Estimation of the frequency-dependent shear wave Quality Factor from acceleration spectra of the Kahak-Qom earthquake 2007

Estimation of the frequency-dependent shear wave Quality Factor from acceleration spectra of the Kahak-Qom earthquake 2007

In this study high-frequency strong-motion data of Kahak earthquake have been analyzed to determine the Qβ(f) and source parameters by inversion of the recorded data. The data represented 21 accelerograms recorded from Kahak-Qom earthquake in the hypocentral distance range from 16 to 160 km. The seismic hazard map for this region illustrates that most of the area in this province is located within high relative risk and characterized by a large number of heterogeneities. For frequency band of 1 to 20 HZ, the frequency-dependent attenuation for this region found to be Qβ = 167f 0.78. Moreover, the source term obtained from inversion was analyzed to estimate various source parameters. Thereby, we estimated seismic moment (3.98×1024dyne-cm), corner frequency (0.17 Hz ), source radius (7.2 Km), stress drop (10.23 bars), which are found to be consistent with the corresponding values reported in published studies. The authenticity of achieved Qβ (f) relation is checked by comparing the source spectra in various stations with the theoretical spectra. Low values of the coefficient (Q 200) in the Qβ (f) relation suggest that the region is seismically and tectonically active.

In this study high-frequency strong-motion data of Kahak earthquake have been analyzed to determine the Qβ(f) and source parameters by inversion of the recorded data. The data represented 21 accelerograms recorded from Kahak-Qom earthquake in the hypocentral distance range from 16 to 160 km. The seismic hazard map for this region illustrates that most of the area in this province is located within high relative risk and characterized by a large number of heterogeneities. For frequency band of 1 to 20 HZ, the frequency-dependent attenuation for this region found to be Qβ = 167f 0.78. Moreover, the source term obtained from inversion was analyzed to estimate various source parameters. Thereby, we estimated seismic moment (3.98×1024dyne-cm), corner frequency (0.17 Hz ), source radius (7.2 Km), stress drop (10.23 bars), which are found to be consistent with the corresponding values reported in published studies. The authenticity of achieved Qβ (f) relation is checked by comparing the source spectra in various stations with the theoretical spectra. Low values of the coefficient (Q 200) in the Qβ (f) relation suggest that the region is seismically and tectonically active.