【摘要】 为研究霍山地区丛集地震活动地震断面的几何形状及滑动性质，本文基于安徽地震台网给出的2008年1月—2020年12月霍山区域内小震资料，采用双差精定位方法对研究区的地震进行精确定位，讨论了速度模型对定位结果的影响.然后，利用地震精定位结果计算了区域内三条地震断面(BB′,CC′,DD′)的几何参数(走向、倾角).其次，基于该地区丰富的小震P波初动资料，采用综合震源机制解法反演区域应力场，并结合断层的几何形状确定滑动性质.最后结合地质构造背景和应力场背景对发震断面进行分析，获得以下认知：(1)BB′断层走向为245.7°,倾角为85.6°,滑动角为167.3°;CC′断层走向为231.4°,倾角为88.5°,滑动角为173.2°;DD′断层走向为49.6°,倾角为87.5°,滑动角为-174.7°,三条地震断面与落儿岭—土地岭滑动性质一致，均为右旋走滑.(2)综合震源机制解结果显示，区域构造应力场呈明显低倾伏角EW向挤压和SN向拉张；区域应力场在三条断层上产生的相对剪应力及正应力均表明三条断层上的地震事件的发生为构造应力场作用下的正常应变释放，但受到了预先存在薄弱区的影响.(3)这三条地震断面为磨子潭—晓天断裂的雁列式右旋走滑分支断裂，商城—麻城断裂带和郯庐断裂带南端右行右阶错动拉分推测为其错动的动力学成因.更多还原

【Abstract】 In order to explore the properties of seismogenic structure and stress field in Huoshan area by clustered earthquake events, we collected seismic observational report of small earthquakes from January 2008 to December 2020 provided by Anhui Seismic Network. By using double-difference locating method, the locations of events in study area are precisely determined, and the influence of velocity model on earthquake locating result is discussed. Then, the fault geometry(strike, dip) of three seismogenic fault segments(BB′, CC′, DD′) is estimated by using the precisely relocated earthquake events. Secondly, by using the abundant small earthquake data in study region, the regional stress field is determined by the composite focal mechanism method, and the sliding property is estimated according to geometry of fault segments and the stress field. Finally, the seismogenic structure is analyzed in combination with background geological structure and stress field. The following understandings are arrived:(1) The strike, dip and rake of the BB′ fault is 245.7°, 85.6°and 167.3°, respectively. The strike, dip and rake of the CC′ fault is 231.4°, 88.5°, and 173.2°, respectively. The strike, dip and rake of the DD′ fault is 49.6°, 87.5°and-174.7°, respectively. The three seismic fault segments are all right-lateral strike-slip, which are consistent with the sliding property of the Luoerling-Tudiling fault.(2) The tectonic stress field in Huoshan area explored by composite focal mechanism solution is EW compression and SN extension with low plunge angle. The relative shear stress and normal stress on the three fault segments show that the seismic events on the fault segments is a normal strain release by the action of tectonic stress field, but affected by pre-existing weak zones.(3) The three seismic fault segments are the En echelon dextral strike-slip branch fault of the Mozitan-Xiaotian fault, whose slip properties are caused by pull-apart interaction of the right-lateral strike-slip of the Shangcheng-Macheng Fault and the south end of the Tanlu Fault.更多还原