The 2023 William B. Joyner Lecture
www.seismosoc.org/awards/jack...
Supporting papers and software related to this lecture are available at www.jackwbaker.com/joyner.htm
Abstract:
The amplitude of ground shaking during an earthquake varies spatially, due to location-to-location differences in source features, wave propagation, and site effects. These variations have important impacts on infrastructure systems and other distributed assets. This presentation will provide an overview of efforts to quantify spatial correlations in amplitudes, via observations from past earthquakes and numerical simulations. Regional risk analysis results will be presented to demonstrate the potential role of spatial correlations on impacts to the built environment. Traditional techniques for fitting empirical correlation models will be discussed, followed by a proposal for new techniques to account for soil conditions and other site-specific effects. Prospects for future opportunities in this field will also be addressed, including the role of numerical simulations and advanced risk assessment.
Acknowledgments:
Financial support for this work from the U.S. Geological Survey, National Science Foundation, Southern California Earthquake Center, and Pacific Earthquake Engineering Research Center is gratefully acknowledged.
I thank the many inspiring students who led the work described here. Nirmal Jayaram laid the initial foundation for our group's work. Nirmal and Mahalia Miller quantified the importance of this topic for regional risk analysis, and developed numerical algorithms to speed risk computations. Christophe Loth and Maryia Markhvida developed elegant techniques for extending correlation models to quantify cross-correlations across intensity metrics. Yilin Chen did our group's first work to evaluate nonstationary correlation models, and to develop approaches for detecting and predicting nonstationarities. And Lukas Bodenmann is responsible for several innovations to develop and evaluate correlation models with multiple predictor variables.
I am also grateful to many collaborators who supported this work. Brendon Bradley was instrumental in evaluating and interpreting New Zealand ground motion data that provided insights about nonstationarity. Bruce Worden, Eric Thompson, Nico Luco, and David Wald were wonderful partners as they deployed some of these concepts in USGS ShakeMaps. Rob Graves was gracious and supportive in helping with evaluations of CyberShake ground motion simulations. Božidar Stojadinović sent Lukas Bodenmann to Stanford, triggering many of the recent developments, and supported the completion and publication of his work.
Thanks to Allin Cornell for training me in this field, and involving me as a contributor to his 2005 Joyner Lecture. He set me on a professional path that I continue down today.
Finally, thanks to Bill Joyner for his commitment to exchanging information at the interface of earthquake science and engineering. Opportunities at this interface have provided me with an incredibly rewarding career.