丽江—小金河断裂带现今断层运动特征  

Current fault movement characteristics in the Lijiang-Xiaojinhe fault zone

作　　者：刘晓霞[1] 邵志刚[1] LIU XiaoXia;SHAO ZhiGang(Institute of Earthquake Forecasting,China Earthquake Administration,Beijing 100036,China)

机构地区：[1]中国地震局地震预测研究所

出　　处：《地球物理学报》2020年第3期1117-1126,共10页Chinese Journal of Geophysics

基　　金：国家重点研发计划（2017YFC1500501）;震情跟踪定向工作任务（2019010211）;国家自然科学基金项目（41774090）联合资助

摘　　要：本文利用GPS观测对丽江—小金河断裂带的现今断层运动和变形状态进行了分析和探讨.丽江—小金河断裂带两侧地块地壳变形差异显著,GPS速度剖面结果显示断裂带两侧存在地壳变形不连续现象;进一步以GPS速度场为约束,基于负位错模型反演的丽江—小金河断裂带的断层闭锁空间分布结果显示,以木里为界,北东段断层强闭锁从地表向深部延伸至15 km左右,西南段断层闭锁程度较高的区域位于5~15 km范围内,浅层表现为弱闭锁的状态;滑动亏损速率结果显示,两闭锁段的滑动亏损速率相差近4 mm·a^-1,说明丽江—小金河断裂带西南段的背景滑动速率明显高于北东段.基于数值模拟分析了西南段浅层蠕滑运动对周边断层的影响,结果表明西南段的浅层左旋滑动对北东段闭锁区和西南段深部强闭锁区均为正影响.We studied on the current movements and deformation of Lijiang-Xiaojinhe fault using GPS observations.The results of GPS velocity profile show that the crustal deformation is discontinuous across the fault zone.And based on DEFNODE dislocation model,the distribution of locking factor of Lijiang-Xiaojinhe fault zone were calculated,and the results show that the northeastern segment is locked from ground surface to 15 km underground while the southwestern segment locked from 5 km to 15 km underground with area upon 5 km is weak locked.Combing with the results of GPS velocity profiles,we induced that it may behave as shallow creep in the southwestern segment of Lijiang-Xiaojinhe fault zone.Furthermore,the difference of slip deficit rate between two locking area is about 4 mm·a^-1,which indicate that the slip rate of the southwestern section of the Lijiang-Xiaojinhe fault zone is significantly higher than that of the northern section.Finally,we discussed the influence of the creep segment by calculating the Coulomb stress changes on other faults,which showed positive influence on the two locked areas.

关 键 词：丽江—小金河断裂带 GPS速度场 断层闭锁 库仑应力 

分 类 号：P223[天文地球—大地测量学与测量工程] P315[天文地球—测绘科学与技术]