右江断裂带落央小段的断层眉脊带探讨

摘要

断层眉脊带在华南地区是一种罕见的构造地貌现象.描述了在上落央发现的断层眉脊带特征,测量了断层露头的几何学特征,利用三维激光扫描技术研究了断层对水系的影响.结果显示:北侧断层眉脊面出露地表至少0.33 m,南侧为1.3 m,并形成了跌水.眉脊面在平面上呈左行右阶的雁列式展布.该露头由南北两组断层组成,它们均为左旋走滑性质,南侧断层在水平方向上左旋错移冲沟5.5 m.讨论后认为:此次发现的断层眉脊带可能是一次古地震或历史地震事件的遗迹.%The fault scarp is a rare tectonic geomorphologic phenomenon in South China.This paper describes the features of the fault scarp that found in the Shangluoyang village,measures the kinematics characteristics of the outcrop of faults,and researches the influence of the fault on the stream by using the 3D laser scanning technology.The results show that,the fault scarp plane exposed at least 0.33 m in the north of outcrop,and 1.3 m in the south of outcrop with waterfall.They are left-order-right stepping an echelon in the plane.The outcrop is composed of two groups of faults.They are all with left lateral strike slip.The fault on the south side of the outcrop offset the stream with 5.5 m in the horizontal direction.At last,the fault scrap zone what reported in this paper may be a trace of one paleoearthquake or history earthquake.