Ground-motion models for very-hard rock sites in eastern North America: An update

The ground‐motion models provided by me to the Next Generation Attenuation‐East (NGA‐East) project in 2015 have been updated by considering three additional Fourier spectra attenuation models and by conducting a mixed‐effect analysis of the residuals between the ground‐motion intensity measures computed from the attenuation models and the data from nine relatively well‐recorded events in eastern North America. On the basis of the period trends of the bias in the residuals and the distance trends of the residuals, I recommend the ground‐motion models developed for these attenuation models, with equal weights: the BCA10D model with 1/R geometrical spreading at all distances, and two modifications of the Atkinson and Boore (2014; referred as AB14) model, with 1/R spreading within 10 km, 1/R^1.3 spreading from 10 to 50 km, and 1/√R spreading beyond 50 km.