Figure 2. (a) SRTM (90 m resolution) color shaded relief map of the Xidatan– Dongdatan segment. (b) East-looking perspective view of the western part of the Xidatan–Dongdatan valley, generated by draping the Landsat Enhanced Thematic Mapper Plus (ETM+) images over Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM). The size of the image is about 40 km wide by 90 km long. The image has 2.5 times vertical exaggeration. Landsat bands 7, 4, 1 (30 m resolution) are used as red, green, and blue, respectively. White circles with numbers correspond to the sites studied by Van der Woerd, Tapponnier, et al. (2002).