Empirical ground-motion models (GMMs) and associated correlations for cumulative absolute velocity, Arias intensity, and significant durations calibrated on Iranian strong motion database

This study presents empirical ground-motion models (GMMs) for estimating Arias intensity (IA), cumulative absolute velocity (CAV) and significant ground-motion duration (D5–75 and D5–95), calibrated on Iranian strong motion database. The dataset consists of 1749 (with two horizontal components) acceleration motion time-series originated from 566 events with moment magnitude (Mw) 3–7.5 range and recorded at 338 stations in the distances range up to 200 km. Common functional forms were adopted for all four models to facilitate easy comparison of derived model parameters and model predictions. Residual distributions and their unbiased variation with predictor variables Mw, hypocentral distance (Rhypo), time-averaged shear-wave velocity in the top 30 m (VS30) indicated robustness of the derived models. This study also examines residual correlations between different pairs of ground-motion intensity measures (GMIMs). The correlations were analysed separately for between-event (δBe\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\delta B}_{e}$$\end{document}) and within-event (δWSes\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\delta WS}_{es}$$\end{document}) component of the residuals. The correlation of δBe\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\delta B}_{e}$$\end{document} between: (1) IA and the two duration measures (D5–75 and D5–95), (2) CAV and the two duration measures were found depending upon the event magnitude (strongest for Mw > 6). Similarly, the correlation of δWSes\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\delta WS}_{es}$$\end{document} between: (1) IA and the two duration measures, (2) CAV and the two duration measures were observed depending upon source-to-site distance (strongest for Rhypo < 50 km). Furthermore, a relatively stronger negative correlation of δWSes\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\delta WS}_{es}$$\end{document} was observed between CAV and station-specific attenuation parameter (κ0) (mainly at softer soil sites) in comparison to that between IA and κ0.