Analysis of neotectonic structures in the piedmont region of Pir Panjal Range NW Himalaya by integrating geomorphic indi
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Analysis of neotectonic structures in the piedmont region of Pir Panjal Range NW Himalaya by integrating geomorphic indicators coupled with geophysical transects (GPR) Bikram Singh Bali1 · Ahsan Afzal Wani1 Received: 5 August 2020 / Accepted: 11 November 2020 © Springer Nature B.V. 2020
Abstract Ground-penetrating radar (GPR) survey was performed at ten potential sites to delineate the blind surface ruptures, structural discontinuities/shallow subsurface active faults and palaeoseismic deformation in the dynamic range front environment of Pir Panjal. A total of 20 GPR profiles were recorded in four districts with the unshielded 100 MHz rough terrain antenna system and 250 MHz shielded antenna, and out of them, 10 profiles were processed and correlated with detailed structural and lithological map of the area. Several tectonic landforms such as strath surfaces, uplifted fluvial terraces, fault scarps, structural discontinuities, offset ridges, meanders, linear valleys and liquefaction structures mapped during field exercises were meticulously examined by GPR prospecting. Steeply dipping hyperbolas, warped and inclined radar reflections that sharply cut or offset stratigraphic reflections correspond to thrust fault strands. The processed data unearth normal and reverse faults, as well as liquefaction structures covered by recent deposits. However, their correlation with geological and structural data gave a more precise insight into the structural settings of the studied area. The different discontinuity relations specified in the Karewa deposits are mainly due to the regional compressional stress regimes and gradual anisotropic lithology prevailing in the area. The GPR data in agreement with the exposed geological units and structural models suggest that bulk of the landscapes have been evolved/sculptured under the influence of compressional and extensional tectonics along the concomitant active faults. The structural discontinuities (Faults) and the mechanical properties of Karewa deposits will be useful to infer the neotectonic activity prevailing in the area. The whole study would be helpful for the seismic hazard assessment of parts of the Kashmir Valley, NW Himalaya. Keywords Ground penetration radar (GPR) · Karewa deposits · Kashmir Valley · RTA · Neotectonics · Seismic hazard assessment
* Ahsan Afzal Wani [email protected] 1
Department of Earth Sciences, University of Kashmir, Srinagar, India
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Natural Hazards
1 Introduction Active faults and their investigation in seismically active regions are vital for understanding tectonic activity and seismic hazard in existing stress regime (Bilham et al. 2010; Schiffman et al. 2013; Bilham and Bali 2013; Bhaskar et al. 2014; Kundu et al. 2014; Bhat et al. 2016, Yousuf and Bukhari 2020). Apart from geological-geomorphic mapping, ground-penetrating radar (GPR) surveys have been successfully applied in the present study to trace and map active faults and liquefaction structures in the subsurface formation (Rasheed et al. 2003; Ferry
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