UCLA

The NGA-Subduction Project is a multi-year, multidisciplinary project with the goal of developing a ground motion database and ground motion models for global subduction zone earthquakes including those in Japan, Taiwan, Cascadia, Alaska, New Zealand, South America, and Central America. Our ground motion model development is currently at the stage of identifying regional trends in path terms. We use a combination of data inspection and regression techniques to distinguish path effects in the data, including differences between interface and inslab events, forearc/back-arc effects, regional effects, and azimuthal effects. Our approach to model development is to first develop a path model capturing these effects, then to investigate source and site effects. The parameterization of functional form is guided in part by the scaling expected by a generic equivalent point-source stochastic model. We expect regionalization in path and will investigate further regionalization in site response and in overall model bias.