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南北地震带南西缘的元谋-昔格达断裂新构造特征对认识区域构造地貌形变、强震分布与构造应力场之间的关系、以及其在块体运动中的活动方式和强震趋势意义重大.经开展该构造带地质、地貌、形变及活动性综合研究,表明:(1)元谋-昔格达断裂活动方式总体表现为第四纪早期的逆冲和晚期的左旋走滑兼局部挤压或张剪.(2)断裂切错的地层、地貌形变特点和探槽表明:江边以南,断层最新活动时间在距今6.92±0.70~8.68±0.94 ka之间;自20.82±2.12 ka以来,断层垂向活动速率约为0.096 mm/a,水平滑动速率为1~2 mm/a;断裂强活动复发间隔应不小于8.68±0.94 ka.江边以北,断裂最新活动时间晚于12.83±1.09 ka;晚更新世以来的左旋走滑速率约为1.70 mm/a,垂向速率为0.04~0.10 mm/a;断裂强活动复发间隔大致为1~1.2万年或更短.(3)前期成果表明断裂带自晚新生代以来主要受早期的NNE-SSW向和晚期的NNW-NWW向水平主压应力场作用,而晚期局部构造应力场表明,下雷弄-江边、化同-秧田井、一平浪-罗川一带倾滑明显,影响和调整了断裂带的晚第四纪活动特点.
The new tectonic features of the Yuanmou-Xigeda fault in the southwestern seismic belt in the southwestern seismic zone have great impact on the structural tectonic deformation of the recognized area, the relationship between the strong earthquake distribution and the tectonic stress field, and their movement patterns and strong earthquakes in block motion After the comprehensive study on geology, geomorphology, deformation and activity of the structural belt has been carried out, it is shown that: (1) The overall activity pattern of the Yuanmou-Xigeda fault is the early Quaternary thrusting and the late left-lateral strike-slip Or Zhang She. (2) The stratigraphic and geomorphologic deformations and trenches of fault-cutting faults indicate that the latest active time of faults in the south of the riverfront is between 6.92 ± 0.70 and 8.68 ± 0.94 ka since the end of the fault; since 20.82 ± 2.12 ka , The vertical fault movement rate is about 0.096 mm / a, the horizontal slip rate is 1 ~ 2 mm / a; the recurrence interval of strong fault activity should not be less than 8.68 ± 0.94 ka. The latest fault activity is later than 12.83 ± 1.09 ka. Since the late Pleistocene, the left-lateral slip rate was about 1.70 mm / a and the vertical rate was 0.04-0.10 mm / a. The recurrence interval of strong breaking activity was about 1 to 12,000 years or less. (3) The results show that since the late Cenozoic fault zone mainly by the early NNE-SSW and late NNW -NWW to the horizontal principal compressive stress field, and the late local tectonic stress field shows that the dip levees of Xialeingong-Jiangbian, Huitong-Yangtianjing, Pingpinglang-Luochuan area obviously affect and adjust the late fault zone Characteristics of the Four Seasons.