Regional Kappa Models on North Anatolian Fault Zone (Turkey) and Their Use in Ground Motion Simulations

Abstract:

One approach to model the high-frequency attenuation of spectral amplitudes of S-waves is to express the observed exponential decay in terms of Kappa factor. Kappa is a significant parameter used for identifying the high frequency attenuation behavior of ground motions as well as one of the key parameters for stochastic strong ground motion simulation method. Recently, it has been also used in adjusting ground motion predictions from one region to another. Currently, other than a previous study by the authors, there are no detailed studies on kappa using Turkish strong ground motion datasets. In this study, with the objective of deriving regional kappa models, we examine ground motion datasets from different regions in Turkey with varying source properties, site classes and epicentral distances. Statistical tools are used to investigate the dependency of kappa on these parameters. In addition, potential correlations between kappa and Vs30 values of the stations are also studied. Main findings of this study are regional kappa models on North Anatolian Fault zone. Finally, we also present high-frequency strong motion simulations of past events in the selected regions using the proposed kappa models. Regardless of the magnitude, source-to-site distance and local site conditions at the stations, the high-frequency spectral decay is simulated effectively.