Analysis of Uncertainty of Vs30 in Southern California
Mayo Thompson*, John N. Louie, Mahesh S. Dhar, Nevada Seismological Laboratory, Mackay School of Earth Sciences and Engineering, University of Nevada, Reno, Nevada, U.S.A.;
Aasha Pancha, Satish Pullammanappallil, Optim SDS, Reno, Nevada, U.S.A.;
Alan K. Yong, Earthquake Hazards Team, U.S. Geological Survey, Pasadena, California, U.S.A.
In the western U.S., the average shear-wave velocity in the upper 30 m (Vs30) is currently the most popular predictor of ground motions in probabilistic models that estimate earthquake hazards. Because the coverage of Vs30 measurements in southern California is sparse, researchers have proposed various methods to predict Vs30 where there are few direct
measurements. The predictions from these various proxies can differ greatly from direct measure-ments, reflecting various kinds of uncertainty. The epistemic uncertainty, when reported, is not enough to describe the difference. We seek to evaluate various first-order uncertainties of predictions based on publicly available direct measurements.