Identification of active fault topography along the Kishtwar Fault, Jammu and Kashmir, Northwest Himalaya, India

Kishtwar region of Jammu and Kashmir, India has been investigated to identify the traces of active faults preserved in the topography of the area. The objectives were achieved by geomorphic mapping with the help of satellite imageries (Cartosat-1 with 2.5 m resolution), detailed geological field investigations, shallow sub-surface geophysical mapping and the optical luminescence dating. Active tectonic landforms mapped in this study include Kishtwar rhombohedral basin, fault scarps, drainage offset, deformed recent sediments, uplifted lacustrine sediments and faulted river terraces. The evidence of active extensional topography reported here is from the compressional tectonic regime of NW Himalaya and is represented by the ~ 10 km long and 2–3 km wide Quaternary basin, interpreted as a tectonic graben. The basin is vaulted by normal faults, where master fault and the antithetic fault show continuous and en echelon behaviour respectively. The presence of normal fault system bounding the basin/graben, lead to hypothesize that the releasing bend of Kishtwar strike-slip fault is responsible for their origin. Detailed field investigation along these faults led to highlight their active nature and future prospects for palaeoseismic investigations. The active nature of these faults is supported by dip-slip movement, fault scarp, fault rupture and displacement in the Holocene and recent sediments. The spatial distribution of these features has been confirmed with the help of Ground Penetrating Radar (GPR) survey. Optically Stimulated Luminescence (OSL) dating of the deformed units demonstrate that the displacement along the Kishtwar fault has occurred between 16.35 ± 2.13 to 13.14 ± 0.91 ka and 13.14 ± 0.91 to 7.89 ± 0.71 ka.