玛多—甘德断裂甘德段晚第四纪活动特征

玛多—甘德断裂是巴颜喀拉块体内部的一条活动断裂。 通过野外调查发现, 在玛多-甘德断裂的甘德段保留有一条较好的地震地表破裂带。 破裂带整体走向NW向, 长约为50 km。 野外获得的最大左旋水平位移7.6 m, 最大垂直位移4 m。 沿破裂带有大量地震活动的遗迹, 地表破裂类型十分丰富。 通过对各种地质地貌现象的调查与分析, 认为该破裂带形成时代较新。 断裂带在地貌上发育有线性排列的垭口、 断层三角面、 断层陡坎、 断层泉、 断错水系、 山脊扭错、 断塞塘、 鼓包等现象。 根据野外考察并结合现有资料分析, 该破裂带可能是该区域内历史上一次较为强烈地震的产物。 据此推断, 巴颜喀拉块体内部的玛多—甘德断裂晚第四纪以来可能有过强烈的活动并至今活跃。

Late Quaternary Active Characteristics of the Gande Segment in the Maduo-Gande Fault Zone

Maduo-Gande fault is an active fault within the Bayan Har block. According to our field investigation, there was an earthquake rupture zone on the Gande segment of Maduo-Gande fault zone. We found that the length of the rupture zone is about 50 km, with the general trend of NW. The maximum sinistral-horizontal dislocation is about 7.6 m and the maximum vertical dislocation is about 4m. A large number of earthquake traces were found along the rupture zone and the surface rupture phenomena were also various. It is believed that the rupture zone with the formation of a relatively new era through the field investigation and analysis on the geological and geomorphological phenomena. A series of linear arranged pass, fault triangles, fault scarps, fault springs, gullies dislocation, ridges twisted, sag-ponds, pressure ridges, et al. exist along the fault. Based on the field investigation and the materials available, we believe that the rupture zone is due to a strong earthquake in the history of this area. And it is inferred that the Maduo-Gande fault in the Bayan Har block had intense activities since late quaternary and may still be active nowadays.