Abstract: The deep-shallow geological structural conditions and seismic activities for the Shenyang M5 1/2 earthquake in 1765 are analyzed, the activities and seismic hazards for the Changbaixiang-Guanyinge fault (F6), the Yilan-Yitong fault, the Hunhe fault which around the epicenter are also evaluated. It is analogised of seismic structure for mid-strong earthquakes in the area of Liaoning. It is determined that the modern tectonic deformation features for the F6 is coincident with the effect of modern tectonic stress. Results of shallow seismic prospectings, progressive features of fault ruptures, aging data and offset landform show that the F6 is still active in late Quaternary. Modern slight shocks distribute along the F6. The F6 interjuncts to the Hunhe fault at the depth of 5-6 km or more, it has an echelon structure in planimetric trend, and the length of fault segment is about 20-25 km. The F6 possess the condition of gestating and generating an earthquake of 5 1/ 2 or so. The F6 is determined to be more active than the Yilan-Yitong and the Hunhe fault, and it has a higher seismic hazard. The F6 is the seismogenic structure for the Shenyang M5 1/2 earthquake in 1765.

Key words: Shenyang, earthquake, Changbaixiang-Guanyinge fault, seismogenic structure, determination

摘要： 对1765年沈阳51/2 级地震的深、浅部地质构造条件、地震活动特征进行了分析, 对震中附近的长白乡-观音阁断裂( F6) 及依兰-伊通断裂、浑河断裂的活动性和地震危险性进行了评价, 并与辽宁地区的中强地震活动进行了构造类比。认为 F6 的现代构造变形特征与构造应力条件一致, 浅层地震探测、断裂破碎带发育特征和测年数据、断错地貌特征等均显示 F6 在第四纪晚期仍有活动, 现代微小地震活动沿 F6 呈条带状分布。F6 在 5～6 km 或更大的深度上与浑河断裂等具有复合交叉结构, 在平面展布上具有斜列状结构, 断裂段的长度约 20 ～25 km 左右,具备孕育和发生51/ 2 级左右地震的条件。判定 F6 断裂是比依兰-伊通断裂和浑河断裂等区域性断裂具有更强的活动性和地震危险性的断裂构造, 是 1765 年沈阳51/ 2级地震的发震构造。

关键词: 沈阳, 地震, 长白乡-观音阁断裂, 发震构造, 判定