沿断裂带的大比例尺地貌填图是活动构造研究的重要基础。传统方法一般通过遥感、航片解译以及典型地点的实地测量进行详细填图。因此传统方法一般只能获得二维变形特征,或者局部的三维变形。激光雷达测量(Light Detection And Ranging-LiDAR)技术优势为对地貌的高精度、全方位、三维直接测量,可以为活动构造研究提供沿整条断裂带的高精度地貌高程基础数据。基于LiDAR数据的量化分析是未来活动构造研究的趋势。目前,美国、欧洲、日本以及我国台湾地区等均已经开展沿主要活动断裂带的大规模机载LiDAR测量。与传统方法相比,LiDAR技术在森林覆盖区和城区的活动断裂填图中具有巨大的优势,在沿断裂位错测量上也更精准,更有效。并且震前与震后LiDAR数据对比也是研究同震变形特征、探索断裂发震模式的重要手段。本文综述LiDAR技术在活动构造研究中的主要应用,介绍LiDAR技术在活动构造研究中的优势与前景。分析表明,激光雷达技术在活动构造研究中的应用势在必行,沿国内主要活动断裂带的机载LiDAR测量将成为未来国内活动断裂研究基础数据获取的重要手段。
Landscape evolution in active orogen region is inevitably affected by landslides associated with strong earthquakes, rain or storm. However, quantitative studies of the orogenic or eroded volumes are rarely demonstrated. The 2008 Wenchuan Earthquake triggered serious landsliding, consequently, a large amount of landslide material. However, the landslide volume is estimated mainly on the landslides areas interpreted in their semi-automated landslide mapping algorithm. However, the total volume of landslides triggered by the Wenchuan Earthquake amounts to 5-10 times bigger than the expected upper bound according to the empirical correlation between ＂total landslide volume＂ and ＂moment magnitude＂. Here we show that the total landslide volume estimation has large uncertainties to be used to determine whether the Wenchuan Earthquake generates or reduces relief. Thus, the widely held view that large dip-slip and oblique-slip earthquakes build mountainous topography may still be applicable to the Wenchuan Earthquake in Longmen Shan area. To challenge this view, simple landslide volume and co-seismic uplift comparison is not enough, i.e., more data are needed.
