LANDSLIDING AND STREAM POWER IN THE VICINITY OF THE TSANGPO RIVER GORGE AT NAMCHE BARWA, EASTERN TIBET

Recent work has explored the relationship between localized extremes of uplift and denudation in the eastern and western syntaxes of the Himalaya. We hypothesize that the rapid uplift is largely accommodated by mass wasting from threshold hillslopes, with the rate controlled by river incision. To assess this mechanism, we analyzed unit stream power (derived from DTED level 1 digital elevation data, TRMM precipitation data and Landsat-derived widths) in conjunction with landslides mapped from Landsat images. Our results show coincidence of high stream power and high landslide density in the vicinity of Namche Barwa in the eastern Himalaya. This is consistent with the hypothesis that landsliding on threshold hillslopes controlled by a rapidly down-cutting river has contributed to anomalously high rates of erosion and uplift in the Namche Barwa syntaxis.