Constraining the sub-surface S-wave velocity of the northeastern margin of Tibetan Plateau with receiver functions

We systematically investigated the effect of sub-surface S-wave velocity on the direct wave (Pp) of receiver function by the formula derivation and numerical tests. The results indicated that the sub-surface S-wave velocity can be determined with the receiver function amplitude. This method has been applied to the teleseismic waveforms of 36 stations in the northeastern margin of Tibetan Plateau, and obtained the sub-surface S-wave velocity distribution within the depth range of 5 +/- 2.5 km. The results show that the sub-surface S-wave velocity is smaller in the Qilianshan-Hexi corridor region, and is more complicated in the southeastern Gansu region of terrain gradient zone. The comparison of the sedimentary thickness and the sub-surface S-wave velocity implies that the sub-surface S-wave velocity is negatively correlated with the sedimentary thickness. This method is an effective supplement to the application of receiver function. Comparing with the traditional active-source seismic exploration, the cost of our method is nearly ignorable, as well environmentally friendly. So this method also has great potential with the exponential increasing of seismological observations in the future.