2017年9月3日朝鲜地下核试验的地震学鉴别和当量估计  

Seismological discrimination and yield estimation of the 3 September 2017 Democratic People's Republic of Korea(DPRK) underground nuclear test

作　　者：赵连锋[1,2] 谢小碧 何熹 赵旭 姚振兴[1,2] 

机构地区：[1]中国科学院地质与地球物理研究所,中国科学院地球与行星物理重点实验室,北京100029 [2]中国科学院地球科学研究院,北京100029 [3]Institute of Geophysics and Planetary Physics,University of California,Santa Cruz,CA 95064,USA

出　　处：《科学通报》2017年第35期4163-4168,共6页Chinese Science Bulletin

基　　金：国家重点研发计划(2017YFC0601206);国家自然科学基金(41674060,41374065,41630210)资助

摘　　要：北京时间2017年9月3日11时30分在朝鲜境内发生一次强烈地震事件.利用区域地震数据中纵波和横波的振幅谱比值,我们确认这是一次爆炸事件.8 min后在同一位置发生一次余震,确定是事后由爆炸产生的腔体坍塌引起的陷落地震事件.利用区域震相Lg波和Rayleigh波获得此次核试验的体波和面波震级分别是m_b(Lg)=5.6±0.2和M_s=5.1±0.2.采用体波震级与当量的经验关系式,假定爆炸与周围岩体完全耦合而且置于正常埋藏深度,此次朝鲜核试验的地震学当量约为56 kt.考虑到震级误差,当量估计的不确定性范围是30~100 kt.如果实际埋藏深度达到1000~2400 m,则爆炸当量可能达到100~200 kt.At 11：30 on September 3, 2017 （Beijing time）, a strong earthquake occurred in Democratic People＇s Republic of Korea （DPRK）. International seismic monitoring agencies, e.g., the China Earthquake Network Center （CENC） and the United States Geological Survey, suspected that it is an explosion. Based on seismic data from the China National Digital Seismic Network （CNDSN） and Global Seismic Network （GSN）, we investigated characteristics of this event and an aftershock 8 min after the main event. The P- and S-wave excitation functions of explosion and earthquake sources are scaled differently. Therefore, the P/S-type spectral ratios can be an effective discriminant for separating explosions from earthquakes, Using the P/S spectral ratios Pg/Lg, Pn/Lg and Pn/Sn as discriminants, we confirmed the 3 September 2017 event was an explosion. For the aftershock occurred after the main event, we identified it is a collapse, likely caused by the failure of the explosion generated cavity. Using a pre-calibrated regional seismic network in Northeast China and the Korean peninsula, and the regional Lg-wave at- tenuation model developed previously, we obtained the Lg wave body wave magnitudes for the 3 September 2017 main event and its aftershock to be mb（Lg）=5.6_0.2, and 3.95_＋0.04. We used a group of historical events to calibrate the regional network for calculating Rayleigh wave magnitude. After correcting for the site responses, the network averaged surface wave magnitudes for the main shock and the aftershock were obtained to be M~=5.1＋_0.2 and 3.95＋_0.08. To test body-wave versus surface-wave magnitude as a potential discriminant, we compared the M~ （Rayleigh） and rnb （Lg） for all 6 DPRK nuclear explosions and a group of earthquakes in Northeast China and the Korean peninsula. The explosion and earthquake populations were largely overlapped with each other. The above results show that the P/S ratio method is a more effective discriminant than the mb（Lg）-M~ criterion in Northeast

关 键 词：朝鲜 地下核试验 区域地震波 鉴别 当量估计 

分 类 号：E93910.6[军事—军事装备学]