Site-Corrected Magnitude- and Region-Dependent Correlations of Horizontal Peak Spectral Amplitudes. Issue 4 (November 2017)

• Record Type: Journal Article
• Authors: Kotha, Sreeram Reddy; Bindi, Dino; Cotton, Fabrice
• Is Part Of: Earthquake spectra. Volume 33:Issue 4(2017)
• Page Start: 1415
• Page End: 1432
• Publication Date: 2017-11
• Subjects: Earthquake engineering -- Periodicals; Earthquake engineering; Periodicals; 624.1762
• DOI: 10.1193/091416eqs150m
• Languages: English
• ISSNs: 8755-2930

Abstract

Empirical correlations of horizontal peak spectral amplitudes (PSA) are modeled using the total-residuals obtained in a ground motion prediction equation (GMPE) regression. Recent GMPEs moved toward partially non-ergodic region- and site-specific predictions, while the residual correlation models remained largely ergodic. Using mixed-effects regression, we decompose the total-residuals of a pan-European GMPE into between-event, between-site, and event-and-site corrected residuals to investigate the ergodicity in empirical PSA correlations. We first observed that the between-event correlations are magnitude-dependent, partially due to the differences in source spectra, and influence of stress-drop parameter on small and large events. Next, removing the between-site residuals from within-event residuals yields the event-and-site corrected residuals which are found to be region-dependent, possibly due to the regional differences in distance-decay of short period PSAs. Using our site-corrected magnitude- and region-dependent correlations, and the between-site residuals as empirical site-specific ground motion adjustments, we compute partially non-ergodic conditional mean spectra at four well-recorded sites in Europe and Middle Eastern regions.09_EERI_33_4_Suppl_ES1_Online.xlsx