Nga-subduction research program

This paper provides an overview of NGA-Sub, a large multidisciplinary community-based research initiative to develop a comprehensive ground-motion database and multiple ground-motion models (GMMs) for subduction events. In the NGA-Sub project, we developed a database of ground motions recorded in worldwide subduction events. The database includes the processed recordings and supporting source, path, and site metadata from Japan, Taiwan, the US Pacific Northwest, Alaska, Latin America (including Mexico, Peru and Chile), and New Zealand. The NGASub database includes 1,570 events with moment magnitudes ranging from 4.0 to 9.1. The subduction events are classified as interface, intraslab, or outer-rise events. The NGA-Sub ground-motion database has over 214,000 individual ground-motion components. This is by far the largest ground-motion database that we have ever developed in any NGA project. Pseudo-spectral acceleration as well as Fourier amplitude spectra for frequencies from 0.1 to 100 Hz have been included in the database. Multiple GMMs are developed using the empirical ground-motion database and the supporting ground-motion simulations. The scope of the NGA-Sub GMMs is to develop models for horizontal components of ground motion for 5% damped pseudo-acceleration response spectra for period range of 0.01 to 10 sec. Following the tradition of previous NGA projects, the GMM modeling teams as well as database developers have had continuous technical interactions which resulted in a higher quality of the final products than each researcher or oneteam group could achieve individually. An overview of the NGA-Sub project is presented in this paper.,.