Paul A Bedrosian
Paul is an expert in the development and application of electromagnetic geophysical methods to framework tectonics, resource assessment, natural hazards and fundamental Earth processes. His work has investigated seismic variability along the San Andreas Fault, tectonics of the Pacific Northwest and Upper Midwest, and the structure of Mount St. Helens. His current research is on regional-scale mine
Research Interests
- Structure and evolution of active and fossil tectonic margins
- Geophysical imaging of hydrothermal and magmatic systems
- Joint interpretation of coincident geophysical data sets
- Advanced processing and modeling techniques for imaging earth structure
Professional Experience
2008-present, Research Geophysicist, U.S. Geological Survey, Denver, Colorado
2005-2007, Mendenhall Fellow, U.S Geological Survey, Denver, Colorado
2002-2004, Humboldt Fellow, GeoForschungsZentrum, Potsdam Germany
1998-2002, Research Assistant, University of Washington, Seattle, Washington
Education and Certifications
Ph.D. Physics, University of Washington, 2002
M.S. Physics, University of Washington, 1998
B.S. Physics, University Of Minnesota, 1996
B.S. Chemistry, University of Minnesota, 1996
Affiliations and Memberships*
2010-present, Summer of Applied Geophysical Experience (faculty)
2018-present, Earth, Planets and Space Journal (editor)
American Geophysical Union
Geological Society of America
Science and Products
Evaluation of geophysical techniques for the detection of paleochannels in the Oakland area of eastern Nebraska as part of the Eastern Nebraska Water Resource Assessment
Geophysical investigations of geology and structure at the Martis Creek Dam, Truckee, California
Geophysical, geochemical, and mineralogical data from the Pebble Cu-Au-Mo porphyry deposit area, southwest Alaska: Contributions to assessment techniques for concealed mineral resources
Correlation between deep fluids, tremor and creep along the central San Andreas fault
Shallow lithological structure across the Dead Sea Transform derived from geophysical experiments
Hydrostratigraphic interpretation of test-hole and geophysical data, Upper Loup River Basin, Nebraska, 2008-10
Using airborne geophysical surveys to improve groundwater resource management models
Anatomy of the dead sea transform from lithospheric to microscopic scale
Joint inversion for Vp, Vs, and Vp/Vs at SAFOD, Parkfield, California
A deep crustal fluid channel into the San Andreas Fault system near Parkfield, California
Lithology-derived structure classification from the joint interpretation of magnetotelluric and seismic models
MT+, integrating magnetotellurics to determine earth structure, physical state, and processes
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
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Filter Total Items: 76
Evaluation of geophysical techniques for the detection of paleochannels in the Oakland area of eastern Nebraska as part of the Eastern Nebraska Water Resource Assessment
Over the winter and spring of 2009, the U.S. Geological Survey conducted a general assessment of the capabilities of several geophysical tools to delineate buried paleochannel aquifers in the glacial terrain of eastern Nebraska. Mapping these paleochannels is an important objective for the Eastern Nebraska Water Resources Assessment group. Previous attempts at mapping these channels included a helAuthorsJared D. Abraham, Paul A. Bedrosian, Theodore H. Asch, Lyndsay B. Ball, James C. Cannia, Jeffery D. Phillips, Susan LackeyGeophysical investigations of geology and structure at the Martis Creek Dam, Truckee, California
A recent evaluation of Martis Creek Dam highlighted the potential for dam failure due to either seepage or an earthquake on nearby faults. In 1972, the U.S. Army Corps of Engineers constructed this earthen dam, located within the Truckee Basin to the north of Lake Tahoe, CA for water storage and flood control. Past attempts to raise the level of the Martis Creek Reservoir to its design level haveAuthorsP. A. Bedrosian, B.L. Burton, M.H. Powers, B. J. Minsley, J. D. Phillips, L. E. HunterGeophysical, geochemical, and mineralogical data from the Pebble Cu-Au-Mo porphyry deposit area, southwest Alaska: Contributions to assessment techniques for concealed mineral resources
In 2007, the U.S. Geological Survey began a multidisciplinary study in southwest Alaska to investigate the setting and detectability of mineral deposits in concealed volcanic and glacial terranes. The study area hosts the world-class Pebble porphyry Cu-Au-Mo deposit, and through collaboration with the Pebble Limited Partnership, a range of geophysical and geochemical investigations was carried outAuthorsE. D. Anderson, S. M. Smith, S. A. Giles, Matthew Granitto, R. G. Eppinger, P. A. Bedrosian, A. K. Shah, K. D. Kelley, D. L. Fey, B. J. Minsley, P. J. BrownCorrelation between deep fluids, tremor and creep along the central San Andreas fault
The seismicity pattern along the San Andreas fault near Parkfield and Cholame, California, varies distinctly over a length of only fifty kilometres. Within the brittle crust, the presence of frictionally weak minerals, fault-weakening high fluid pressures and chemical weakening are considered possible causes of an anomalously weak fault northwest of Parkfield. Non-volcanic tremor from lower-crustaAuthorsM. Becken, O. Ritter, P. A. Bedrosian, U. WeckmannShallow lithological structure across the Dead Sea Transform derived from geophysical experiments
In the framework of the DEad SEa Rift Transect (DESERT) project a 150 km magnetotelluric profile consisting of 154 sites was carried out across the Dead Sea Transform. The resistivity model presented shows conductive structures in the western section of the study area terminating abruptly at the Arava Fault. For a more detailed analysis we performed a joint interpretation of the resistivity modelAuthorsJ. Stankiewicz, G. Munoz, O. Ritter, Paul A. Bedrosian, T. Ryberg, U. Weckmann, M. WeberHydrostratigraphic interpretation of test-hole and geophysical data, Upper Loup River Basin, Nebraska, 2008-10
Nebraska's Upper Loup Natural Resources District is currently (2011) participating in the Elkhorn-Loup Model to understand the effect of various groundwater-management scenarios on surface-water resources. During Phase 1 of the Elkhorn-Loup Model, a lack of subsurface geological information in the Upper Loup Natural Resources District, hereafter referred to as the upper Loup study area, was identiAuthorsChristopher M. Hobza, Theodore H. Asch, Paul A. BedrosianUsing airborne geophysical surveys to improve groundwater resource management models
Increasingly, groundwater management requires more accurate hydrogeologic frameworks for groundwater models. These complex issues have created the demand for innovative approaches to data collection. In complicated terrains, groundwater modelers benefit from continuous high‐resolution geologic maps and their related hydrogeologic‐parameter estimates. The USGS and its partners have collaborated toAuthorsJared D. Abraham, James C. Cannia, Steven M. Peterson, Bruce D. Smith, Burke J. Minsley, Paul A. BedrosianAnatomy of the dead sea transform from lithospheric to microscopic scale
Fault zones are the locations where motion of tectonic plates, often associated with earthquakes, is accommodated. Despite a rapid increase in the understanding of faults in the last decades, our knowledge of their geometry, petrophysical properties, and controlling processes remains incomplete. The central questions addressed here in our study of the Dead Sea Transform (DST) in the Middle East arAuthorsM. Weber, K. Abu-Ayyash, A. Abueladas, A. Agnon, Z. Alasonati-Tasarova, H. Al-Zubi, A. Babeyko, Y. Bartov, K. Bauer, M. Becken, P. A. Bedrosian, Z. Ben-Avraham, G. Bock, M. Bohnhoff, J. Bribach, P. Dulski, J. Ebbing, R. El-Kelani, A. Forster, H.-J. Forster, U. Frieslander, Z. Garfunkel, H.J. Goetze, V. Haak, C. Haberland, M. Hassouneh, S. Helwig, A. Hofstetter, A. Hoffmann-Rotrie, K.H. Jackel, C. Janssen, D. Jaser, D. Kesten, M. Khatib, R. Kind, O. Koch, I. Koulakov, Gabi Laske, N. Maercklin, R. Masarweh, A. Masri, A. Matar, J. Mechie, N. Meqbel, B. Plessen, P. Moller, A. Mohsen, R. Oberhansli, S. Oreshin, A. Petrunin, I. Qabbani, I. Rabba, O. Ritter, R.L. Romer, G. Rumpker, M. Rybakov, T. Ryberg, J. Saul, F. Scherbaum, S. Schmidt, A. Schulze, S.V. Sobolev, M. Stiller, D. Stromeyer, K. Tarawneh, C. Trela, U. Weckmann, U. Wetzel, K. WylegallaJoint inversion for Vp, Vs, and Vp/Vs at SAFOD, Parkfield, California
We refined the three-dimensional (3-D) Vp, Vs and Vp/Vs models around the San Andreas Fault Observatory at Depth (SAFOD) site using a new double-difference (DD) seismic tomography code (tomoDDPS) that simultaneously solves for earthquake locations and all three velocity models using both absolute and differential P, S, and S-P times. This new method is able to provide a more robust Vp/Vs model thaAuthorsH. Zhang, C. Thurber, P. BedrosianA deep crustal fluid channel into the San Andreas Fault system near Parkfield, California
Magnetotelluric (MT) data from 66 sites along a 45-km-long profile across the San Andreas Fault (SAF) were inverted to obtain the 2-D electrical resistivity structure of the crust near the San Andreas Fault Observatory at Depth (SAFOD). The most intriguing feature of the resistivity model is a steeply dipping upper crustal high-conductivity zone flanking the seismically defined SAF to the NE, thatAuthorsM. Becken, O. Ritter, S. K. Park, P. A. Bedrosian, U. Weckmann, M. WeberLithology-derived structure classification from the joint interpretation of magnetotelluric and seismic models
Magnetotelluric and seismic methods provide complementary information about the resistivity and velocity structure of the subsurface on similar scales and resolutions. No global relation, however, exists between these parameters, and correlations are often valid for only a limited target area. Independently derived inverse models from these methods can be combined using a classification approach tAuthorsP. A. Bedrosian, N. Maercklin, U. Weckmann, Y. Bartov, T. Ryberg, O. RitterMT+, integrating magnetotellurics to determine earth structure, physical state, and processes
As one of the few deep-earth imaging techniques, magnetotellurics provides information on both the structure and physical state of the crust and upper mantle. Magnetotellurics is sensitive to electrical conductivity, which varies within the earth by many orders of magnitude and is modified by a range of earth processes. As with all geophysical techniques, magnetotellurics has a non-unique inverseAuthorsP. A. BedrosianNon-USGS Publications**
P.A. Bedrosian, M.J. Unsworth, G.D. Egbert and C.H. Thurber. 2004. Geophysical images of the creeping San Andreas Fault: Implications for the role of crustal fluids in the earthquake process, Tectonophys., 385(1-4), doi:10.1016/j.tecto.2004.02.010.M.J. Unsworth and P.A. Bedrosian. 2004. Electrical resistivity structure at the SAFOD site from magnetotelluric exploration, Geophys. Res. Lett., 31(12), doi:10.1029/2003GL019045.M.J. Unsworth and P.A. Bedrosian. 2004. On the geoelectric structure of major strike-slip faults and shear zones., Earth, Planets and Space, 56, 1177–1184, doi:10.1186/BF03353337.M.J. Unsworth, W. Wenbo, A. G. Jones, S. Li, P.A. Bedrosian, J. Booker, J. Sheng, D. Ming and T. Handong. 2004. Crustal and upper mantle structure of Northern Tibet imaged with magnetotelluric data, J. Geophys. Res., 109, doi:10.1029/2002JB002305.P.A. Bedrosian, M.J. Unsworth and G.D. Egbert. 2002. Magnetotelluric imaging of the creeping segment of the San Andreas Fault near Hollister, Geophys. Res. Lett., 29(11), 1506, doi:10.1029/2001GL014119.M. Unsworth, O.C. Enriquez, S. Belmonte, J. Arzate and P.A. Bedrosian. 2002. Crustal structure of the Chicxulub Impact Crater imaged with magnetotelluric exploration, Geophys. Res. Lett., 29(16), 1788, doi:10.1029/2002GL014998.P.A. Bedrosian, M.J. Unsworth and F. Wang. 2001. Structure of the Altyn Tagh Fault and Daxue Shan from magnetotelluric surveys: Implications for faulting associated with the rise of the Tibetan Plateau, Tectonics, 20, 474-486, doi:10.1029/2000TC001215.W. Wenbo, M. Unsworth, A. Jones, J. Booker, H. Tan, D. Nelson, L. Chen, S. Li, K. Solon, P.A. Bedrosian, S. Jin, M. Deng, J. Ledo, D. Kay and B. Roberts. 2001. Widespread fluids in the Tibetan Crust, Science, 292(5517), 716-718, doi:10.1126/science.1010580.M. Unsworth, P.A. Bedrosian, M. Eisel, G. Egbert and W. Siripunvaraporn. 2000. Along-strike variations in the electrical structure of the San Andreas Fault at Parkfield, California, Geophys. Res. Lett., 27(18), 3021-3024, doi:10.1029/2000GL011476.**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
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*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government