Based on the field survey results, the geological and geomorphic evidences of Late Quaternary activity and paleoseismic events in Tongdian-Madeng basin section of Weixi-Qiaohou fault are studied. The results show that the segment is active during Holocene and dominated by dextral strike slip. Its horizontal slip rate is 1.8-2.4 mm/a, and vertical slip rate is 0.30-0.35 mm/a since the Holocene. The OSL ages of faulted strata revealed by Yushuiping trench are 5.1±0.6, 5.3±0.2, 7.5±0.5 and 10.3±0.9 ka respectively, belonging to Holocene accumulation. Several faults developed on T₂ terrace of a small river in Xiataiping offset all the strata under the modern loam layer, and the OSL age of the upper stratum is 5.3±0.6 ka. The activity of fault since Pliocene resulted in strong tectonic deformation of the Pliocene sediments, and its property also changed from thrust to dextral strike slip. Seismic phenomena such as seismic wedge, sand vein and soft sedimentary structural deformation are exposed at Xinmin, Gaichang and other trenches and the offset amount is mostly about 1 m. It is considered to be caused by the same seismic event, with an occurrence time of about 28000 aBP and a magnitude of seven.

依据野外调查成果, 研究维西?乔后断裂通甸?马登盆地段晚第四纪活动的地质地貌特征和古地震事件。结果表明, 该断裂段属于全新世活动段, 以右旋走滑运动为主, 全新世以来的水平滑动速率为1.8~2.4 mm/a, 垂直滑动速率为0.30~0.35 mm/a。 玉水坪探槽 揭示的断错地层OSL年龄为5.1±0.6, 5.3±0.2, 7.5±0.5和10.3±0.9 ka, 属于全新世堆积。下太平某小河T₂阶地上发育的多条断层断错现代土壤层之下的所有地层, 被错上部地层的OSL年龄为5.3±0.6 ka。上新世以来的断裂活动造成上新统的强烈构造变形, 其运动性质由逆冲转变为右旋走滑。新民村和盖场等探槽揭露地震楔、砂脉和软沉积构造变形等地震现象, 垂直错距多在1 m左右, 属同一期地震事件所为, 其发生时间约为28000 aBP, 震级达到7级。