使用双差定位方法，对2013年4月20日08时02分芦山M7.0地震后近10天的余震进行重新定位，获得精度较高的重定位结果；在此基础上，对余震空间分布特征进行了研究，可知：①余震总体展布长度约35km, 宽度约20km, 优势深度范围为8—22km, 浅部地震少。M_L≥4.0地震震源深度均位于地表下16—22km,发震部位较深，可能是此次地震未造成明显地表破裂的原因之一；②至少92﹪的M_L≥4.0余震发生在前期。前期余震展布倾角较小，后期余震震级相对较小，且展布倾角较大；③发震断层走向约223°，倾向NW,倾角约39°，推测芦山主震的发震断层可能为大川—双石主断裂东侧的一条次级隐伏逆冲断层。

This study used the double difference location method,to relocated the nearly 10 days aftershocks after Lushan M7.0 earthquake On April 20, 2013 at 08 o´clock 2 minutes, the relocation results with higher accuracy are obtained；And on this basis,studied the space distribution features of aftershocks,draw the following conclusion:（1）The Aftershocks overall distribution length is about 35km, width is about20km, the main depth is between 8-22km.All M_L≥4.0 earthquake focal depth is between 16-22kmunder the surface,focal depth is deeper,this may be one reason why the earthquake not caused obvious faulting；（2）At least 92﹪ M_L≥4.0 aftershocks occurred in early，the early aftershocks distribution Angle is smaller；the later aftershocks magnitude is not only smaller,and that distribution Angle is bigger；（3）The Fitted seismogenic fault strike that according to the spatial distribution of the aftershocks and the main source location is 223 degree, The tendency is roughly north-west，dip angle is about 39 degree,the inferred seismogenic fault may be a secondary concealed thrust fault on the east side of the Dachuan-Shuangshi main fault.