This study aims to develop correlation models for ground-motion intensity measures based on the Turkish strong-motion data. The intensity measures under examination are horizontal spectral accelerations (SAs) with periods spanning from 0.01 to 10 s, in addition to peak ground acceleration, peak ground velocity, and significant duration. The investigation focuses on the dependence of the developed correlation coefficient models on the definitions of intensity measures. The examination of the Turkish strong-motion database revealed that the correlations in SA are mainly unaffected by the method chosen to define SA in multicomponent ground-motion records. Furthermore, an evaluation is conducted regarding the potential ergodicity dependence within the correlations of ground-motion intensity measures. Specifically, the total residuals derived from a recently developed local partially nonergodic ground-motion prediction model were categorized into between-event, event-and-site-corrected, and between-site residuals. The analysis revealed that the correlations among the between-event residuals exhibit a dependence on region and magnitude. Similarly, it was found that the correlations of event-and site-corrected residuals are influenced by region and source-to-site distance. By utilizing the site-corrected, region-specific correlations in conjunction with computed site-specific ground motions, partially nonergodic conditional mean spectra were developed for two well-monitored sites within the Marmara region.