利用全元素矩张量反演方法识别地下核爆炸

Distinguishing underground nuclear test by full moment tensor inversion

将震源矩张量中的各分量作为权重因子,利用基本Green函数的线性组合可以对地震波场进行描述,本文利用水平分层模型下的广义反射-透射系数方法的地震波场正演公式,反演了苏联东哈萨克斯坦地下核试验场的7次地下核爆炸、3次震中位置相近的天然地震的震源矩张量,反演结果表明地下核爆炸震源明显含有爆炸源成分,同时包含双力偶成分(DC)和线性偶极补偿源成分(CLVD),且CLVD成分比重大,CLVD的存在可用层裂机制来解释;天然地震震源矩张量的反演结果表明,DC源为主要成分,符合剪切位错震源模式。

The full moment tensor inversion is an important tool to monitor underground nuclear tests,thus has been employed in this paper to analyze the recorded data of seven underground nuclear tests and three natural earthquakes in the region of Eastern Kazakhstan.The results show that,except the obvious explosion source in underground nuclear tests,the components of double couple(DC)and compensate linear vector dipole(CLVD)also exist,in which the later plays a more important role and could be explained by the explosion-induced spall.In the case of natural earthquakes,the DC component is the main contribution,in consistent with the model of shear dislocation seismic source.