Abstract：Directional delayed shot, a new method for generating S-wave with the use of dynamite, is adopted on the basis of research on combined P-wave and S-wave survey in mountainous region in Sichuan Province. This method needs a row of "direction-guidance"wells drilled near the seismic source point, a small charge being placed in each well. With the use of delayed blast technique, the small charges explode to creat cavities or "explosion funnel”before the exploding of the seismic source charge, so that the seisanic source charge explodes to cause directional shear stress wrich results in strong horizontal vibration. The shear wave record obtained in this method has high energy and high S/N ratio. The directionalities of the directienai delayed blast and horizontal detector are analysed. The analysis shows that the directional delayed blast generates SH wave (shear wave generated by horizontal vibration). Field observation method for combined P-wave and S-wave survey in mountainors region was develored on the basis of analysing shot mechanism, noise properties and the distributions of useful waves and noises in time-space domain.
