Tracing escaping structure in the Northern Indo-China Peninsula by Openness and remote sensing

Abstract

The Openness based on DEM emphasizes the terrain convexity and concavity. It facilitates the interpretation of detailed landforms on the Earth’s surface. Compared with the layer stacking of ETM+ with less three-dimensionality and visualizability and with indefinite details of linear images in the deep cutting or deep covered region, the Openness is used for accurate interpretation of tectonic geomorphic units and linear structures. In this paper, the ETM+ images (741 RGB) and RRIM based on Openness combined with the field geological investigation are used to trace the escaping structure in SE Asia. The east boundary is Ailaoshan shear zone and the west boundary is Uttaradit-Dien Bien Phu fault, which together form the southwards extruding wedge block. The arc boundary surface of the southern Khorat Plateau is jutted to the north. The NW and NE sides of Khorat Plateau are traversed by Uttaradit-Dien Bien Phu fault and Thakhek-Da Nang fault, respectively, resulting in a blocked escaping structure. The SE margins of Truong Son structure belt and Song Ma structure belt are both arcs jutting to SE. These arc structures clamped by faults or related to the fault on one side indicating the material flow direction obviously, are the most specific manifestation of escaping structures. Moreover, these push units are extruded from south to north successively.