From Ergodic to Region- and Site-Specific Probabilistic Seismic Hazard Assessment: Method Development and Application at European and Middle Eastern Sites. 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: 1433
• Page End: 1453
• Publication Date: 2017-11
• Subjects: Earthquake engineering -- Periodicals; Earthquake engineering; Periodicals; 624.1762
• DOI: 10.1193/081016eqs130m
• Languages: English
• ISSNs: 8755-2930

Abstract

The increasing numbers of recordings at individual sites allows quantification of empirical linear site-response adjustment factors ( δS 2 S s ) from the ground motion prediction equation (GMPE) residuals. The δS 2 S s are then used to linearly scale the ergodic GMPE predictions to obtain site-specific ground motion predictions in a partially non-ergodic Probabilistic Seismic Hazard Assessment (PSHA). To address key statistical and conceptual issues in the current practice, we introduce a novel empirical region- and site-specific PSHA methodology wherein, (1) site-to-site variability ( φ S 2 S ) is first estimated as a random-variance in a mixed-effects GMPE regression, (2) δS 2 S s at new sites with strong motion are estimated using the a priori φ S 2 S, and (3) the GMPE site-specific single-site aleatory variability σ ss, s is replaced with a generic site-corrected aleatory variability σ 0 . Comparison of region- and site-specific hazard curves from our method against the traditional ergodic estimates at 225 sites in Europe and Middle East shows an approximate 50% difference in predicted ground motions over a range of hazard levels—a strong motivation to increase seismological monitoring of critical facilities and enrich regional ground motion data sets.