On the Ground Motions Spatial Correlation for Vrancea Intermediate-Depth Earthquakes
The spatial correlation of ground motions is a subject extensively analysed in the literature, with many studies obtaining spatial correlation models for different datasets, using multiple ground motion prediction equations for various ground motion parameters, being a necessary tool in assessing the seismic risk of building portfolios or spatially distributed systems. A subject tackled mostly for shallow earthquakes datasets, in recent months, two studies considering a database consisting of strong ground motions generated by earthquakes originating from Vrancea intermediate-depth seismic source have been developed. The differences between the two studies consist of the approach in obtaining the correlation model, directly evaluating the correlation coefficients and using the semivariogram approach. A comparison of the two studies is made, resulting in different decay ratios for the same ground motion parameter, the main reasons being the restrains encountered in the first methodology and the subtraction of some ground motion records in the second study. An investigation regarding the influence of the dataset is performed by developing a correlation model for an adjusted dataset using the direct approach. Comparisons with other available models are performed, revealing higher correlation values and more gradual decays for the two studies discussed here, which is mainly caused by the different seismo-tectonic context of the Vrancea intermediate-depth source.
KeywordCorrelation coefficient Models Semivariogram Comparison
The results are obtained within the CoBPEE (Community Based Performance Earthquake Engineering) research project, financed by the Romanian National Authority for Scientific Research and Innovation, CNCS—UEFISCDI, project number PN-II-RU-TE-2014-4-0697. This support is gratefully acknowledged.
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