GEOSPATIAL REPRESENTATION OF REGIONAL-SCALE CHANNEL-SLOPE VARIATION ALONG THE HIMALAYAN RANGE

Using channel slope as an indicator of active deformation of the Himalaya, uplifted low-relief areas are identified north of the Main Frontal Thrust. Utilizing SRTM Digital Elevation Models (DEMs) and Geographic Information Systems, variations in channel geometry are emphasized by filtering the surface topography outside the reach of 5th-order streams. The resulting data creates a spatially significant representation of channel elevations along the length of the entire Himalayan range, effectively a three-dimensional channel profile with correlations between channels. This representation facilitates identification of areas within which channels deviate from normal incision geometries. Low-relief areas are identified and described according to their degree concavity and associated concave-up to concave-down knickpoints. These regions are characterized by a shallowing of channel slope and accumulation of sediment upstream of the concave-down knickpoints. Regional variations in channel elevations show a spatial correlation with seismic activity. This work explores the influence of tectonic uplift on the channel geometries and observable lateral variations across range-scale structures.