New PEER Report 2015/08: “NGA-East: Adjustments to Median Ground-Motion Models for Central and Eastern North America”

PEER has just published Report No. 2015/08 titled “NGA-East: Adjustments to Median Ground-Motion Models for Central and Eastern North America” as a new addition to the PEER Report Series.

Visit the PEER publications page to download a free color pdf of the document.


This report documents a series of adjustments developed for the median ground-motion models (GMMs) developed as part of the Next Generation Attenuation for Central and Eastern North America (CENA) project (NGA-East). NGA-East is a multi-disciplinary research project coordinated by the Pacific Earthquake Engineering Research Center (PEER) that involves a large number of participating junior and senior researchers, practitioners, and end-users. Various organizations have provided technical input to the project from academia, industry, and government agencies. The objective of NGA-East is to develop a new ground motion characterization (GMC) model for the CENA region. The tectonic region of interest reaches across into Canada; thus, the term CENA instead of CEUS is used. The GMC consists in a set of new models (GMMs, a.k.a. GMPEs) for median horizontal ground motions, a set of standard deviation models, and their associated weights in logic trees for use in probabilistic seismic hazard analyses (PSHA).

The current report documents a set of adjustments to median GMMs that are necessary so that NGA-East (1) is applicable to rupture distances in the range from 0 to 1500 km; (2) allows source depth effects to be incorporated; and (3) is applicable to the vast CENA region to include the Gulf Coast and the Mississippi Embayment. The three corresponding adjustment models are documented herein. This report can be considered as a supplemental report to the original NGA-East PEER report on median GMMs [PEER 2015].