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Title:: The Stress Field Inversion and Stress Field Partition of the Southern Tanlu Fault and Surrounding Areas

Author(s):: SONG Shangwu; WANG Qingliang; ZHANG Pei; LI Yuhang; ZHOU Lin; (The Second Monitoring and Application Center,China Earthquake Administration,Xi'an 710054,Shaanxi,China)

Keywords:: the focal mechanisms; the stress field; the divisional inversion; the southern Tanlu fault

摘要:: 基于震源机制解和地应力测量资料,研究分析郯庐断裂带南段及其周边地区的应力场分布特征,并结合大地构造特征将该区域应力场分为3个子区域:郯庐断裂带西侧应力区、苏北断陷应力区和苏南隆起应力区。分区反演构造应力场结果显示:(1)郯庐断裂带以西区域和苏北断陷区水平方向受到NEE向的挤压作用,苏南隆起区水平方向受到近EW向的挤压作用;(2)郯庐断裂带以西区域水平方向受到的挤压作用方向介于苏北断陷区NEE向与苏南隆起区近EW向之间;(3)郯庐断裂带以东区域构造应力场为正断兼走滑机制,以西区域为走滑机制;(4)整个研究区域水平方向挤压应力自西向东呈放射状分布。

Abstract:: Based on collection of focal mechanisms and in-situ stress measurements,we analyze the distribution feature of the stress field of the southern Tanlu fault and surrounding areas. Combined with the tectonic characters,we divided the study regions into three stress areas,i. e. the Tanlu fault west zone,the Subei rift zone and the Sunan uplift zone. Inverting the tectonic stress tensor of the three areas and analyzing the characters of each stress division,the results are as follows:(1)The west of Tanlu fault area and northern Jiangsu faulted area are extruded by the NEE stress in horizontal. The uplift area in the southern Jiangsu in horizontal is squeezing with the ～ EW stress.(2)The Tanlu west area is extruded in horizontal by the stress whose direction is between the NEE direction of the stress field in the northern Jiangsu and the ～ EW direction of the stress field in uplift area of southern Jiangsu.(3)The stress field in the east area of the Tanlu fault is controlled by the mechanism of normal fault with strike-slip component,and the stress field in the west area is controlled by the mechanism of normal strike-slip fault.(4)The direction of horizontal compressive stress in the entire study area distributes radially from west to east.