利用 Lg 波谱特征估计地下核爆炸装置的埋深

摘要

The efficient frequency-wave number code could synthesize high-frequency (10 Hz) regional seismograms (up to a distance of more than 1 000 km)in a medium consisting of a large number of crustal layers,and investigate the effects of regional wave guides on Lg-waves.Lg-waves contain source information and the effect of the near-source structure.The scattering of explosion-generated Rg into S appears to be the primary contributor to the low-frequency Lg from nuclear explosive devices.For three typical crustal models,the synthetic seismograms calculated for EXP and Spall sources show that the generation mechanism of Lg-waves can be explained by a compensated linear-vector dipole source.If the velocity structure is well known,then the Lg-wave-form can be synthesized,so we can compare the theoretical Lg-wave’s spectrum with the observa-tion’s spectrum,and the results can not only be used to estimate the depth of the underground explosion equipment but also a discriminant.A deep understanding of the mechanism of the generation of Lg-waves can help us to create a new discriminant.%Lg 波同时携带地球介质结构信息和爆炸源引起的二次源信息，是研究地下爆炸震源机制及检测、识别手段的重要震相。基于对某一区域介质结构的了解，将实测 Lg 波谱特征形态与理论波谱形态进行比对，利用 Lg 波频谱曲线的低谷点随震源深度“左移”的特征，作为辅助识别手段估计地下核爆炸装置的埋深。研究结果对深入地理解地下核爆炸震源机制有重要的参考意义。