基于面波数据的地下核爆炸的全元素矩张量反演方法

Full moment tensor inversion method of underground nuclear explosions based on surface waves data

区域分层介质模型下,可以将地震波场描述为矩张量各分量作为权重的基本格林函数的线性组合,利用该理论地震波场可以反演实际天然地震或地下核爆炸的震源机制,反演结果中不同震源机制成分的比重,可以用来识别地下核爆炸,该系统方法越来越受到关注。给出了基于广义反射-透射系数方法的水平分层介质模型的地震波场正演公式,并对基于该公式的单台反演结果的准确性、稳定性、可靠性进行了理论分析,为利用该公式对实际地下核爆炸进行反演提供了理论基础,该方法对利用区域少量甚至是单站记录数据检测、识别地下核爆炸具有重要参考意义。

Powerful techniques have been developed for calculating the plane wave response of horizontally layered models. This method is quite general and is widely used in synthetic wave algorithms. Using this method, we can describe the displacements in terms of a linear combination of the moment tensor elements, and the moment tensor for an arbitrarily oriented dislocation can be given by this method. The moment tensor can be used to distinguish natural earthquakes and underground nuclear experiments according to its different elements. In this paper we rewrite the formula and estimate the reliability of the non-double-couple solutions on the basis of error analysis that includes the variance of modeling and of the noise in the data. Our analysis of synthetic data shows that this method is robust and can be used in the real data analyses. The result is significant for monitoring nuclear explosions by using data from just a few monitoring stations or even from a single station.