A spatial correlation model of peak ground acceleration and response spectra based on data of the Istanbul Earthquake Rapid Response and Early Warning System

• Published in: Soil dynamics and earthquake engineering (1984) 2016-06, Vol.85, p.166-178
• Main Authors: Wagener, Thomas, Goda, Katsuichiro, Erdik, Mustafa, Daniell, James, Wenzel, Friedemann
• Format: Article
• Language: English
• Subjects: Acceleration; Computer simulation; Correlation; Earthquake construction; Earthquake Loss; Earthquakes; Ground motion; Grounds; Istanbul Rapid Response and Early Warning System; Seismic phenomena; Spatial correlation
• ISSN: 0267-7261; 1879-341X
• DOI: 10.1016/j.soildyn.2016.03.016

Ground motion intensity measures such as the peak ground acceleration (PGA) and the pseudo-spectral acceleration (PSA) at two sites due to the same seismic event are correlated. The spatial correlation needs to be considered when modeling ground-motion fields for seismic loss assessments, since it can have a significant influence on the statistical moments and probability distribution of aggregated seismic loss of a building portfolio. Empirical models of spatial correlation of ground motion intensity measures exist only for a few seismic regions in the world such as Japan, Taiwan and California, since for this purpose a dense observation network of earthquake ground motion is required. The Istanbul Earthquake Rapid Response and Early Warning System (IERREWS) provides one such dense array with station spacing of typically 2km in the urban area of Istanbul. Based on the records of eight small to moderate (Mw3.5–Mw5.1) events, which occurred since 2003 in the Marmara region, we establish a model of intra-event spatial correlation for PGA and PSA up to the natural period of 1.0s. The results indicate that the correlation coefficients of PGA and short-period PSA decay rapidly with increasing interstation distance, resulting in correlation lengths of approximately 3–4km, while correlation lengths at longer natural periods (above 0.5s) exceed 6km. Finally, we implement the correlation model in a Monte Carlo simulation to evaluate economic loss in Istanbul's district Zeytinburnu due to a Mw7.2 scenario earthquake. •Empirical model of ground motion correlation for Istanbul.•Small correlation lengths from a dense accelerometer array.•Demonstration of relevance for loss assessment.