6:15 PM - 7:30 PM
[SSS26-P06] Effect of seismic attenuation on S-wave polarization anisotropy
Keywords:seismic attenuation, S-wave polarization anisotropy
Three-component response functions caused by P-wave incident on the bottom layer is calculated as a function of back azimuth for the three layer structure by layer matrix method (Crampin, 1970). Incident angle is set at 10 degrees measured from the vertically downward direction. The radial and transverse components of P-wave receiver functions for different back azimuths are constructed from the P-wave response functions by water level method (Langston, 1979).
We compared P-wave receiver functions calculated in two cases: one is a case where seismic attenuation exists and the other is a case where there is no seismic attenuation. The receiver function with seismic attenuation shows smoother waveform than that in the case of no attenuation, because high-frequency components of the receiver functions are attenuated by anelasticity of the anisotropic layers. We identified two conspicuous phases on the receiver functions as Ps-converted phases generated at layer boundaries. By using stripping method (Oda, 2011), we estimated splitting parameters, fast polarization direction and split time, of the Ps phases. Values of the estimated splitting parameters, with or without seismic attenuation, are approximately in agreement with those predicted from the anisotropic parameters of the three-layer velocity model. Thus we can say that the seismic attenuation does not have a significant influence on the shear-wave polarization anisotropy of Ps phases.