沙漠点爆炸震源产生的远场地震子波

Far-field seismic wavelet produced by point explo-sive source in desert.

理论分析表明 ,沙漠地震子波的主频随传播距离的平方成反比例下降 ,其系数与沙漠介质波速和震源特性有关 ,这种非线性变化将导致沙漠地震子波的显著低频化。文中给出了沙漠地震子波视主频的表达式 ,指出提高目标主频的根本办法 ,不在于无限制地加大炸药量和采用低爆速炸药 ,而在于加大震源激发井深 (增大 h0 )和扩大震源激发后冲击波的波阵面 (增大 γ0 )

Theoretic analysis showed that the dominant frequency of seismic wavelet in desert decreases in inverse proportion to square of spreading distance,its coefficients are related to the velocity of desert medium and the nature of source, this non-lin-earization leads to significant low-frequency of seismic wavelet in desert. The paper gave the for-mula of apparent dominant frequency of seismicwavelet in desert and pointed out that the funda-mental method for increasing the dominant fre-quency of targets does not lie on unlimitedly in-creasing charge size and using dynamite with low explosive speed and lie on increasing the explosivedepth of source(increasing h 0)and expanding wave front of shock wave after source explosion (in-creasing γ 0).