Litho-tectonic and precipitation implications on landslides, Yamuna Valley, NW Himalaya

An attempt is made to explain the relationship of landslides, litho-tectonic and precipitation regimes. The possible influence of these factors on the dimensional pattern of landslides is also inferred. The Yamuna River valley, NW Himalaya, which traverses the Higher Himalaya (HH) and Lesser Himalaya (LH) rockmass, endures disastrous landslides and hence is taken as the case for study. To infer the objectives, mentioned above, proxies like stream length gradient, topographic profile, steepness index, and ratio of valley floor width to valley height were used to infer a spatially varying tectonic regime, whereas rainfall data and Normalized Difference Vegetation Index were used to determine spatial differences in precipitation and vegetation variability, respectively. The dimensional pattern of landslides utilized landslide area and volume. The higher reaches of the HH and lowest part of the LH show rockfall dominance associated with relatively high tectonic activity, whereas most of the debris slides coincide with regional thrusts. Total area and volume occupied by the landslides are ~1.5±0.16 x 106 m2 and ~4.7±1.2 x 106 m3, respectively. The dimensions of debris slides were found to be less influenced by the litho-tectonic and precipitation regimes, whereas dimension of rockfalls was found to be more sensitive to these conditions.Peer reviewe