郯庐断裂带安徽段及“霍山窗”断层活动特征与地震关联性研究

Fault Activity and Correlation Study of Tan-Lu Fault Zone and “Huoshan Seismic Window”

利用郯庐断裂带安徽段及“霍山窗”区域的跨断层水准测量资料,运用断层形变累积率及年滑动速率比方法计算各测线近20a的观测数据,研究区域内断层活动及能量积累的整体空间演化特征,梳理各测点所跨断裂带的断层形变特征及变化过程,从空间分布和时间演化的角度探讨断层活动特征与安徽及邻近地区中强地震的关联性。结果显示:1)郯庐断裂带安徽段断层形变累积率总体高于“霍山窗”区域,震前存在高值聚集、区域分界、高密度低值梯度带等特征,显示震前的应力积累背景;2)安徽地区断层活动明显受郯庐断裂带整体活动的影响,区域性差异和阶段性变化显著;3)断层形变的年滑动速率比异常对地震活动的判断具有一定的指示作用,主要表现为震前2个月~1a的高值异常及多个测点的群体性异常等特征,随着震级的增大,异常分布范围和变化幅度均有所增大。

We use the cross-fault deformation measurement data of Tan-Lu fault zone in Anhui section and“Huoshan seismic window”,and calculate each line observation data for nearly 20 years utilizing the method of fault deformation accumulation rate and annual sliding velocity ratio.We analyze the fault activity,energy accumulation,and evolution characteristics of whole space in the study area,comb the various points across the fault deformation characteristics of the fault zone and the change process,and discuss the relation between fault activity and moderate earthquakes in Anhui province and adjacent areas from the angle of space distribution to the time evolution characteristics.Our results show that:1)The cumulative rate of fault deformation in the Anhui section of the Tan-Lu fault zone is higher than that of the“Huoshan seismic window”.Before the earthquake,there are high-value clusters,regional boundaries,high-density low-value gradient zones,etc.,showing the background of stress accumulation before the earthquake.2)The fault activity in Anhui area is obviously affected by the overall activity of the Tanlu fault zone,and the regional and periodic changes are significant.(3)The annual slip rate of fault deformation has a certain indication effect on the judgment of earthquake activity,mainly as before the earthquake.The characteristics of high-value anomalies of 2 months to 1 year,and group anomalies of multiple points,increase with increased magnitude.