ABSORPTION OF THE Pg, Sg WAVE IN AROUND KEMALİYE AND NEW MAGNİTÜDE FORMULA

The attenuation properties of seismic waves are one of the basic physical parameters used in seismological studies and earthquake engineering, which is closely, related the seismicity and regional tectonic activity of a particular area. In this study, we aimed to obtain attenuation coefficient of crust of Kemaliye city and its surrounding. In total 165 near-fields earthquake data recorded by the Kemaliye Station of Ataturk University Earthquake Research Center (AUERC) were used for the calculations. Maximum amplitudes of Pn and Sg waves were used in order to compute the earthquake magnitude. The attenuation has been determined by using the Chobra-Alexeev model based on the epicentre distance-amplitude relations. The linear equations systems obtained for the all events were solved using the least-squares method. Amplitude normalization process was performed for a reference value ML= 3,2, so as to correct effect of the magnitudes. The attenuation on calculation of attenuation coefficients (Pγ) 0.0207 1/km and (Sγ) 0,0358 1/km were obtained with the assistance of normalized amplitudes values for the region.