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Title:: Analysis Based on the Meta-instability Theory of the Variation Characteristics of the Lithospheric Magnetic Field in Yunnan before the 2021 Yangbi,Yunnan M_S6.4 Earthquake

作者:: 陈政宇¹; 倪喆^1; 周思远¹; 王振东²; 王粲²; 赵育飞¹; (1.云南省地震局,云南昆明 650224; 2.中国地震局地球物理研究所,北京 100081)

Author(s):: CHENG Zhengyu¹; NI Zhe¹; ZHOU Siyuan¹; WANG Zhendong²; WANG Can²; ZHAO Yufei¹; (1.Yunnan Earthquake Agency,Kunming 650224,Yunnan,China)(2.Institute of Geophysics,China Earthquake Administration,Beijing 100081,China)

Keywords:: the Yangbi M_S6.4 earthquake; lithospheric magnetic field; horizontal vector; the meta-instability theory

摘要:: 回溯2021年云南漾濞M_S6.4地震前2017—2021年云南地区岩石圈磁场水平矢量逐年变化的空间分布特征,并与亚失稳理论中稳态-亚稳态-亚失稳态-失稳态的各阶段进程进行对比分析。结果表明:漾濞地震前,在震中及其附近区域出现的岩石圈磁场水平矢量弱变现象是震前的典型特征,其“弱变区域”的形成对应亚失稳O点,是野外观测当中最易识别的重要标识; 漾濞地震前连续4期弱变区域存在有“重叠”区域,同时其外围水平矢量量级增大且方向改变,则是进入到了“不可逆”的亚失稳OB阶段,预示着地震将要发生且震中在“重叠”区域的边缘,利用这种时空变化特征可以提前预判发震地点与时间。此外,该分析也是将亚失稳研究从室内实验走向野外观测的有益尝试。

Abstract:: The purpose of this paper is to explain the annual variation characteristics of the lithospheric magnetic field before the Yangbi M_S6.4 earthquake with the meta-instability theory.The spatial distribution characteristics year by year of the horizontal vector of lithospheric magnetic field in Yunnan province from 2017 to 2021 before the Yangbi M_S6.4 earthquake is reviewed and compared with the process of steady state-met-astable state-meta-instability state-instability state.The results show that the weakening region of the horizontal vector in the meta-instability O stage is the most easily recognized typical mark in field observation; There are “overlapping” zones in the weakening region for two consecutive periods or more,and the outer horizontal vector increase and change their direction.These mark the “irreversible” meta-instability OB stage,which indicates that the earthquake will occur at the edge of the “overlapping” region.It is a meaningful attempt to change the study of meta-instability theory from laboratory to field observation in addition.