Source and Path Parameters for Recorded Earthquakes in Tehran Province, Iran

抄録

 The goal of this study is to estimate source and path attenuation parameters of recorded earthquakes in Tehran province, Iran so they can be used for strong motion prediction purposes. For this, we have used four well recorded earthquakes recorded on Iran Strong Motion Network (ISMN). Assuming a simple geometric spreading of 1/r we have estimated Q factor for S-wave attenuation by characterizing spectral amplitude decay with distance at discrete frequencies. We propose the form of Q(f)=73f^0.72 for attenuation of S-wave in Tehran province. We show that the proposed attenuation quality factor is in the range of Q factors that have been proposed by the other studies. We have also estimated source parameters, such as seismic moment (M₀), corner frequency (f_c) and Brune stress drop (Δσ) for each earthquake. We have fitted Brune source model to the observed spectra of motion by a grid search for least squares. Stress drop for studied earthquakes ranges between 7.7 to 37.1 MPa (77 to 371 bars).