Pacific Earthquake Engineering Research CenterNext Generation Attenuation Relationships for Western US


The NGA West program concluded in 2008. Subsequently two other NGA programs began in 2010, NGA East and NGA West 2. The NGA East Program is developing a new set of comprehensive & broadly accepted attenuation relationships for the Central and Eastern US.

The NGA West2 program is a followup to the original NGA program and will be investigating the modeling of directivity and directionality; verification of NGA-West models for recent small, moderate and large magnitude events; scaling of ground motion prediction equations (GMPE) for different levels of damping; development of GMPEs for vertical ground motion; treatment of epistemic uncertainty; and evaluation of soil amplification factors in NGA models versus NEHRP site factors. The NGA-West 2 program started on March 1, 2010 and will conclude in 30 months.