利用区域地震资料监测朝鲜地下核试验的研究进展  

Research progress on monitoring the North Korean underground nuclear tests using regional seismic data

作　　者：赵连锋[1] 谢小碧[2] 何熹 张蕾 杨庚 姚振兴[1] Zhao Lianfeng;Xie Xiao-Bi;He Xi;Zhang Lei;Yang Geng;Yao Zhenxing(Key Laboratory of Earth and Planetary Physics,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Institute of Geophysics and Planetary Physics,University of California at Santa Cruz,Santa Cruz,CA 95064,USA)

机构地区：[1]中国科学院地质与地球物理研究所地球与行星物理重点实验室,北京100029 [2]美国加州大学圣克鲁兹分校地球物理与行星物理研究所,圣克鲁兹CA 95064

出　　处：《地球与行星物理论评（中英文）》2025年第2期148-156,共9页Reviews of Geophysics and Planetary Physics

基　　金：国家自然科学基金资助项目(U2139206)。

摘　　要：根据朝鲜6次地下核试验在中国东北及邻近地区产生的宽频带区域地震资料,中国科学院地质与地球物理研究所地震学学科组发展了一套用于监测地下核试验的地震学方法,主要包括震级测量和当量估计、高精度震中定位以及爆炸与天然地震事件识别等.在全球范围内,存在多个用于震级-当量转换的经验公式,确定何种公式适合于朝鲜半岛地区至关重要.通过搜集一组用于地震测深的化学爆炸的当量和埋深,并以这些已知爆炸源作为量规事件,能够标定朝鲜地下核试验场的震级-当量关系,从而实现对朝鲜地下核爆进行当量估计.在精确定位方面,发展了利用多事件之间波形互相关方法精确测定它们之间的走时差从而完成高精度相对震中定位.通过进一步利用Pn和Pg等多震相数据还实现了对核爆深度的相对定位.在爆炸震源识别方面,利用统计处理方法分析研究了不同类型事件所产生地震波的特征,包括6次地下核试验、4次天然地震和3次化学爆炸,以及一些矿区塌陷等.结果发现P和S类型波的振幅比,例如Pn/Lg、Pg/Lg和Pn/Sn等,在2 Hz以上能够较好区分各类震源.其中爆炸震源产生的振幅比显著高于天然地震的值.特别是,通过计算谱振幅比的台网平均值能够显著提高识别的可靠性.利用中国东北和附近地区地震台网所提供的数据可以准确地将朝鲜地下核试验从周边天然地震事件中识别出来.该方法同时得到化学爆炸的P/S谱振幅比值介于核爆炸和天然地震的群组之间.Based on broadband regional seismic data generated by six North Korean underground nuclear tests,recorded by networks in Northeast China and adjacent areas,this paper developed a set of seismological methods to monitor North Korean underground nuclear tests,including magnitude measurement and yield estimation,high-precision relocation,and discrimination between atomic explosions and natural earthquakes.Since the North Korean nuclear test site(NKTS)is uncalibrated,it is crucial to determine the appropriate empirical magnitude-yield equation for the NKTS.This paper gathered ground truth data from chemical explosions used for deep seismic sounding,including their locations,yields,and charge depths,and determined a magnitude-yield relation suitable for the NKTS.A high-precision relative relocation method was applied to the six nuclear explosions at NKTS.To further alleviate the tradeoff between the detonate time and the source depth,according to the fact that the Pn and Pg waves have different incident angles,Pn and Pg waveform correlations are jointly used to increase the accuracy of relative source depth calculation.By analyzing the P/S type spectral amplitude ratios,Pn/Lg,Pg/Lg,and Pn/Sn,for 6 nuclear tests,4 natural earthquakes,and 3 chemical explosions,this paper found that,at above 2 Hz,the network averaged spectral amplitude ratios could reliably separate the North Korean nuclear tests from the natural earthquakes.The spectral amplitude ratios of 3 chemical explosions are located between those of the nuclear explosions and the natural earthquakes.

关 键 词：爆炸当量估计 震源相对定位 爆炸和天然地震识别 朝鲜地下核试验 

分 类 号：P315[天文地球—地震学]