Climatic and tectonic controls of erosion in the eastern end of Himalaya
Abstract
The eastern end of Himalaya provides a unique opportunity to examine how climate influences the distributions of landslides and basin averaged erosion in tectonically active mountains. Previous studies in the Himalaya ranges and the eastern syntaxis have focused on how earthquakes and long-term river incision influence the distribution and occurrence of landslides. However, the role of climate on the distribution and rate of erosion in the Himalayas is still debated. In this study, we examine the spatial distribution and characteristics of precipitation-induced landslides and compare them with 10Be-derived catchment erosion rates in the eastern end of Himalaya. We focus on landslides in basins from the rangefront to the Dibang Valley, where precipitation rates vary from 7000 mm/yr in the rangefront to 200 mm/yr in the interior over a distance of 100 km. To do this, we first generate a landslide inventory with a 15 year interval using satellite imagery from November 2002 and 2017. The locations and sizes of landslides are detected from changes in the earth's surface using high-resolution satellite imagery. The total number of mapped landslides is 2500, with areas varying from 370 m2 to 6.7 km2. The spatial variation of landslide density is compared with geomorphic variables such as slope, relief, and elevation, as well as the climatic variable of mean annual precipitation rates. Then, we compare them with thousand-year timescale erosion rates determined from 10Be in detrital sands collected from catchments in the region. Decadal timescale erosion rates from landslides and thousand-year erosion rates from cosmogenic nuclides will lead to a closer examination of how the interactions between climate and tectonics influence landslide processes and in turn influence long-term landscape evolution in the eastern end of Himalaya.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMEP21C2256S
- Keywords:
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- 1810 Debris flow and landslides;
- HYDROLOGYDE: 1824 Geomorphology: general;
- HYDROLOGYDE: 1826 Geomorphology: hillslope;
- HYDROLOGYDE: 4302 Geological;
- NATURAL HAZARDS