Spatial Correlation of Acceleration Spectral Ordinates from European Data

Spatial correlation of spectral acceleration (Sa) is required in modelling hazard for risk assessment of spatially distributed systems. The estimation of an appropriate correlation model is still a research task in earthquake engineering, because of several issues related to: data, statistical approaches and estimation tools, and tests to evaluate the estimated models. This paper focuses on the evaluation of the spatial correlation of Sa using records belongs the European Strong motion Database (ESD). The estimation has been performed on multiple earthquakes, considering a ground motion prediction equations (GMPE) fitted to the same records. Results show that the decay rate of correlation, as a function of inter-site distance, tends to increase with structural period. Based on that, a simple linear relationship for the correlation length as a function of structural period is derived, discussed, and compared with previous research on the same topic.