Abstract: Correlated evidences about the newest activity of Red River Fault in Vietnam(RRFV),such as seismicity,geology,geomorphology and chronology etc,have been obtained through joint survey along the fault in Vietnam. Our comprehensive studies demonstrate that,the same tendency of gradual weakening of the fault activity from north to south in the part of China since Quaternary has been kept on in Vietnam. The primary active period of Red River Fault in Vietnam is in late of middle Pleistocene,and in general,the active level of Red River Fault is lower prominently than that in Yunnan,China,especially,the activity of RRFV has been very weak since late Pleistocene. The synthesized analysis on seismicity and regional GPS deformation monitoring data indicates that the dynamic impact of so-called lateral extrusion from Tibetan Plateau on the dextral slip of RRFV should be very limited. Furthermore,the possible reasons including geotectonic and deep crustal structure have been discussed in the article.

Key words: Red River Fault in Vietnam, active period, accumulated displacement, geotectonic, deep crustal structure

摘要： 通过中越两国对越南红河断裂带开展的联合野外考察,获取了地震、地质、地貌和年代学等反映该断裂最新活动的相关证据。综合研究表明,越南红河断裂带第四纪以来的右旋走滑活动延续和保持了在中国境内自北向南逐渐减弱的总体趋势。其第四纪主要活动时代为中更新世中晚期,且总体活动水平明显低于中国云南境内部分,特别是自晚更新世以来越南红河断裂带的活动已表现得十分微弱。结合断裂现今地震活动和区域GPS大地形变特征分析认为,自晚第四纪以来,来自青藏高原的"侧向挤出"动力作用对红河断裂右旋走滑活动在时间、空间和强度等方面的影响可能非常有限。文中还探讨了造成这一有限影响可能的大地构造和深部构造原因。

关键词: 越南红河断裂带, 活动时代, 累积位错, 大地构造, 深部构造