The Research Program of ``Next Generation of Ground-Motion Attenuaton Models''

The program of "Next Generation of ground-motion Attenuation models" (NGA) is a partnered research program between the PEER-Lifelines program (PEER-LL), U.S. Geological Survey (USGS), and Southern California Earthquake Center (SCEC). The goal of the NGA program is the development of several scientifically based attenuation relationships having less variability and more reliable predictions of ground motions for use in engineering design practice. The current phase of the NGA program focuses on the use of empirical ground-motion data, with theoretically simulated ground motions guiding the selection of functional forms and the extrapolation outside the region of empirical data. Five developer teams were invited to participate in the concurrent development of attenuation models. In support of these developers, the NGA program also undertakes a series of closely coordinated seismological and geotechnical research projects. Six working groups are organized to conduct, review, and evaluate these research results. Members of the six working groups cover diverse expertise in strong-motion record processing, earthquake source/path effects, site classification and site response, and statistical analysis. Highlights of the NGA program and selected achievements are presented in this paper.