基于共现分析的川滇菱形块体MS≥5.0地震时空结构特征及趋势判断  

Spatiotemporal characteristics and tend assessment of MS≥5.0 earthquakes in the Sichuan-Yunnan rhomboid block based on co-occurrence analysis

作　　者：万佳 延军平[1,2] 王晓萌[1,2] 汪成博 武亚群[1,2] WAN Jia;YAN Jun-ping;WANG Xiao-meng;WANG Cheng-bo;WU Ya-qun(School of Geography and Tourism,Shaanxi Normal University,Xi'an 710119,China;National Demonstration Centre for Experimental Geography Education,Shaanxi Normal University,Xi'an 710119,China;North Minzu University,Yinchuan 750021,China)

机构地区：[1]陕西师范大学地理科学与旅游学院,西安710119 [2]地理学国家级实验教学示范中心(陕西师范大学),西安710119 [3]北方民族大学,银川750021

出　　处：《地球物理学进展》2020年第3期882-892,共11页Progress in Geophysics

基　　金：国家自然科学基金项目“中国西部地震灾害时空对称性结构精细化对接研究”(41877519)资助.

摘　　要：基于川滇菱形块体近300年完整的地震资料,运用Salton指数、可公度理论、蝴蝶结构图和可公度结构系对川滇菱形块体地震共现率、时空对称特征及其发生趋势进行分析,结果显示:(1)小江断裂、块体内NE向断裂和块体内NW向断裂为川滇菱形块体断裂带关联度模型的中心节点,且小江断裂与块体内NW向断裂关联度最强.(2)2021年小江断裂-块体内NW向断裂发生MS≥5.0地震信号强烈.(3)震中迁移具有良好的空间四边形对称结构,块体内NW向断裂震中呈现南北对称回旋迁移的特点;小江断裂震中迁移纬向以26.20°N,经向以102.81°E为对称轴,呈现"三同一异"的规律迁移,综合判断未来震中向位于川滇菱形块体东界的小江断裂北段迁移.(4)在地球自转"十年起伏"加速阶段,小江断裂-块体内NW向断裂地震发生概率较高;在月尺度分布上,地球自转速率季节变化当月小江断裂发震概率为54.54%,滞后一月块体内NW向断裂发震概率为60%.Based on complete seismic data from the last 300 years,the Salton index,commensurability information,a butterfly diagram,and a commensurability structure system were used to analyze the spatiotemporal symmetry and assess the trends of MS≥5.0 earthquakes in the Sichuan-Yunnan rhomboid block.The results show that the Xiaojiang,NE,and NW fault zones are the central nodes in the correlation degree model of the Sichuan-Yunnan rhomboid block,and the correlation degree between the Xiaojiang and NE fault zones is the highest.The next earthquake may occur in 2021,as the seismic signal is strong.The epicenter migration has a good spatial quadrilateral symmetrical structure,as the epicenters show the characteristics of north-south cyclotron migration in the NE fault zone.The epicenter migration symmetry axis in latitude is 26.2°N and the longitude is 102.81°E in the Xiaojiang fault zone.The next epicenter may migrate toward the northwest part of the Xiaojiang fault zone,which is located east of the Sichuan-Yunnan rhomboid block.A good correlation exists between the Earth's rotational velocity and earthquake occurrence time.The earthquake occurrence probability is high at the acceleration phase of the Earth's rotational velocity interdecadal variation.In the monthly scale distribution,the earthquake occurrence probability is 54.54%in the Xiaojiang fault zone in the month of the Earth's rotational change and 60%in the NE fault zone after one month of the Earth's rotational change.

关 键 词：川滇菱形块体 共现率 可公度 地球自转 地震 

分 类 号：P315[天文地球—地震学]