Simulation of strong ground motion from the 1995 Mw 6.5 Kozani-Grevena, Greece, earthquake using a hybrid deterministic-stochastic approach

Abstract

The 1995 Mw 6.5 Kozani-Grevena earthquake struck an area in northwestern Greece characterized by relatively low seismicity based on historical information and instrumental data. The ground shaking in the near-fault region was recorded by a strong-motion accelerograph in the city of Kozani, at a distance of about 23 km from the epicenter. In this article, broadband ground motions are generated at selected locations and at a dense grid of observation points extending over the causative fault of the 1995 Kozani-Grevena earthquake using a hybrid deterministic-stochastic method. Based on a multi-segment fault model with curved geometry proposed in the literature, the low-frequency components of the synthetic ground motion are simulated using the discrete wavenumber representation method and the generalized transmission and reflection coefficient technique. The high-frequency components of the synthetic ground motion are generated using the stochastic modeling approach and the specific barrier model. The two independently derived ground-motion components are then combined using matched filtering at a crossover frequency of 1.2 Hz to generate broadband ground-motion time histories and response spectra. The simulation results are validated by comparing the synthetic ground motions with the recorded ones in the city of Kozani and with estimates of peak ground-motion quantities inferred from ground-motion prediction equations.