坚固体孕震模式的地磁日变化感应电流异常证据与完善——以2016年杂多6.2级、2017年九寨沟7.0级和2017年米林6.9级地震为例  

EVIDENCE AND REFINEMENT OF GEOMAGNETIC DIURNAL INDUCED CURRENT ANOMALY BASED ON HARD BODY SEIS-MOGENIC MODEL:TAKING THE 2016 ZADOI M6.2 EARTH-QUAKE,THE 2017 JIUZHAIGOU M7.0 EARTHQUAKE,AND THE 2017 MILIN M6.9 EARTHQUAKE AS EXAMPLES

作　　者：戴勇[1] 吴迎燕[2] 冯志生[3] 姚丽[4] 姜楚峰 孙君嵩 章鑫 冯丽丽[7] 李军辉[8] DAI Yong;WU Ying-yan;FENG Zhi-sheng;YAO Li;JIANG Chu-feng;SUN Jun-song;ZHANG Xin;FENG Li-li;LI Jun-hui(Earthquake Agency of Inner Mongolia Autonomous Region,Hohhot 010010,China;Institute of Earthquake Forecasting,China Earthquake Administration,Beijing 100003,China;Jiangsu Earthquake Agency,Nanjing 210014,China;China Earthquake Networks Center,Beijing 100045,China;Hubei Earthquake Agency,Wuhan 430071,China;Guangdong Earthquake Agency,Guangzhou 510070,China;Qinghai Earthquake Agency,Xining 810001,China;Anhui Earthquake Agency,Hefei 230031,China)

机构地区：[1]内蒙古自治区地震局,呼和浩特010010 [2]中国地震局地震预测研究所,北京100003 [3]江苏省地震局,南京210014 [4]中国地震台网中心,北京100045 [5]湖北省地震局,武汉430071 [6]广东省地震局,广州510070 [7]青海省地震局,西宁810001 [8]安徽省地震局,合肥230031

出　　处：《地震地质》2022年第6期1574-1596,共23页Seismology and Geology

基　　金：中国地震局地震科技星火计划项目(XH200501);中国地震局地震预测研究所基本科研业务专项(2021IEF0709);中国地震局监测预报司震情跟踪项目共同资助;国家重点研发计划项目(2017YFC1500502)。

摘　　要：文中研究了2016年杂多6.2级、2017年九寨沟7.0级和2017年米林6.9级地震前1~3a内地磁日变化感应电流的线状集中分布和短期原地重现异常的空间分布特征,发现线状感应电流的重叠段有围空现象,并依据重叠段异常产生的机理丰富和完善了坚固体孕震模式,获得的主要结论包括:(1)重叠段空区是坚固体在中—下地壳和上地幔分布范围的反映,这与地震空区是坚固体在中—上地壳分布范围的反映相类似,重叠段空区是发生在震前1~3a、坚固体孕震模式第3阶段的异常;(2)重叠段异常是中—下地壳和上地幔高阻体之间出现带有上拱性质的相互拆离滑动事件导致的高阻体之间高导层出现的短时间高导电流通道,其中上述拆离滑动事件是由深部热流体上涌引起的,它是坚固体孕震模式中发生在中—下地壳和上地幔的能量向坚固体运移的事件;(3)临震阶段震源体孕震断层内的各个密封高压流体不会同时破裂,早期破裂的密封高压流体与深部上涌进入断层内的高压热流体及断层内原有的自由水可能使得断层内遍布自由水,并在震源体孕震断层内形成有临震意义的高导电流通道,发现临震阶段震源体孕震断层内的高导电流通道对地震短临预报具有现实意义;(4)重叠段异常探测发现的中—下地壳和上地幔拆离滑动事件可能是大陆下方有热流体上涌运移参与的慢地震,但这一推测还需要基于测震学原理的研究结果加以论证。This paper studies the linear concentrated distribution of geomagnetic diurnal induced current and the spatial distribution characteristics of short-term in-situ recurrence anomalies in the 1~3 years before the 2016 Zadoi M6.2 earthquake,the 2017 Jiuzhaigou M7.0 earthquake and the 2017 Milin M6.9 earthquake.The main conclusions are as follows:(1)The overlapping segment anomalies occurring within 1~3 years before strong earthquakes usually have the phenomenon of seismic gaps.The overlapping segment gap is a large high-resistance body and also a hard body(hard inclusion)in the seismogenic model of hard body.Overlapping segment gap and seismic gap are the detection results of hard body with different depth distribution range by different physical detection methods.The distribution range of hard body is delineated by seismic gap in the upper and middle crust and overlapping segment gap in the middle-lower crust and upper mantle.The overlapping segment gaps occurred within 1~3 years before strong earthquakes,which are the anomalies in the third stage of the seismogenic model.The seismic gap before strong earthquakes has different stages.For example,background gaps are formed decades of years before strong earthquakes,and the gaps formed again about 1 year before the earthquakes.(2)The overlapping segment anomalies occurring within 1~3 years before strong earthquakes reflect the formation of short-time high conductive current channels in the high conductive layers among high resistance bodies.These short-time high conductive current channels are caused by the mutually detached slip events with up-arching property among the high-resistivity bodies located in the middle-lower crust and upper mantle,resulting from the upwelling of deep thermal fluid.They are the events in which the energy in the middle-lower crust and upper mantle migrates to the hard body in the seismogenic model of hard body,while the seismic gap events are the ones in which the energy in the middle-upper crust migrates to the hard body before the earth

关 键 词：地磁日变化 感应电流 热流体 上涌 拆离滑动 孕震模式 坚固体 慢地震 

分 类 号：P315.721[天文地球—地震学]