长期以来的经验证明,在低速带内激发地震波是不行的,而在潜水面以下的胶泥层中最佳。潜水面下激发所产生的的面波最弱,而向下传播的能量最强。可是在大沙漠区中,一百几十米以上全是沙层,那有潜水面可寻,最多也只有些潮湿的砂层。浅表地层的基本特征是:0—10米为松散,干燥流砂,层速度为450—550米/秒; Long experience has shown that it is not feasible to excite seismic waves in the low-speed zone, but the best in the mastic layer below the diving surface. The surface wave generated by the submersible excitation is the weakest, while the energy propagated downward is the strongest. However, in the large desert area, more than 100 meters of sand are all over the area. There are diving surfaces to be found, at most, only a few wet sand layers. The basic characteristics of the superficial formation are: 0-10 m is loose, dry sand, layer velocity of 450-550 m / s;