NGA‐West2 Research Project

The NGA‐West2 project is a large multidisciplinary, multi‐year research program on the Next Generation Attenuation (NGA) models for shallow crustal earthquakes in active tectonic regions. The research project has been coordinated by the Pacific Earthquake Engineering Research Center (PEER), with extensive technical interactions among many individuals and organizations. NGA‐West2 addresses several key issues in ground‐motion seismic hazard, including updating the NGA database for a magnitude range of 3.0–7.9; updating NGA ground‐motion prediction equations (GMPEs) for the “average” horizontal component; scaling response spectra for damping values other than 5%; quantifying the effects of directivity and directionality for horizontal ground motion; resolving discrepancies between the NGA and the National Earthquake Hazards Reduction Program (NEHRP) site amplification factors; analysis of epistemic uncertainty for NGA GMPEs; and developing GMPEs for vertical ground motion. This paper presents an overview of the NGA‐West2 research program and its subprojects.