鹤庆-洱源断裂带位于川滇菱形块体中部偏西,四周分别被程海近SN向断裂(带)(东)、丽江-剑川NE向断裂(北、北西)、龙蟠-乔后NNE向断裂(南西)及红河NW向断裂(南)等区域性活动大断裂所围限。根据断裂构造的直接解译标志——清晰的线性形迹和鹤庆-洱源断裂带形成的构造地貌标志如大型/微型断层陡坎、断层谷地、断塞塘等及断裂走滑造成的水系错动、河流阶地面被错及同一盆地边界相邻的多个洪积扇顶的同向扭动等,在高分辨率的SPOT-5(全色波段空间分辨率可达2.5m)及中等分辨率ETM(全色波段空间分辨率可达15m)遥感影像上对鹤庆-洱源断裂带的空间分布、规模、活动性质、相对活动时代及活动幅度进行了遥感分析,并做了详细的野外验证。研究结果表明:1)鹤庆-洱源断裂带基本沿丽江盆地东部东边界、鹤庆盆地东边界、洱源盆地西边界及鹤庆盆地与洱源盆地间的山地段(简称山地段)分布,断续延伸近100km,在盆地边界断层走向近SN向、山地段为NE40°~50°。晚更新世晚期以来洪积扇中前缘微型断层陡坎(高不超过5m)的存在不仅反映该断裂带的最新活动而且也说明活动性有逐渐向盆地内部迁移的迹象,尤以鹤庆盆地东边界最为明显。2)通过SPOT-5遥感影像上洪积扇的色调及几何特征分析,晚更新世早中期的洪积扇广泛分布在各盆地的边界及山地段谷地的两侧,扇形地保存相对完整;晚更新世晚期-全新世早期洪积扇分布较为有限,但扇形地保存十分完整,这两期洪积扇是我们分析鹤庆-洱源断裂带的遥感影像特征及活动性依靠的最主要地貌类型。3)根据断裂带活动性质遥感分析,鹤庆一洱源断裂带主体断裂在盆地边界垂直断错晚更新世早中期洪积扇,地貌上形成一级洪积台地,高出盆地面不超过40m,同时水平?
Heqing-Eryuan Fault Zone lies to the west of the central Sichuan-Yunnan rhombic block and is surrounded by four regional active faults including near S-N Chenghai Fault ( E), NE Lijiang-Jianchuan Fault (N, NW), NNE Longfan-Qiaohou Fault (SW) and NW Honghe Fault (S). According to the direct interpretation marks of the active faults, which are clear linear features and tectonic landforms including macro and micro fault scarps, fault valleys and broken ponds formed by the fault zone and these marks such as the offset streams, deformed river terraces and the same direction twist of the tops of the adjacent alluvial fans group at the same basin's boundary which resulted from the fault stike-slip movement, the spatial distribution, the scale, activity property, relative activity age and active amplitudes of Heqing-Eryuan Fault Zone have been analyzed directly on the high-resolution SPOT-5 (2.5m) and middle-resolution ETM (15m) remote sensing images and detailed field verification has been finished. The research results show that Heqing-Eryuan Fault Zone controls the eastern boundaries of east Lijiang Basin and Heqing Basin and the western boundary of Eryuan Basin and the strikes of mountain ridge lines, valleys and rivers between Heqing Basin and Eryuan Basin strictly and extends about 100kin intermittently. The fault strike is near south-north in the boundaries of the three basins mentioned above and NE 40°~ 50° in the mountain segment between Heqing Basin and Eryuan Basin (called as the mouantain segment for short below). Remote sensing direct identification of micro-fault scarps (the height is no more than 5m) in the middle or front part of the alluvial fans which were formed in the late period of Late Pleistocene can not only reflect the newest action of the fault zone, but also indicate that the activity is gradually moving from the boundary to the corresponding basin interior, especially in Heqing Basin. Through the analyses of color and geometric features of alluvia