Estimation of the quality factor in shallow soil using surface waves

Based on Rayleigh wave recorded in a 55 m long profile, dispersions of phase and group velocities in 5–40 Hz are obtained by multi-channel recording and processing method. Further, the velocity structures of shear waves in the soil above 35 m are obtained by inversions of velocity dispersions. Meanwhile, the spatial distribution of amplitude spectra of fundamental mode of Rayleigh waves is calculated, the dispersion curves of attenuation coefficients by using linear regression method are also given, and finally, the structures of Q _β in each soil layer are obtained by inversion. The results show that Q _β<10 in soft deposit layer and Q _β is about 30 in weathering bedrock. This project is supported by the National Science Foundation of Yunnan Province.