Developments in Seismic Hazard Assessment in the Central and Eastern United States

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This webinar will provide an overview of developments in seismic hazard assessment in the Central and Eastern United States (CEUS), with a focus on their applicability to dam sites. The course will begin with a description of the available approaches, seismic source models, and ground motion models used to evaluate seismic hazard in the CEUS, and how these approaches, models, and the resulting ground motions differ from those in the Western United States (WUS). Illustrative examples will be provided to demonstrate the different options available for evaluating seismic hazard at a dam site in the CEUS, including the use of publicly available regional models and site-specific seismic hazard assessments. Available methods for accounting for local site effects will be presented, including developments in simplified site adjustment models and site-specific site response analysis. The webinar will conclude with a discussion of the different ways seismic hazard assessments are used in dam safety evaluations, ranging from a single evaluation level tied to a deterministic earthquake scenario to use of the entire ground motion hazard curve in a risk analysis.

Learning Objectives
1. Understand key differences between seismic hazard in the WUS and CEUS
2. Understand the options available for estimating seismic hazard in the CEUS ranging from the USGS unified seismic hazard tool to site-specific hazard analysis
3. Understand the methods available for accounting for local site effects ranging from simplified site adjustment factors to site-specific site response analysis
4. Review of how seismic hazard analyses are used in dam safety evaluations, i.e., selection of the deterministic “MCE,” selection of a single probabilistic return period, or use of the entire hazard curve in a risk analysis

Glenn J. Rix, Ph.D., P.E.

Geosyntec Consultants, Inc.

Glenn J. Rix is a senior principal geotechnical engineer based in Georgia with more than 30 years of experience focused on the areas of geotechnical earthquake engineering and engineering seismology. His practice includes seismic hazard and risk assessment and mitigation for civil infrastructure. Glenn joined the firm following a 23-year career as a professor in the School of Civil and Environmental Engineering at the Georgia Institute of Technology. Since joining Geosyntec, Glenn has performed seismic hazard and risk analyses, liquefaction triggering evaluations, site response analyses, and seismic stability and deformation analyses for embankment and concrete dams, coal combustion residual (CCR) storage facilities, municipal and hazardous waste landfills, liquefied natural gas facilities, and highway bridges. He has also served as an external peer reviewer for seismic hazard analyses for nuclear power plants and provided litigation support for numerous cases related to the effects of blasting- and construction-induced ground vibrations on structures. Glenn is a leading authority on in-situ seismic methods and is a co-author of Surface Wave Methods for Near-Surface Site Characterization and the forthcoming American Association of State Highway and Transportation Officials (AASHTO) Manual on Subsurface Investigations.

Christie Hale

Geosyntec Consultants, Inc.

Christie Hale is a seismic hazard analyst involved in seismic safety assessment projects. Her technical experience includes deterministic and probabilistic seismic hazard analysis, deaggregation analysis, target spectrum development, and time history selection and modification. Dr. Hale also has experience in PSHA code development, testing, and verification, and is a key contributor to the PSHA computer program HAZ45. Prior to joining Geosyntec, she led the PSHA Code Verification project at the Pacific Earthquake Engineering Research Center, where her ability to understand how different modeling approaches impact the resulting seismic hazard curves was instrumental in helping participants troubleshoot their codes and ultimately reach consensus answers.