Empirical correlations between ground‐motion intensity measures (IMs) are essential for engineering applications, including conditional ground‐motion selection and vector‐valued probabilistic seismic hazard analysis (VPSHA). Although previous research has thoroughly investigated interperiod correlations of response spectral ordinates and relationships between nonspectral IMs and pseudo‐spectral acceleration (PSA), the connections between engineering IMs and Fourier spectral ordinates remain inadequately characterized from an engineering seismology standpoint. This investigation establishes comprehensive empirical correlations between PSAs, Arias intensity (AI), and cumulative absolute velocity (CAV) with Fourier spectral amplitudes utilizing the NGA‐West2 database. The linear correlations are presented using total residuals of the IMs with respect to established ground‐motion models from Abrahamson et al. (2014), Bora et al. (2019), Afshari and Stewart (2016), and Campbell and Bozorgnia (2019). A partial correlation methodology isolates frequency‐dependent relationships. The results confirm earlier observations by Bora et al. (2016) and identify specific frequency ranges controlling individual IMs. Peak ground acceleration (PGA) and peak ground velocity (PGV) are predominantly influenced by higher‐frequency content, with distinct frequency ranges characterizing each parameter. Conversely, AI and CAV exhibit sensitivity across a broader, overlapping frequency band (1–3 Hz). Scenario‐dependent analysis through magnitude binning reveals systematic correlation variations, which essentially explain the regional differences in IM‐Fourier amplitude relationships. These findings illuminate the physical foundation of engineering IMs and hold substantial implications for host‐to‐target adjustments of GMMs, next‐generation GMM development, physics‐based ground‐motion simulation, and understanding of IM correlations in existing literature. The work successfully connects seismological and engineering ground‐motion characterizations.
Sanjay Singh Bora (Sun,) studied this question.