earthquake‐Source Inversion Validation (SIV) Project
Finite‐fault earthquake source inversions infer the (time‐dependent) displacement on the rupture surface from geophysical data. The resulting earthquake source models document the complexity of the rupture process. However, multiple source models for the same earthquake, obtained by different research teams, often exhibit remarkable dissimilarities. To address the uncertainties in earthquake‐soAuthorsP. Martin Mai, Danijel Schorlemmer, Morgan T. Page, Jean-Paul Ampuero, Kimiyuki Asano, Mathieu Causse, Susana Custodio, Wenyuan Fan, Gaetano Festa, Martin Galis, Frantisek Gallovic, Walter Imperatori, Martin Käser, Dmytro Malytskyy, Ryo Okuwaki, Fred Pollitz, Luca Passone, Hoby N. T. Razafindrakoto, Haruko Sekiguchi, Seok Goo Song, Surendra N. Somala, Kiran K. S. Thingbaijam, Cedric Twardzik, Martin van Driel, Jagdish C. Vyas, Rongjiang Wang, Yuji Yagi, Olaf ZielkePostseismic gravity change after the 2006–2007 great earthquake doublet and constraints on the asthenosphere structure in the central Kuril Islands
Large earthquakes often trigger viscoelastic adjustment for years to decades depending on the rheological properties and the nature and spatial extent of coseismic stress. The 2006 Mw8.3 thrust and 2007 Mw8.1 normal fault earthquakes of the central Kuril Islands resulted in significant postseismic gravity change in Gravity Recovery and Climate Experiment (GRACE) but without a discernible coseismicAuthorsShin-Chan Han, Jeanne Sauber, Fred PollitzLithospheric rheology constrained from twenty-five years of postseismic deformation following the 1989 Mw 6.9 Loma Prieta earthquake
The October 17, 1989 Mw 6.9 Loma Prieta earthquake provides the first opportunity of probing the crustal and upper mantle rheology in the San Francisco Bay Area since the 1906 Mw 7.9 San Francisco earthquake. Here we use geodetic observations including GPS and InSAR to characterize the Loma Prieta earthquake postseismic displacements from 1989 to 2013. Pre-earthquake deformation rates are constraiAuthorsMong-Han Huang, Roland Burgmann, Fred PollitzSeismic velocity structure of the crust and shallow mantle of the Central and Eastern United States by seismic surface wave imaging
Seismic surface waves from the Transportable Array of EarthScope's USArray are used to estimate phase velocity structure of 18 to 125 s Rayleigh waves, then inverted to obtain three-dimensional crust and upper mantle structure of the Central and Eastern United States (CEUS) down to ∼200 km. The obtained lithosphere structure confirms previously imaged CEUS features, e.g., the low seismic-velocityAuthorsFred Pollitz, Walter D. MooneyRegional seismic-wave propagation from the M5.8 23 August 2011, Mineral, Virginia, earthquake
The M5.8 23 August 2011 Mineral, Virginia, earthquake was felt over nearly the entire eastern United States and was recorded by a wide array of seismic broadband instruments. The earthquake occurred ~200 km southeast of the boundary between two distinct geologic belts, the Piedmont and Blue Ridge terranes to the southeast and the Valley and Ridge Province to the northwest. At a dominant period ofAuthorsFred Pollitz, Walter D. Mooney - Software