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 About the CompanyJim HumphreyVice President Mr. Humphrey is a founding principal and senior scientist at Lahontan GeoScience. He specializes in environmental geology and seismic hazard assessment. Mr. Humphrey received his Bachelor of Science Degree in Geology in 1980 from the University of California at Davis. 1980, Mr. Humphrey joined Woodward-Clyde Consultants, an internationally known engineering consulting firm. In 1989, Mr. Humphrey returned to graduate school at the University of Nevada, Reno (UNR), to study site amplification effects of large earthquakes. His research contributions include over 25 papers and abstracts published in professional journals. Mr. Humphrey left UNR in 1994 to become a founding principal at Lahontan GeoScience, Inc. Mr. Humphrey has twenty years of professional experience in the fields of engineering seismology and seismic hazard analysis. He specializes in seismic data acquisition, regional and local seismicity evaluation, site-specific ground motion estimation, and analysis of induced seismicity (both reservoir and mining induced). His project experience typically involves integration of geologic and seismologic data to assess seismic hazard and development of design ground motions for site-specific dynamic analysis. Recently Lahontan GeoScience and William Lettis and Associates teamed to evaluate seismic hazards for the Almanor and Butt Valley dams in the northern Sierra Nevada for Pacific Gas & Electric. Mr. Humphrey integrated the historical and instrumental earthquake data to compile a seismicity catalog for the northern Sierra Nevada and northeastern Sacramento Valley, and evaluated the occurrence, style and rate of seismic activity in the study region. Mr. Humphrey has extensively investigated the seismologic characteristics of large subduction zone earthquakes including the 1985 M 8.1 Michoacan, Mexico, and the 1985 M 8 Valparaiso, Chile, earthquakes to determine factors influencing site-specific seismic response. Near-field ground motions were simulated using a stochastic, random vibration theory based, finite-source model which incorporates the effects of dynamic and geometrical properties of source rupture, crustal wave propagation, and site-specific response. These projects provided a way to validate numerical models of earthquake source and seismic energy propagation to enable estimation of ground motion from a postulated Cascadia subduction zone earthquake in the seismic hazard evaluation for several critical structures in Oregon, including the Trojan nuclear power plant. Mr. Humphrey has been involved in several projects to evaluate induced seismicity either due to reservoir loading or mining activities. These projects usually involve data acquisition on site, analysis of seismic waveforms to differentiate between tectonic and induced or triggered earthquakes, and determining the impact of a maximum event.
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