New conditional,scenario-based,and non-conditional cumulative absolute velocity models for subduction tectonic settings

Abstract

The PEER NGA-Sub ground-motion intensity measure database is used to develop new conditional ground-motion models (CGMMs), a set of scenario-based models, and non-conditional models to estimate the cumulative absolute velocity ( $\mathrm{CAV}$ ) of ground motions from subduction zone earthquakes. In the CGMMs, the median estimate of $\mathrm{CAV}$ is conditioned on the estimated peak ground acceleration ( $\mathrm{PGA}$ ), the time-averaged shear-wave velocity in the top 30 m of the soil ( $V_{S30}$ ), the earthquake magnitude ( $M_w$ ), and the spectral acceleration at the period of 1 s ( $\mathrm{PSA}(1.0\mathrm{s})$ ). Multiple scenario-based $\mathrm{CAV}$ models are developed by combining the CGMMs with pseudo-spectral acceleration ( $\mathrm{PSA}$ ) ground-motion models (GMMs) for $\mathrm{PGA}$ and $\mathrm{PSA}(1.0\mathrm{s})$ to directly estimate $\mathrm{CAV}$ given an earthquake scenario and site conditions. Scenario-based $\mathrm{CAV}$ models are capable of capturing the complex ground-motion effects (e.g. soil non-linearity and regionalization effects) included in their underlying $\mathrm{PGA}$ / $\mathrm{PSA}$ GMMs. This approach also ensures the consistency of the $\mathrm{CAV}$ estimates with a $\mathrm{PSA}$ design spectrum. In addition, two non-conditional $\mathrm{CAV}$ GMMs are developed using Bayesian hierarchical regressions. Finally, we present comparisons between the developed models. The comparisons show that if non-conditional GMMs are properly constrained, they are consistent with scenario-based GMMs. The $\mathrm{CAV}$ GMMs developed in this study advance the performance-based earthquake engineering practice in areas affected by subduction zone earthquakes.