摘要
为探究聊城—兰考断裂带中段的构造形态及其活动特征与构造应力场的关系,首先搜集整理研究区域内46个(2.0≤M_(L)≤4.4)地震震源机制解资料,并运用地震矩张量叠加求解总体震源机制的方法得到研究区断层状态表现为带有逆冲分量的走滑断层的结论;接着利用网格搜索法求出研究区最优的应力场参数:最大压应力轴σ_(1)走向角为13.57°、倾伏角为12.89°,中等压应力轴σ_(2)走向角为274.00°、倾伏角为36.00°,最小压应力轴σ_(3)走向角为120.00°、倾伏角为51.05°,应力比R为0.8;其次为考察断层的形态,利用小震位置拟合出研究区断层走向角为218.5°、倾角为84.43°,并结合前文得到的区域应力场参数估计该断层的滑动角为55.7°;最后结合研究区应力特征以及断层面上的应力分布分析出聊城—兰考断裂中段主要受到了NWW—SEE方向的拉伸以及该区域应力场近NNE—SSW向水平挤压的作用,在此应力场的作用下该断层以左旋走滑并带有一定的逆冲分量进行活动,这为后续研究者提供此地区更加精确的应力场信息。
In this study,the structural morphology of the central segment of the Liaocheng-Lankao fault and the relationship between its active characteristics and the tectonic stress field were explored.We first collected the focal mechanism data on 46 earthquakes(2.0≤M_(L)≤4.4)in the study area and performed seismic moment tensor overlay analysis to solve the overall focal mechanism.Results showed that the fault in the study area was a strike-slip fault with a thrust component.Then,we obtained the optimal stress field parameters in the study by using the grid search method and found that the strike angle and inclination angle of maximum compressive stress axisσ_(1)were 13.57°and 12.89°,respectively;the strike angle and inclination angle of medium compressive stress axisσ_(2)were 274°and 36°,respectively;the strike angle and inclination angle of minimum compressive stress axisσ_(3)were 120°and 51.05°,respectively;and the stress ratio R was 0.8.Second,the strike angle and dip angle of the fault were fitted by using the position of small earthquakes to investigate the fault morphology and were found to be 218.5°and 84.43°,respectively,and the rake of the fault was estimated to be 55.7°on the basis of regional stress field parameters.Finally,on the basis of the combination of the stress characteristics of the study area and the stress distribution on the fault plane,we concluded that the middle segment of the Liaocheng-Lankao fault was mainly subjected to the tension in the NWW-SEE direction and the horizontal compression of the stress field in the nearly NNE-SSW direction.Under the action of this stress field,the fault moved in a mode of left-lateral strike-slip with a certain thrust component.This study provides more accurate information on the stress field in the study region.Such information is convenient for future research.
作者
师涵博
万永革
张元生
SHI Hanbo;WAN Yongge;ZHANG Yuansheng(Institute of Disaster Prevention,Yanjiao 065201,Hebei,China;Hebei Key Laboratory of Earthquake Dynamics,Sanhe 065201,Hebei,China;Gansu Earthquake Agency,Lanzhou 730030,Gansu,China)
出处
《地震工程学报》
CSCD
北大核心
2022年第6期1478-1488,共11页
China Earthquake Engineering Journal
基金
河北省地震科技星火计划(DZ20200827053,DZ20200827056)
中央高校科研业务费专项(ZY20215117)
河北省地震动力学重点实验室开放基金项目资助(FZ212105)。
关键词
聊兰断裂中段
震源机制
网格搜索法
应力场
central segment of the Liaocheng-Lankao fault
focal mechanism
grid search method
stress field
