UCLA

We present the development of ground-motion models (GMMs) to predict 5% damped pseudo-spectral accelerations (PSA) and effective amplitude spectra (EAS) as part of the NGA-West3 project. Our approach utilizes the project dataset and shared functional forms for the PSA and EAS models, which are being developed in a coordinated manner to ensure internal consistency. This is different from other approaches that focus mainly on EAS models and then convert them to PSA using random vibration theory and duration models. Both our EAS and PSA models are conditioned on the same predictor variables and include broad regional adjustments to capture tectonic variability. The PSA model is being developed through a traditional period-by-period mixed-effects framework, whereas the EAS model utilizes a seismologically-based source parameterization and frequency-dependent path and site models. Ongoing work aims to refine regionalization, anelastic attenuation, and site response models.