THE INFLUENCES OF RUPTURE PROPAGATION ON EARTHQUAKE GROUND MOTION

It is well known that the response spectra of the earthquake motions observed on the ground surface can be expressed by the equation R(w)-.F{۰(o),P(w))xG(w), where R is the response spectrum of the ground motion, ۰ is the source function, P is the attenuation function, and G is the amplification factor of the seismic waves which are observed at the site under consideration and the surrounding ground. The present study is mainly concerned with the expected peak acceleration values at a base rock level in the near field. These values are obtained for the destructive Kalamata (southern Greece) earthquake of Sep.۱۳, ۱۹۸۶, by considering the focal mechanism parameters and different modes of the rupture propagation. The computed values at the ground surface are in agreement with the recorded ones, especially those which correspond to a circular rupture propagation model.