DIGITAL ELEVATION MODELS AND GEOMORPHOMETRY FOR GEOMORPHOLOGICAL AND GLACIER ANALYSIS IN THE WESTERN HIMALAYA

Topographic information is required for geomorphological mapping, surface process modeling, and topographic evolution studies. Satellite-derived digital elevation models (DEMs) can be generated from satellite imagery such as SPOT and ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) data, to study the influence of surface processes on erosion and relief production. In the western Himalaya, we have limited knowledge regarding the influence of scale dependent surface processes on the denudational unloading of massifs, and on polygenetic evolutional sequences. Given that the topography can record information about past events depending upon its erosional history, geomorphometry can be used to better understand geomorphic change and surface processes. Our research objectives were to evaluate the influence of river incision and glaciation on relief production. We wanted to determine the influence of river incision and glaciation on various topographic parameters including relief and slope angles. Analysis of the topography included hypsometry, profile and altitude analysis, and one and two dimensional semivariogram analysis. Results indicate that at Nanga Parbat , non-linear geomorphometric relationships are the result of changing erosion processes with altitude and through time. We found that glaciation appears to have the greatest influence on the topography in terms of its spatial influence, relief production and ability to modify the landscape. This finding suggests that glaciation may play a greater role in denudational unloading than previously thought, as large glaciers are known to have eroded major valleys such as the Indus. Collectively, our results indicates that where dramatic geomorphic change has occurred, the landscape in unlikely to be in topographic equilibrium, which permits relief production at a variety of scales.