Abstract: By using of wave data from the Lanzhou digital seismic network, quality factor Q values of S wave inelastic attenuation had been studied in Gansu region. It has been obtained that the frequency-dependent inelastic attenuation Q value is Q(f)=374.0^0.3084 in the southeastern Gansu, and Q(f)=693.6f^0.2865 in the middle-east segment of the Qilianshan. The results show that there exists great difference in the subarea Q values, presenting the heterogeneity of Q value space distribution. The Q value is lower in southeastern Gansu area, and higher in the middle-east segment of the Qilianshan. These spatial differences of Q value distribution is in accordance with the regional difference of tectonic activity, seismicity and geothermal structures in Gansu region. The zones with intensively tectonic activities and higher geothermal activities belong to low Q value zones, where seismic waves attenuate more rapidly.

Key words: Gansu region, Simultaneous inversion, Inelastic attenuation, Q value, SH-wave