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Geospatial techniques play a crucial role in geomorphic studies, particularly in the challenging terrains like mountainous regions, inaccessible areas and densely vegetated landscapes, where geomorphic features cannot be recorded easily. Tectono‐geomorphologic observations provide important clues regarding the landscape evolution, morpho‐dynamics and ongoing tectonism of the region. The present study has been carried out in the Zanskar Basin (ZB), located to the south of the Indus Tsangpo Suture Zone (ITSZ), in the hinterland of the NW Himalaya. This study has been carried out to assess and evaluate active tectonics by employing tectono‐geomorphic analysis, dynamics in drainage networks, geomorphological field observations and the Geographic Information System (GIS) environment. High‐resolution satellite images, topographic maps and the Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) were used to generate primary data sets, which were corroborated with field investigations for valid inferences. The geometry of the ZB suggests that continuous tectonic activity exerts first‐order control on the overall shape, size and structure of the ZB. This first‐order response is clearly reflected in the landforms modified by tectonic processes, namely, linear mountain fronts, elongated shape and tilting of the basin, braided and meandering river courses and lower stream length gradient index values in hard rock terrain. The ZB exhibits several eye‐catching geomorphic features, such as well‐defined triangular facets with wide base lengths and wine‐glass valleys with small outlets along the footwall block of the Zanskar Shear Zone/South Tibetan Detachment System (ZSZ/STDS), as well as the presence of wind gaps, water gaps, bedrock incision, incised and entrenched valleys, narrow gorges and a high incision rate inferring active tectonics and recent uplift in the region. In addition, the existence of uplifted river terraces, as well as the stepped morphology of fans and strath terraces, suggests that the region is experiencing recent activity and ongoing tectonic uplift. These modified geomorphic characteristics suggest that the hinterland, which is part of the NW Himalaya, is tectonically quite active and has experienced a differential rate of tectonics during its evolution. The quantified geomorphic indices and their relations with the tectonics, climate and erosion activity infer that the basin geometry is mostly controlled by the ZSZ/STDS that dips 20°–70° NE, the south‐dipping Zanskar Counter Thrust (ZCT) and other local tectonic elements like the Choksti Thrust (CT), Stondgey Thrust, Zangla Thrust and tectonic structures. The synergised results of quantified geomorphic indices and tectono‐geomorphic evidence in the ZB strongly indicate that both the past and ongoing tectonism have significantly shaped and modified geomorphology of the ZB. [ABSTRACT FROM AUTHOR]

This study deals with the seismicity analysis of north Pakistan and its surrounding regions (Pamir, Hindu Kush, Karakorum, Kohistan, and Himalaya). For the seismicity analysis, earthquake catalogue is updated and homogenised which reports 14,158 events with magnitude M ≥ 4 from 1900 to 2021. Based on updated catalogue, the seismicity of the study region is analysed with respect to (1) various subdivisions of dataset (Subsets 1–6 based on time-institute), (2) domains based on tectonic setting or tectonic structures that include Pamir, Hindu Kush, Karakorum, Kohistan, and Himalaya, and (3) depth zones (zone-1 0–70 km, zone-2 70–150 km, and zone-3 150–300 km) based on available data and previous study. The various subsets give us Mc4.4–5.8, a value 6.5–13.5 and b value 0.73–1.89. The appropriate Mc for the whole region using various subsets is 4.9, because 4 subsets give this value, and is the average value of subsets. Period from 1900 to 1963 were identified as the low seismic activity period with a value 6.55, and subset 4 (2006–2021) the most active seismic period with a value 13.5. Pre-instrumental period (1900–1963) is dominated by large earthquakes (b value 0.73), while instrumental period (1964–2021) is dominated by small magnitude earthquakes (b value 1.77). Domain-wise Pamir, Hindu Kush, Karakorum, Kohistan, and Himalaya produced a value 11.151, 10.012, 8.091, 9.685, and 6.709, while b value 1.63, 1.36, 1.12, 1.52, and 0.86, respectively. Relatively, the lower b values of Hindu Kush, Karakorum, and Himalaya are due to thrust faults, which reveals that these are high stresses domains and dominated by moderate-to-large magnitude earthquakes. Spatially, Hindu Kush, Karakorum, and Pamir have high variation in b value (Hindu Kush 0.5–2.5, Karakorum 1.2–2.8, and Pamir 0.5–2) and large magnitude earthquake are expected in these domains. The lower b value regions (dominated by large magnitude earthquakes) are south-west of Pamir, the central region of Hindu Kush, Karakoram (almost the Pak-Afghan border), Nanga-Parbat-Haramosh, Hazara-Kashmir Syntaxis, and Kohistan Island Arc. In the depth zones of Pamir, Hindu Kush and Karakorum zone-3 of Hindu Kush and Zone-1 of Karakorum are seismically less active zones and has experienced moderate magnitude earthquakes. Kohistan and Himalaya are characterised by shallow earthquakes, but variation of b value (0.9–1.6) in the Himalaya suggests high stresses. Zone-3 (150–300 km depth) under the Pamir, Hindu Kush, and Karakorum is the zone of large earthquakes and causes deaths and damages in north Pakistan, Afghanistan, and Tajikistan. Also, in zone-1 of Pamir, the low b value approximately less than 1 in the central part of Pakistan–Afghanistan and Tajikistan border reveals that shallow seismicity also causes destruction in these countries. [ABSTRACT FROM AUTHOR]

Protracted interseismic locking of the low‐angle décollement of the Himalaya causes strain accumulation and results in growing slip deficit with time. Unlocking the frontal splay of the décollement during high‐magnitude earthquakes (Mw ≥6.5) may cause surface ruptures along the Himalayan Frontal Thrust (HFT). According to Paleoseismic investigations and observations on undeformed fluvial strath surfaces, the HFT in Nahan Salient has not experienced coseismic slip at least for the last six to seven centuries. Our new observations and chronological assessments on folded and faulted fluvial strath surfaces on the hanging wall of the HFT indicates a maximum slip rate of 10.4 ± 0.8–12.2 ± 0.8 mm/a (averaged over the last 7–8 ka). Seismic quiescence of 600–700 a results in a ~6.2–8.5 m slip deficit on the HFT which could trigger a Mw ≥7.7 earthquake. Our findings underline an enormous seismic risk prevailing in the Nahan area. [ABSTRACT FROM AUTHOR]

The Mat Fault situated in the Eastern Himalayan Fold Belt was mapped around Mizoram and is oriented NNW to SSE. This region has experienced a number of earthquakes in the recent past that damaged settlements and triggered numerous landslides. A set of geomorphic parameters were analysed on both sides of the Mat Fault to understand the tectonic setting. The six geomorphic parameters include: elongation ratio, hypsometric analysis, asymmetry factor, transverse topographic symmetry factor, stream length‐gradient index, and valley floor‐to‐width ratio, and they were calculated for 20 fourth‐order sub‐watersheds. Out of 20 sub‐watersheds, 10 sub‐watersheds were selected from the northern block and 10 from the southern block. Hypsometric analyses show that all the sub‐watersheds have attained a mature stage of geomorphic cycle of erosion; and from the analysis of hypsometric curves, it is found that 16 of the sub‐watersheds might have been uplifted due to tectonic activity. The asymmetry and transverse topographic symmetry factor values also suggest tilting in different directions possibly due to obstruction by faulting. The anomaly of high stream length index values is also observed in different sub‐watersheds indicating neotectonic activity. Low values of the valley floor‐to‐width ratio (<0.5) suggest V‐shaped valley topography, which indicate vertical incision due to tectonic activity. On evaluating relative tectonic activity among 20 sub‐watersheds, it is found that 80% of sub‐watersheds in the northern block show relatively stronger tectonic activity than the southern block. The present work suggests that the study area is tectonically active, and the possibility that they were produced by seismic activity. [ABSTRACT FROM AUTHOR]

Across the Himalayan foreland area, alluvial fans respond to fluvial depositional landforms created by active tectonics and are incorporated within hydro-sediment processes. Each tributary of the master stream has its water and sediment to discharge, which assists in initiating several mesolevel fans in response to the active tectonics in Jaldhaka basin. Along the mountain front, active MBT (Main Boundary Thrust), MFT (Main Frontal Thrust) and lineaments (parallel and transverse to Himalaya) have governed the tectonically active Quaternary foreland area where numerous meso-level fans have developed. The study aims to estimate the tectonic activeness of each meso-fan using the morphotectonic indicators. The tributaries of the Jaldhaka River are permuted to the recent tectonism or neotectonics to form each meso fan with its basin displaying the varying degree of their activeness and aggradation system. Statistical methods like technique for order performance by similarity to ideal solution (TOPSIS) and VIKOR (Vlse Kriterijumska Optimizacija Kompromisno Resenje) that specify multicriteria optimization and compromise solution, in Serbian have ranked the Fan 2 as mostly active and Fan 4 is comparatively tectonically stable. The hydro-sediment characteristics reveal the topographic spatial dynamics of Fan 4 where lobe 3 has elevated from 1984–2014. The XRD analysis specifies the scientific key in response to the dominance of dolomite in the aggraded elevated bed sediments carried by the Rohtikhola River. The conceptual fan models of Fan 2 and 4 display the fan development phases through four stages. It has clearly defined the extension of the fan lobes of Fan 2 and 4. It is summarized that within a common climatic zone and similar neo-tectonic setting, meso-level fans have differential morphotectonic signatures with dynamic aggradation processes. [ABSTRACT FROM AUTHOR]

Recent studies reveal that the Peshawar Basin, in the northwestern region of the Himalayas, is actively deforming in response to the ongoing tectonics of the Himalayas. Geological research on the Peshawar Basin has been limited despite thousands of reported low to moderate-magnitude earthquakes over the past two decades. After analyzing the Digital Elevation Model (DEM), seismic data, and geophysical data along with field observations, we have been able to identify six active faults that extend from the Southeast to the Northwest. Between 1978 and 2018, several earthquakes with a magnitude greater than 5 indicate neotectonics activity in the Peshawar Basin. Previous research has identified active faults only in the southern region of the Basin. This study presents a comprehensive mapping of active faults in the Peshawar Basin. These identified faults cut through the towns with the highest population density, given that the Peshawar Basin has only 10% of the exposed rocks. Field observations and fracture data from various infrastructures confirm that the Ghorghasti and Pir Sabak faults are thrust faults, while the Charsadda-Takhbhai, Mardan, Pir Piai, and Swabi faults are normal faults. Moreover, the alluvial deposits show normal faults and anticlinal folds, indicating widespread active deformation along these fault lines. [ABSTRACT FROM AUTHOR]

The study of earthquake precursor is being accomplished throughout the world based on observations of ground and ionospheric parameters. The Multiparametric Geophysical Observatory (MPGO), Ouguri Hills, Tezpur (Eastern Himalaya) is an avenue for identification of earthquake precursor. In the article we discuss on the seismic induced ground as well as ionosphere based precursory phenomena in the different geophysical parameters. Apart from seismic induced perturbation there exist perturbations due to inter-planetary, terrestrial, hydrological, and tectonic sources. Statistical, mathematical techniques and models are applied to discriminate the extraneous noises for identification of the seismic induced anomalies. Earthquake precursory phenomena can be correlated to deformation occurring close to fault preceding the main shock. There are evidences that seismic induced anomalies in physical sense to be actual. The present investigation also evince that seismic induced anomalies in geophysical parameters are persuasively real in the sense that these are physically related to the preparation and generation processes of imminent seismic activity. The Multiprametric Geophysical Observatory in Ouguri Hills (Tezpur) is an opportunity for better scrutinizing seismic precursor from long term temporal observations of the parameters. [ABSTRACT FROM AUTHOR]

The collision of the Eurasian and Indian plates has resulted in two spatially offset subduction zones, the Makran subduction zone to the south and the Himalayan convergent margin to the north. The Main Mantle Thrust (MMT) and adjoining regions have a complex geomorphic setting and geological variations with a number of active faults that were connected with numerous major devastating earthquakes in the investigation. Our study was carried out to develop a DEM based geomorphometric approach to study the stream power model and hypsometric analysis along the MMT and surroundings to achieve rigorous investigation of its potential to delineate active topography. Active tectonics in this region has greatly influenced the drainage system and geomorphic expressions. The study area is a junction of three important mountain ranges (Hindu Kush-Karakorum-Himalayas) and thus is an ideal natural laboratory to investigate the relative tectonic activity resulting from the India-Eurasia collision. Morphotectonic and geomorphometric evaluations of the MMT and surrounding regions were conducted by associating various DEM derived geomorphometric indices such as steepness (Ks), hypsometric integral (HIs), Hack gradient index (SL) and concavity (θ). From the results obtained, we deduce that these combined procedures reveal the highly active deformed zones connected to neotectonics. Ground validations and Landsat satellite imagery also give clue about the active faults based on the offsetted channels, triangular facets and severely deformed topography. [ABSTRACT FROM AUTHOR]

Central Asia exceeds neighboring territories in the intensity of Quaternary uplifts and active faulting. The active fault kinematics differ in the northeast of the region, from Middle Tibet to Eastern Sayan, and its southern and western parts, including the Himalayas, the Pamir–Punjab syntaxis, and the region north of Gorny and Mongolian Altai. The northeast is dominated by latitudinal left-lateral strike-slips, while the south and west, by right-lateral strike-slips and northwest- and latitudinally striking overthrusts. The features of active tectonics are governed by the upper mantle structure, studied in three horizontal sections. The highest mountain systems, with sharply reduced P-wave velocities and lower rock densities, are distinguished in the section 67 km deep (crust/mantle boundary zone and upper lithospheric mantle). Dilatation became the main reason behind the intensive uplift of these mountain systems and, partially, Tibet. The sections with depths of 158 and 293 km revealed heterogeneous structures of the upper mantle of Central Asia. In its eastern part, P-wave velocities were significantly reduced by the influence of Tibetan and Khangai intramantle plumes. Here, lateral extension exceeded lateral shortening, and the lithosphere could not transfer the pressure of the Indian Platform to the northern tectonic zones. Dilatation of the upper mantle caused the uplift of Tibet and the Khangai Plateau. Plume-related currents in upper mantle caused left-lateral strike-slips along latitudinal faults. In the south and west of Central Asia, P-wave velocities and the density of the upper mantle increase. In the south, the lithosphere of the Indian Platform thickens and underthrusts the Himalayas and Southern Tibet. Active thrusts, right-lateral strike-slips, and oblique-slip thrusts in the western and northwestern parts of Central Asia express horizontal compression of lithospheric blocks. The heterogeneous density of the lithosphere resulted in rotation of the compressed blocks, so that shear decreased and even faded along the faults. [ABSTRACT FROM AUTHOR]

Generation and interpretation of geomorphometric maps through remote sensing and GIS techniques are significant platforms for the investigations of neotectonics. This investigation presents data from the Nanga Parbat Syntaxix (NPS) and its neighborhood, which is one of the fastest rising portions of the orogen (8‒10 mm per year). Geoscientists and geomorphologists frequently generate huge datasets and a significant amount is spatially distributed over space. The Trend Analysis of Polynomial Surface (TAPS), Local-Base-Level (LBL) and Vertical Dissection (VD) maps were generated from SRTM DEM. The investigation area is situated along the MMT and below MKT along the Indus River in Gilgit-Baltistan, Northern Pakistan, containing five major geomorphometric units, two describe by drainage dissection, two of relative relief, with an escarpment of thousands of meters, and a relatively flat Deosai plateau in the southeast portion with large VD of the terrains. The residual map was obtained from DTM minus 12th order trend surface that delineates areas of abnormal elevation to check spatial correlation with the other geomorphometric maps. The 12th-order Trend Surface is the best representative surface that reflects NE‒SW and NW‒SE upward-trend surface of Nanga Parbat Haramosh Massif Zone (NPHMZ). The Sassi Raikot Fault Zone (SRFZ), NPHMZ, MKT and region northwest of Jaglot towards Hindukush in the investigation area fits well in terms of anomalous elevations, where as Deosai plateau, Skardu, Kachura, Gorikot (Astore valley), Jaglot and Gunar regions reflects relatively negative anomalies. The LBL map generated through 2nd and 3rd Strahler order streams has decoded excellent results. Isobase and VD results show higher values near NPHMZ, MKT, and upper Astore valley. The axis of the NPHMZ and MKT corresponds with positive anomalous elevation of the residual map and is consistent with the regional neotectonics and uplift. [ABSTRACT FROM AUTHOR]

Khadg Singh Valdiya, a stalwart amongst Indian geoscientists is widely recognised and highly respected for his pioneering works on Himalayan geology and environment. Besides being a recipient of the highest Civilian Awards: Padma Shri and Padma Bhushan, he was the awardee of numerous prizes, awards, honours and fellowships [1]. His significant contributions to the stratigraphic, structural and tectonic evolution of the Himalaya laid the foundation for several ongoing studies in the Himalaya. Valdiya also made noteworthy contributions to the tectonic rejuvenation of the central Sahyadri mountains, and the origin and disappearance of the prehistoric Saraswati river in northwest India. Valdiya wielded enormous influence on the Indian geoscience academic community through the many books that were authored by him on Indian stratigraphy, Himalayan geology, the Saraswati river, neotectonics of the Indian sub-continent, and environmental geology. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Paglajhora area, located in the southeastern part of the Kurseong town in the Darjeeling Himalaya region, India, experiences frequent slope failure especially in monsoon season. Due to the intricate disposition of major thrust zones (MCT, MBT, etc.), heavy rainfall, neotectonic and anthropogenic activities, etc., the cause of slope failure is not similar all over the area, which makes difficult to categorize the landslides based on their mode of failure. The present work is aimed to demarcate the landslide-prone areas from the surface displacement (horizontal) map derived by optical image correlation (OIC) technique applying normalized cross-correlation (NCC) algorithm of two temporal Landsat 8 OLI (level 1TP) images, supported by the ground field survey. Results indicate that the overall range of surface displacement (horizontal) rate in the study area varies from 0.4 to 8 m/year out of which the range 0.5–1.5 m/year being dominant classifying the slide type as slow-to-very slow earth flow with a velocity class varying from 3 to 2. Places showing relatively higher displacement values (3 to 8 m/year) match accurately with the already reported slide zones and the large exposed scarp surfaces noticed during the field surveys or distinguished from the satellite imagery. Areas with lower displacement rates (< 1.5 m/year) experience very slow earth flow, which are confirmed by the presence of cracks and steps on the major roads. Depths of shallow subsurface slip planes are established from dipole-dipole geo-electric surveys in few locations showing moderate surface velocity. [ABSTRACT FROM AUTHOR]

This paper focuses on the analysis of geomorphic landform development, particularly between the Trans Himadri Fault and the Main Central Thrust including Berinag Thrust and other major NNE–SSW and NW–SE striking faults/thrusts in the Higher Central Kumaun Himalaya. Digital analysis of remote sensing data, field investigations including drainage analysis, and development of landforms have been carried out to understand the morphotectonic evolution and, thereby, the neotectonics in this region. A number of morphometric indices [(stream length‐gradient index (SL), steepness index (ks), Chi (χ)] were computed together with knick point analysis. Offsetting of the major river and tributaries was observed along a NNW–SSE direction. Other tectonic landforms, including truncated saddles and disturbed terrace patterns, show that the area is presently undergoing active deformation. The valley floor morphology in the vicinity of the major thrusts provides evidence for aggradation of recent fluvial activity. Developments of various neotectonic features, such as starth terraces, off‐streams, truncated saddles, disrupted terraces, and palaeolake deposits, are evidences for recent tectonic activities associated with the major thrusts/faults. Cut‐and‐fill terraces with thick alluvial cover, debris‐flow terraces, and alluvial fan terraces are significant aggradational landforms observed within the valley that provide signatures of past climatic records. Our study reveals that the fluvially modified debris‐flow terraces were formed between 5 and 20 ka. We infer that the major phase of valley‐fill happened between 5 and 12 ka, whereas the youngest phase of aggradation may have responded to the Holocene tectonic activity that took place around 5–6 ka. The study is significant to understand the recent geomorphic development and tectonic deformation in the study area and may be helpful for future infrastructural development in the region. [ABSTRACT FROM AUTHOR]

Globally the remote sensing and geomorphometric analysis are frequently used for the assessment of tectonic activity. We used satellite-driven DEM data to analyze regional scale fluvial landform development in the parts of the central section of the Indo-Nepal Himalayan mountain chain, which is attributed the active deformation along the strike of major thrust. This deformation is accompanied by coexisting river incision and base-level fall along the longitudinal river course. These anomalies are obtained through conventional geomorphic parameters namely, stream-gradient index (SL), and steepness index (Ks) along with a new method called river Gradient Length Anomaly (GLA) analysis. GLA is a lied to deduct surface uplift and subsidence at the intersection between drainage basin and active thrusts. The deviations (offset) occurred along the river course are attributed to long-term active tectonic movement along thrust/fault or because of erosion/sedimentation processes. We analyzed 16 south-flowing rivers (e.g. Sarda, Kauriala, Girwa, and Babai), across the major Himalayan thrusts such as Main Boundary Thrust (MBT), Ramgarh Thrust (RT) and Himalayan Frontal Fault (HFT). The computed values of SL along the longitudinal course of these rivers range between 0.9‒4153 and Ks ranges from 0.1 to 173. The anomalous rise of SL and Ks values close to the major thrust points toward ongoing tectonics in the basin. The estimated results of fault parameters show that the horizontal shortening is higher than the vertical uplift. The empirical relationship of slip rate along the fault segments is estimated as 1.21, 2.65 and 1.084 mm/y respectively. Based on fault parameter, and abnormal GLA, SL and Ks analysis, and slip rate, a new E‒W oriented active fault structure have been inferred, which passes through the Beldandi, Bilsan, Bachua, Nandgaon, Dhagadhi Surat Nagar, and Bhagwanpur locations. The combined results of the present investigation can be used for evaluation of seismic hazard in the central section of Indo‒Nepal Himalayan front. [ABSTRACT FROM AUTHOR]

Landforms developed along the Main Boundary Thrust (MBT) and Himalayan Frontal Thrust (HFT) zones in Ramnagar area of Kumaun sub‐Himalaya are studied. The geomorphic analyses suggest their spatial and temporal relationship with the reactivation of the boundary thrusts, faults, and associated later developed transverse faults. Mapping of geomorphic features and structural analysis of the MBT and HFT established an intimate relationship between thrusting of rocks along these major thrusts and evolution of landforms. The reactivations of the MBT and HFT have resulted in recent rejuvenation of landscapes formed in the thrust zones. In the MBT zone, the swerving of the channels, linear development of elongated depressions, sudden topographic breaks, and presence of relatively fresh‐looking escarpments, uplifted present ground surfaces, V‐shaped valleys, and occurrence of linear series of dormant and active landslides are observed. Along the Kosi River section, the vertical‐dipping Neoproterozoic Lesser Himalayan rocks have overridden the recent landslide debris along the subsidiary steep reverse faults associated with the MBT. The HFT is topographically represented by an escarpment trending ESE‐WNW along the Himalayan mountain front. In the HFT zone particularly at Ramnagar area, four levels of terraces are noted, the highest being a strath terrace. The surface trace of the HFT is offset by a transverse N‐S trending Ramnagar Fault, which coincides with the course along which Kosi Rver flows. Uplift of the hanging wall block near the HFT has resulted in subsidence of the present ground surface towards the northeast away from the HFT trace. During this process, the transverse streams have vigorously incised the uplifted surfaces. Rivers and streams realigning with the bedrock structure suggest tectonic control on morphology of drainage patterns. Neotectonic activity along the intra‐Siwalik thrust has offset a terrace surface into two surfaces that are separated by a fault scarp of about 50 m high. The bedrocks in the HFT region are gentle to steep dipping towards NW/NE/ESE. Both normal and reverse faults are recognized in the bedrocks. The general trend of the lineaments, which are concentrated in the thrust zones, is E‐W. Two transverse faults trending nearly N‐S cut and offset the HFT. Tectonic activity during the deposition of the Upper Siwalik rocks is evident from the occurrence of liquefaction features. Soft‐sediment deformation structures are observed in fine‐ to medium‐grained friable sandstones. These include up‐welled structures (with vertical to inclined bedding planes), sand dykes, faults (reverse and normal), folds, pseudo‐nodules, and deformed laminations. [ABSTRACT FROM AUTHOR]

The NE–SW trending Mahendragarh–Dehradun Fault (MDF) is a basement fault in the western Ganga plain. The earthquake (4.7 mb) epicentered on this fault on 2nd June 2017 was focused around 10 km depth and does not show any surface rupture. Ground Penetrating Radar (GPR) survey around the epicenter detects few shallow-depth subsurface normal faults parallel to the MDF. However, it is unclear whether these normal faults are linked with the 2017 earthquake or other previous earthquakes. Seismic record (USGS) since 1975 to 2017 suggests occurrence of 22 earthquakes (~ 5 mb) around the MDF and majority (~ 63%) of these are clustered around Delhi and Rohtak. Following the 2017 earthquake, frequency of earthquakes occurence sharply increased than previously recorded instrumentation period from 1975 to 1995. Majority of the seismicity is focused around 10 km depths, shallowing to depths of 25–207 km recorded from 1975 to 2004. Earthquakes clustered along the Main Himalayan Thrust (MHT) shows similar temporal trend as near the MDF. Southward thrust movement of the Himalaya orogenic wedge predicts to impose strike-slip motion on the orthogonal-oriented steep basement faults, which is consistent with geologic and geomorphic field relations, and seismicity focal mechanisms along the MDF. The observed upper crustal deformation associated with such fault deformation pattern may be partly influenced by the MDF and partly by the foreland bulge seismicity. Potential tectono-geomorphic parameters and soil-chronosequence may suggest the surface deformation is active through the Holocene. [ABSTRACT FROM AUTHOR]

The main objective of this paper is to work out quantitative measurement of various geomorphic parameters as well as analysis of geomorphic landforms to study the tectonic character of Suru basin. Morphometric analysis, being widely used to assess the drainage characteristics of the river basins, has also been found to be a useful tool to delineate tectonically active zones. A number of parameters including the mountain front sinuosity, asymmetry factor, transverse topography symmetry, hypsometry, longitudinal profile and the shape parameters have been used. The low mountain front sinuosity values < 1.4 indicate that the tectonic forces dominate over erosive activity. Also the asymmetry factor 66.98% suggests that the right side of the basin has experienced uplift with the development of unpaired river terraces. Hypsometric integral 0.96, convex up hypsometric curve and the GPS data of year 2011–2013 indicate that the relief of the basin is high relative to mean, is in youthful stage and actively uplifting at the rate of 2.18 ± 0.99 mm/year. The shape parameters further suggest that the Suru river basin having lower elongation ratio is indicative of elongate shape of basin with tectonic forces outpacing the erosion power. Area-altitude analysis of the Suru river basin indicates that about 72% of the area of the basin is steeply to very steeply sloping and 28% area is moderately to gently sloping. The area-altitude indicates 72% area of basin could slide when there is slight shift in terms of tectonic disturbance. In addition to the geomorphic indices, the field investigations reveal tectonically unstable character, exhibit a complex topography and varied Quaternary sedimentation. The major geomorphic landforms viz., alluvial terraces, alluvial fans, debris cone, scree, and talus cone at the foothills are present throughout the valley with tectonic structures like micro folds, back-tilted beds, deeply incised valleys, faults and tectonic deposits (Ophiolites), indicating that the tectonic activity has affected the basin. The synergized results of geomorphometry, field investigations and GPS data indicate that the Suru basin is tectonically active and uplifting. [ABSTRACT FROM AUTHOR]

Identifying active faults in alluvial plains with varying sedimentation rates, erosion, and extensive anthropogenic modifications is challenging. In tectonically active foreland basins, tectonics outweighs other controlling factors and produces a set of key fluvial geomorphic markers that are critical for precisely locating active faults. This study employs several key tectonic fluvial morphometric parameters, seismically induced soft-sediment deformation structures (SSDS) as seismites, and the displaced rocks of the Siwalik mountains to mark the surface positions of a buried basement fault system, namely the Great Boundary Fault (GBF) beneath the alluvial cover of the Indo-Gangetic foreland basin. The Great Boundary Fault (GBF) is a NE-SW trending, oblique-slip, branching reverse basement fault running from peninsular India to the Sub-Himalayas. About 400 km length of its NE segment is buried under thick sediments of the Indo-Gangetic foreland basin. This fault's surfaceward propagation deforms the overlying sediments via a network of subsidiary faults, resulting in 20 km wide broad fault zones. The extreme flatness of the Ganga plain conceals the primary faulting evidence but tectonic fluvial geomorphic signatures, the SSDS, and the laterally displaced Siwalik rocks, including south-verging thrusts at the frontal Himalayas, provide collective evidence of neotectonic activity along both fault branches. The primary objectives of this study are to characterise the GBF's buried segment in the Ganga plain through the geomorphic signatures and SSDS, to elucidate its extension up to the Main Boundary Thrust (MBT), and to understand the surfaceward propagation mechanism of its reverse faults through the alluvial-fills. Tectonic geomorphic parameters such as sinuosity spectra and knickpoints were analysed using ArcGIS and Matlab. Meander scar mapping was carried out using Google Earth Pro and Landsat imagery within ArcGIS to characterise the pattern of avulsions and adjustments of the floodplain linked to the tilting directions of the fault blocks. Fourteen prominent knickpoints of 4 to ≥6 m height were derived from the river profiles across the fault zone. Rivers on the up-thrown block possessed low sinuosity (as low as 1.1), whilst those on the down-thrown block had higher sinuosities (up to 3.1), indicating active uplift and rapid subsidence. The deflection of multiple river courses (Ganga, Ramganga, Burhiganga, Sot, Pangaili, and Deoha) and the presence of asymmetrical meander-belts demonstrate an eastward tilting of the tectonic block. The occurrence of liquefaction-induced SSDS close to the GBF corroborates its recent seismogenic nature. Field observation suggests these SSDS are likely related to the Usawan paleo-earthquake (estimated magnitude of 6.5–7.2), epicentered near the GBF. Based on the geometry and the venting characteristics, a new type of SSDS has been recognized, and the term "liquefaction vents" has been proposed for it. Their association with the other types of SSDS that are characteristically formed by >6.5 magnitude earthquakes suggests it is the minimum magnitude of earthquake required for the formation of liquefaction vents. The regional seismic record suggests a significant number of both large and moderate earthquakes around this fault. Finally, we synthesise the results to propose a growth model for the propagation of reverse faulting from the underlying basement bedrock through to the alluvial sediments and the surface of the Ganga plain. [Display omitted] • The Great Boundary Fault is a dextral strike-slip dominated reverse basement fault. • Sinuosity spectra, knickpoints, meander scars & offset streams demarcate the fault. • Liquefaction structures suggest an unreported large paleo-earthquake at Usawan. • Geomorphic signatures & seismites decipher reactivation of the Great Boundary Fault. [ABSTRACT FROM AUTHOR]

The interplay of tectonics, climate and erosion has been proposed as the driving factor behind the growth and evolution of the Himalaya. In this review paper, we focus on the neotectonic deformation history within the southernmost morphotectonic sector of the Himalaya (the Sub-Himalaya) through synthesis of geomorphic data. The Sub-Himalaya is arguably consuming ∼100% of the total Himalayan shortening since early Quaternary. We compiled geodetic shortening rates, paleoseismic events (historical earthquakes), shortening rates deduced from uplifted strath/fill terraces and shortening rates from balanced cross-sections from the north-western, central and eastern Himalayan compartments to obtain an orogen-wide perspective of Quaternary deformation. We supported the compiled data with topographic swath, longitudinal river-profile analysis and ks n plots of the existing drainage in those compartments. Review of the existing data shows a mismatch of the trend of the geodetic shortening rates with those of the millennial or longer timescales; however, Holocene and modern day-shortening rates are of same range (∼14–21 mm a−1). Quaternary shortening rates are much lower, probably due to a longer time-averaging. Except central Nepal, the other sectors show significant out-of-sequence thrusting (∼50% of the total) within the Sub-Himalaya since the Holocene. Paleoseismic data show variable recurrence intervals of large earthquakes along-strike (∼100–600 years) and large seismic gaps or slip-deficit sectors, which could potentially cause surface-rupture earthquakes in the future. [ABSTRACT FROM AUTHOR]

The Himalayan Frontal Thrust (HFT) is the southern-most boundary of Himalayan mountain belt. It represents a zone of active deformation between the sub-Himalaya and Indo-Gangetic alluvial plain. Morphometric analysis of five sixth order drainage basins along the HFT has been carried out for evaluating relative tectonic activity of the region. Based on the combination of various geomorphic indices such as drainage basin spatial asymmetry, drainage gradient, drainage cross profile and mountain front sinuosity indices, the relative tectonic activity in and around the test site drainage basins was evaluated. Where all the indices are not in agreement, the relative importance of the geomorphic indices was considered to evaluate relative tectonic activity which was then compared with the abundance of drainage anomalies and previously reported active tectonic features (including active faults and fractures). Finally, the results were corroborated with the spatial frequency distribution pattern of previous seismicity (>2.5 Mw). Geophysical investigation by multi-frequency, bi-static ground penetrating radar (GPR), conducted at selective locations in the piedmont-alluvial region of Solani and Markanda drainage basins, supports active deformation of sub-surface sediment layers. Well-defined offset and warping of near-surface sediment layers indicating the presence of active fault and deformation of sediment layers were observed in 40 MHz and 100 MHz radargrams near Biharigarh and Mujahidpur villages in Solani drainage basin (Uttarakhand and U.P.) and near Toka village in Markanda drainage basin (H.P.). [ABSTRACT FROM AUTHOR]

The purpose of this study is to analyze and characterize recent landslide events in the Larji-Kullu Tectonic Window (LKTW), and to establish a relationship between the tectonic and lithologic characters of the terrain and the landslides activity. Using multispectral satellite image analysis with selected field investigation, a landslide occurrence database has been generated for the period between 1984 and 2015. To decipher the accelerated occurrences of landslides in the region, an integrated study is undertaken in the Kullu (also known as Kulu) valley of Beas River basin within the LKTW complex, to analyze the litho-structural and terrain slope interactions using morpho-tectonic parameters such as Topographic/Bedding Plane Interaction Angle (TOBIA) index, terrain surface roughness index and lithological competency analysis. A prominent clustering of landslides is observed in the north of Sainj River, contained within the tectonic window. Major sites of landslides are found to be located in the intensely fractured Manikaran Quartzite occurring within the core of the LKTW. The landslides are mostly associated with southern and southwestern-facing slopes and activations are pronounced in the ‘Orthoclinal’ slope class with gradient of 37°-48°. Thematic maps, e.g., geological, structural, geomorphological, slope and slope-aspect maps are generated and considered together to understand the morpho-tectonic scenario of the tectonic window. Observations from the above-stated thematic maps along with the occurrences of moderate magnitude earthquake epicenters helped to infer neotectonic movements along the Sainj River fault. Tectonic upliftment of the northern bank of the Sainj River along with increased precipitation through decades has resulted in recurrent landslides within the LKTW. [ABSTRACT FROM AUTHOR]

Fluvial terraces are important geomorphic archive preserving information about past fluctuations in climate and tectonics. In tectonically active regions such as Himalayas which are also the drivers of Indian Summer Monsoon (ISM) and are also influenced by the past climatic changes. To understand the impact of two processes, different sections of fluvial terraces were studied along the Tista River in the Darjeeling Sikkim Himalayas over a stretch of ~65 km. An attempt has been made to reconstruct the geomorphic history of the region using Optically Stimulated Luminescence (OSL) dating and geochemistry. Four level of terraces were identified in the region as T4, T3, T2 and T1, in decreasing order of their ages. T3 terrace is nested into T4 and could only be differentiated on the basis of chronology. The upper age limit of T4 is ~72 ka and this period was followed by a glaciation phase. We do not get any deposits during this phase showing that this was a period of no active sedimentation. The T3 has an age range of ~ 50-30 ka and is regional in nature, whereas all other terraces are fragmentary in space. This time period was also an interglacial phase with similar precipitation conditions as of today. However, the Chemical Index of Alteration (CIA) values indicate that the chemical weathering was not intense during this period indicative of relatively dry condition. The T2 formed during ~ 24-11 ka which was period of Last Glacial Maxima (LGM) followed by interglacial period and Younger Dryas event. The striking difference between T4, T3 and T2, T1 is its terrace material. The T4 and T3 are composed of laminated sand with few intercalations of cobble-pebble layers whereas, the T2, T1 and present day channel are composed of pebble, cobble and boulder beds with few thin sand units. The river dynamics during formation of T4 and T3 was such that it could only transport sand sized particles while during formation of T2 and T1 it changed drastically. It is important to understand that this change was either induced due to climatic fluctuations or due to the tectonics. We observed in two of the studied sections the T 3 terrace was deformed indicating that this deformation event took place after its formation, i.e. 30 ka. This was followed by the formation of T2 terrace, pointing towards a tectonic activity between 30 ka and 24 ka which drastically changed the dynamics of the Tista River. Even the younger terraces viz. T2 and T1, also show warping indicating that the region is tectonically active in present day scenario, posing a serious problem for the local inhabitants. The climate and tectonics are working hand in hand in shaping the geomorphology of the region. [ABSTRACT FROM AUTHOR]

Geomorphic and morphotectonic evaluations of the Kashmir Basin have been carried by implicating different geomorphic indices such as stream-gradient index (SL), hypsometric integral (HI), drainage basin asymmetry (AF), valley floor height and width ratio (Vf), transverse topographic symmetry factor (T), mountain front sinuosity (Smf), drainage basin shape (BS) and sinuosity index (SI) for the categorization of relative index of active tectonics (RIAT) through the use of geographic information systems (GIS) so as to decipher the role of neotectonics in geomorphologic evolution of the basin. The verified RIAT classes through field investigation and validation reveal the traverse of twenty-one active faults in the basin with demarcation of three RIAT classes viz., class-1 (inactive 20.07% of the area), class-2 (moderately active; 36.52% of the area) and class-3 (very active; 43.4% of the area). The observed values of RIAT distribution pattern are well corroborated with field observations. Ultimately, the overall geomorphic outputs and clustering of recent seismicity support the active tectonic control over the Kashmir basin, India. [ABSTRACT FROM AUTHOR]

Structural and morphotectonic signatures in conjunction with the geomorphic indices are synthesised to trace the role of transverse tectonic features in shaping the landforms developed along the frontal part of the eastern Arunachal sub-Himalaya. Mountain front sinuosity ( S mf ) index values close to one are indicative of the active nature of the mountain front all along the eastern Arunachal Himalaya, which can be directly attributed to the regional uplift along the Himalayan Frontal Thrust (HFT). However, the mountain front is significantly sinusoidal around junctions between HFT/MBT (Main Boundary Thrust) and active transverse faults. The high values of stream length gradient ( SL ) and stream steepness ( K s ) indices together with field evidence of fault scarps, offset of terraces, and deflection of streams are markers of neotectonic uplift along the thrusts and transverse faults. This reactivation of transverse faults has given rise to extensional basins leading to widening of the river courses, providing favourable sites for deposition of recent sediments. Tectonic interactions of these transverse faults with the Himalayan longitudinal thrusts (MBT/HFT) have segmented the mountain front marked with varying sinuosity. The net result is that a variety of tectonic landforms recognized along the mountain front can be tracked to the complex interactions among the transverse and longitudinal tectonic elements. Some distinctive examples are: in the eastern extremity of NE Himalaya across the Dibang River valley, the NW-SE trending mountain front is attenuated by the active Mishmi Thrust that has thrust the Mishmi crystalline complex directly over the alluvium of the Brahmaputra plains. The junction of the folded HFT and Mishmi Thrust shows a zone of brecciated and pulverized rocks along which transverse axial planar fracture cleavages exhibit neotectonic activities in a transverse fault zone coinciding with the Dibang River course. Similarly, the transverse faults cut the mountain front along the Sesseri, Siluk, Siku, Siang, Mingo, Sileng, Dikari, and Simen rivers. At some such junctions, landforms associated with the active right-lateral strike-slip faults are superposed over the earlier landforms formed by transverse normal faults. In addition to linear transverse features, we see evidence that the fold-thrust belt of the frontal part of the Arunachal Himalaya has also been affected by the neotectonically active NW-SE trending major fold known as the Siang antiform that again is aligned transverse to the mountain front. The folding of the HFT and MBT along this antiform has reshaped the landscape developed between its two western and eastern limbs running N-S and NW-SE, respectively. The transverse faults are parallel to the already reported deep-seated transverse seismogenic strike-slip fault. Therefore, a single take home message is that any true manifestation of the neotectonics and seismic hazard assessment in the Himalayan region must take into account the role of transverse tectonics. [ABSTRACT FROM AUTHOR]

Tectonic process can influence the erosion and exert the first order impression on hydrographic network of an area. Geomorphometry, a mathematical analysis of the configuration of the landforms, allows quantifying the degree of landform evolution and is widely used as a measure of tectonic deformation/uplift. Alaknanda valley lies in the tectonically active Garhwal Himalaya which has experienced two disastrous large earthquakes in the last two decades. Morphometric analyses of the valley were carried out in a fluvial erosion dominated regime and the morphometric indices were derived from the ASTER (30 m × 30 m pixel) Digital Elevation Model (DEM) using Arc GIS. The results of the analyses reveal two zones of high deformation/uplift in the valley, viz., the zone of high deformation proximal to the Main Central Thrust (MCT) in the Inner Lesser Himalaya (ILH) and the second zone of moderate deformation/uplift in the Outer Lesser Himalaya (OLH), south of the Tons Thrust (TT). The high deformation in the ILH is ascribed to the focussed convergence and high precipitation; however, the causes for the moderate deformation in the OLH are yet to be established. [ABSTRACT FROM AUTHOR]

Seismic wave attenuation is one of the most important parameters that reflect characteristics of the medium traversed by the seismic waves. This parameter is essential for many studies such as determining earthquake source parameters, predicting earthquake strong ground motion, monitoring nuclear explosions and estimating seismic hazard. Since 1995, several region-specific attenuation relations have been developed for the Indian regions, but no such relation is available for the Bilaspur region of the Himachal Lesser Himalaya for the want of data. A six-station local seismological network, deployed in the environs of Koldam site, provided digital recordings of 41 local events occurred in the region from May 2013 to March 2014. This data set has been used to develop the attenuation relations for the region. Majority of the events occurred in the Himachal Lesser Himalaya between the main boundary thrust and the main central thrust. All events have epicentral distances <100 km and magnitudes between 0.5 and 2.9. Adopting the single backscattering model of Aki and Chouet (J Geophys Res 80:3322-3342, ), coda- Q ( Q) of the region has been estimated in lapse time windows of 20, 30 and 40 s, respectively. For 30-s lapse time window, the attenuation follows the relation Q ( f) = (70.3 ± 20.27) f for the region. The observed Q relation is compared with similar relations for seismically active Indian regions and some of the globally available relations. It is found that the average variation of Q for the Bilaspur region is very close to Amazon Craton (Brazil) due to similar lithologic setup. The variation of ' Q' and ' n' values indicates that the region is highly heterogeneous and seismically active. The region is more heterogeneous near the surface as compared to depth. The estimated Q relations can be utilized for computing source parameters of the local earthquakes and for seismic hazard assessment for the Bilaspur region of Himachal Lesser Himalaya. [ABSTRACT FROM AUTHOR]

Himalaya is an active fold and thrust belt formed due to continent-continent collision between the Eurasian and Indian plates. It comprises a 3000 km long chain of mountains that span ∼1000 km across, with major boundary thrusts viz., Main Central Thrust (MCT), Main Boundary Thrust (MBT) and the Main Frontal Thrust (MFT). MFT is marked as mountain front and is the most active thrust; however, evidence of tectonic activity along MCT and MBT also exists. Tectonic activity along MFT created uplifted terraces which now serve as geomorphic archives of past tectonic events. The present study focussed on a glacial-fed river Sankosh that originates in northern Bhutan, and crosses MCT, MBT and MFT before joining the Brahmaputra River in Assam. Due to tectonic uplift, the river shows a deflection at MFT, incising and thus forming four levels of strath terraces. Luminescence chronology, geomorphic studies and analysis of satellite images suggest four levels of terraces T4 (highest level, 195 m asl), T3, T2 and T1 (lowest level, 120 m asl). The quartz was found insensitive for luminescence dating, and thus fading corrected Infra-Red Stimulated Luminescence (IRSL) ages on feldspar minerals were measured that provided ages of 143-77 ka (T4), 65-36 ka (T2) and 35-14 ka (T1), respectively. The T3 terrace was present only on the right bank of the river and could not be accessed. These ages accord with other studies at the Chalsa and Malbazar, North Bengal (west of the study area) and this regional disposition of similar ages suggest that these formed during glacial-interglacial periods. The strath terraces indicate a time-averaged tectonic uplift with a 0.5 mm/year rate over the past 150 ka. [ABSTRACT FROM AUTHOR]

Uttarakhand Himalaya in India lies in the central seismic gap region identified by Khattri and Tyagi (Tectonophysics 96:281–297, 1983 ). Most of the area in Uttarakhand state has been placed under zone V (the highest seismic zone) and zone IV (second highest seismic zone) of the seismic hazard map published by Bureau of Indian standard, Govt. of India (BIS in Indian standards code of practice for earthquake resistant Design of Structures, Indian Standards Institution, New Delhi, 2002 ). Some of the thrust/faults in the region manifest evidence of neotectonics and recurrent seismicity (Valdiya and Pant in Indian Nat Sci Acad 112–117, 1986 ; Valdiya in Geodynamics of NW Himalaya Gondwana Research Group Memoir 1999 ; Thakur in Curr Sci 86(II):1544–1560, 2004 ; Paul et al. in Seismotectonic implications of data recorded by DTSN in the Kumaon region of Himalaya 2004 ). On the basis of strain accumulation, Bilham et al. (Science 293:1442–1444, 2001 ) suggested a future magnitude of M ≥ 8 in this region. Therefore, a great earthquake along main central thrust in the central seismic gap region has been modeled using semi-empirical technique of Joshi and Mohan (J Seismol 12:35–51, 2008 ). For modeling great earthquake, the shear wave quality factor $$ Q_{\beta } \left( f \right) = 30f^{1.45} $$ Q β ( f ) = 30 f 1.45 (Joshi et al. in J Earthq Technol 47(1):508, 2010 ) has been used for Pithoragarh region of Kumaon Himalaya. The strong-motion parameters [peak ground acceleration (PGA), spectral acceleration, and normalized spectral acceleration] are computed at five stations (Sobla, Didihat, Munsiari, Dharchula, and Pithoragarh) in Uttarakhand Himalaya. The maximum PGA of the order of “2 g” is computed due to scenario great earthquake in the region at Sobla station. Such type of study is quite helpful for seismic-resistant designs of the buildings in earthquake-prone areas and is essentially required in Uttarakhand Himalaya. [ABSTRACT FROM AUTHOR]

The geomorphology of the Deccan Volcanic Province (DVP) has its foundation in the eruption of flood basalts that covered nearly half of the Indian Peninsula during the Cretaceous – Paleogene transition and the asymmetric eastward tilt of the Peninsula. The northward trajectory of the Indian plate through the tropics leading to its collision with the Asian plate and the emergence of the Himalayan ranges are known to have resulted in significant climate changes through the Cenozoic. The DVP terrain preserves an imperfect, patchy record of these events and their impact on Cenozoic landscape evolution within an emergent continental block. The subhorizontal disposition of the stacks of lava flows in the DVP was interpreted to manifest the post-eruptive tectonic stability of this terrain. Earlier interpretations of the geomorphic characters of this terrain, with its step-like slope-profiles were consequently attributed to dominant climatic control. We review the regional topographic framework with additional inputs from the structural framework of the Deccan flood basalts, characters of the major rivers draining the province largely based on their high scale longitudinal profiles and Quaternary hinterland sedimentary basins within the DVP. It is evident that the erstwhile interpretation of the DVP as a singular morphotectonic unit where the antecedent drainage responded to Cenozoic tropical climate change with subsidiary tectonic controls requires re-examination. The component blocks of the DVP have differing morphotectonic characters because of the subtle diversity in their relative uplift / sag trajectories and structural characters. The influence of the monsoon climate (with alternating stronger and weaker phases) on landscape evolution in the subprovinces of the DVP is likely to be less significant than was earlier believed. The Deccan landscape reflects the Cenozoic reactivation of ancient tectonic zones that bound the constituent blocks of the province. Its landscape is carved by an antecedent tropical drainage, that was modified by Paleogene and Neogene intracontinental block movements driven by far-field stresses derived from the ridge-push of the Indian Ocean in the south and slab-pull of the subducting Indian Plate in the north. The Deccan landscape provides an example of how lithological and climatic controls on drainage evolution are overprinted by weak midcontinental tectonics. [ABSTRACT FROM AUTHOR]

Assessment and inventory of landslide susceptibility are essential for the formulation of successful disaster mitigation plans. The objective of this study was to assess landslide susceptibility in relation to geo-diversity and its hydrological response in the Lesser Himalaya with a case study using Geographic Information System (GIS) technology. The Dabka watershed, which constitutes a part of the Kosi Basin in the Lesser Himalaya, India, in the district of Nainital, has been selected for the case illustration. The study constitutes three GIS modules: geo-diversity informatics, hydro informatics and landslide informatics. Through the integration and superimposing of spatial data and attribute data of all three GIS modules, Landslide Susceptibility Index (LSI) has been prepared to identify the level of susceptibility for landslide hazards. This resonance study, carried out over a period of five years (2007–2011), found that areas of most stressed geo-diversity (comprising very steep slopes above 30°, geology of Lower Krol and Lariakanta formation, geomorphology of moist areas and debris sites, land use of barren land with a very high drainage frequency and spring density) have a high landslide susceptibility because of high rate of average runoff (33 l/s/km2), flood magnitude (307.28 l/s/km2), erosion (398 tons/km2) and landslide density (5–10 landslides/km2). The areas of least stressed geo-diversity (comprising gentle slopes below 10°, geology of Kailakhan and Siwalik formation, geomorphology of depositional terraces, land use of dense forest with low drainage frequency and spring density) have the lowest landslide susceptibility because of the low rate of average runoff (6.27 l/s/km2), flood magnitude (20.49 l/s/km2), erosion (65.80 tons/km2) and landslide density (1–2 landslides/km2). [ABSTRACT FROM AUTHOR]

From the end of the Eocene through the Pliocene, the Alpine-Himalayan Belt underwent collisional shortening induced by convergence of the Gondwana plates with the Eurasian Plate and varied in orientation from the north-northwestern to the northeastern directions. The collisional shortening was expressed in folding, thrusting of continental crustal tectonic sheets over one another, and closure of the residual basins of Neotethys and its backarc seas; it resulted in local thickening of the crust and its isostatic uplifting. As a rule, the uplifts were not higher than ∼1.5 km. In other words, before the Pliocene, the growth of local mountain edifices was caused by collisional shortening of the belt. Isostatic uplifting of the thickened crust was continued in the Pliocene and Quaternary even more intensely than before, but the general rise of the mountain systems was superposed on this process. The rise substantially exceeded in amplitude the contribution of the uplift caused by shortening and did not depend on the preceding Cenozoic history of either territory. Not only the mountain ridges but also most adjacent basins were involved in rising, which eventually led to the contemporary mountain topography of the belt. The spread of the hot and fluidenriched asthenosphere of the closed Tethys beneath the orogenic belt could have been a cause of such additional rising. The uplift was an isostatic reaction to decompaction of the lithospheric mantle partly replaced with asthenosphere and of the lower crust subject to retrograde metamorphism under the effect of cooled asthenospheric fluids. The deep transformations are also probably responsible for deepening of some basins in the Pliocene-Quaternary and more contrasting transverse segmentation of the belt. [ABSTRACT FROM AUTHOR]

Neotectonics play an important role in the formation of lakes, especially near active suture zones. The best suited areas where such changes are observed are the tectonically active mountainous regions of Himalaya. However, in an inaccessible terrain like Higher-Himalaya, active tectonic studies related to development of newer and reactivated faults are less conceived. In this article, an attempt has been made to identify active faults and Neotectonic activity in the Tso Morari area in Ladakh, North-West Himalaya, with the help of remote sensing and digital elevation model (DEM) techniques. The results suggest that Tso Morari Lake is developed due to Neotectonic uplift in the region which created a fault scarp in E–W direction. The horizon blocking technique with the aid of elevation, slope and aspect map is used to demarcate the E–W trending younger fault. Moreover, the earthquakes foci also lie along this E–W direction which has restricted the seismic activity to its southern part. [ABSTRACT FROM PUBLISHER]

To study neotectonics, the structural and morphotectonic aspects are studied along a part of mountain front region of Northeast Himalaya, Arunachal Pradesh, India. Unpaired river terraces are recognized near north of transverse Burai River exit, which is cut by an oblique fault. Across this fault, fluvial terraces are located at heights of 22.7 and 3 m, respectively, on the left and right banks. A water gap is formed along the river channel where the uplifted Middle Siwalik sandstone beds dipping 43° towards ENE direction, thrust over the Quaternary deposit consisting of boulders, cobbles, pebbles and sandy matrix. This river channel incised the bedrock across the intraformational Ramghat Thrust along which the rocks of the Middle Siwalik Formation thrust over the Upper Siwalik Formation. Recent reactivated fault activity is suggested north of the Himalayan Frontal Thrust that forms the youngest deforming front of the Himalaya. The uplifting along the stream channel is noticed extended for a distance of ~130 m and as a result the alluvial river channel became a bedrock river. The relative displacement of rocks is variable along the length of strike-slip faults developed later within the Ramghat Thrust zone. Longitudinal and Channel gradient profiles of Burai River exhibit knick points and increase in river gradient along the tapering ends of the profiles. The study suggests active out-of-sequence neotectonically active thrusting along the mountain front. Neotectonics combined with climatic factor during the Holocene times presents a virgin landscape environment for studying tectonic geomorphology. [ABSTRACT FROM AUTHOR]

Abstract: While the right-slip Karakorum fault is one of the most prominent structures in the Himalayan–Tibetan orogen, its evolution and role in accommodating deformation related to the collision between India and Asia is controversial. Different models interpret the Karakorum fault as either: 1) a long-lived, stable feature analogous to a plate boundary structure, or 2) an evolving fault system with limited displacement (<200km) and transient kinematics. While active deformation along the southern segment of the Karakorum fault is well established, neotectonic activity along the fault north of its intersection with the active left-slip Longmu–Co Gozha–Co fault system has not been documented. Analysis of Corona and ASTER satellite images along the northern end of the Karakorum fault zone provide several lines of evidence that show this portion is no longer active: 1) multiple generations of Quaternary glacial and fluvial deposits which can be correlated with previously dated deposits in the region, the oldest of which are >150ka, overly the trace of the two strands of the Karakorum fault and show no evidence of tectonic disturbance; 2) older (late Pliocene to early Quaternary) loess deposits which overlie the trace of the fault are either undisturbed, or are cut by small normal fault scarps with no evidence of strike-slip displacement; 3) east–west trending bedrock incised stream valleys up to 500m deep cross both strands of the fault with no sign of lateral deflection. I suggest that termination of slip along the northern segment of the Karakorum fault occurred in the Pliocene due to southward propagation of the Altyn Tagh fault system along the Longmu–Co Gozha Co fault and impingement of the Karakorum fault. This study suggests that large intracontinental strike-slip faults embedded within orogenic plateaus are transient features which should be expected to have complicated kinematic histories and short life-spans relative to the life of an orogenic belt. [Copyright &y& Elsevier]

Abstract: The paper describes Late Quaternary pedosedimentary sequences of the alluvial fans from the Kangra basin of NW Himalayas for tectonic and paleoclimatic implications. In the proximal part of the Kangra basin three coalescing alluvial fans, namely Rait-Rihlu fans (~65 km2), Kangra fans (~200 km2), and Palampur fans (~170 km2) from west to east evolved due to reactivation of longitudinal and transverse faults and climatic changes during the Late Quaternary. The fans are characterised by subsidence of Rait-Rihlu fans, uplift of Kangra fans and tilting of Palampur fans. The thick (~90 m) pedosedimentary sequences exposed along the rivers characterise the dominant formative processes over the fans. The stream flow sediments dominate the Rait-Rihlu fans, whereas the debris flow sediments dominate the Kangra and Palampur fans. The fan sequences are also marked by the formation of strongly developed paleosols on loess (L1–L3 loess paleosols) and weakly developed paleosols on fluvial deposits in response to the tectonics and climate change in NW Himalayas. Formation of the loess in proximal and distal settings of the alluvial fans is related to the cool–dry climates during the advance of glaciers in the adjoining areas at 78 ka, 44 ka, 30 ka and 20 ka when climate was approaching towards the last glacial maxima. Field characters, micromorphology, grain size and clay minerals of these loessic deposits suggest strong pedogenesis of the loess during a warm–humid climate after the retreat of glaciers in the NW Himalayan region and are likely related to marine isotope stages (MIS4/5 in proximal and MIS2/3 in distal). The loess-paleosols show some degree of syndepositional pedogenesis in upper horizons and are accretionary in nature. Weakly expressed pedogenic features in fluvial and debris flow deposits suggest rapid sedimentation over unstable surfaces related to the reactivation of Main Boundary Thrust (MBT) and other regional faults. [Copyright &y& Elsevier]

Abstract: The Himalayan orogenic belt, formed as a result of collision tectonic processes, shows abundant evidence of neotectonic activity, active tectonics, and the occurrence of historical earthquakes. Its frontal deformation zone is characterized, in some segments, by intermontane longitudinal valleys (duns). Such frontal segments of the Himalaya are marked by the occurrence of multiple mountain fronts. In one such segment of the foothills of the NW Himalaya, the Pinjaur dun is developed and marked by three mountain fronts: MF1A and MF1B associated with the southernmost Himalayan Frontal Thrust (HFT), MF2 associated with the Sirsa fault, and MF3 associated with the Barsar thrust along the southern margin of the relatively higher main part of the sub-Himalaya. Geomorphic responses to the tectonic activity of these and related structural features have been analyzed through the use of geomorphic indices, drainage density, stream longitudinal profiles, drainage anomalies, and hypsometric analysis. Also, fault and fold growth and their expression on landform development was studied using a combination of surface profiles and field observations. The values of valley floor width to height ratio (V f) for valleys associated with MF1 ranged between 0.07 and 0.74, and for valleys associated with MF2 ranged from 1.02–5.12. V f for the four major valleys associated with MF1B ranged from 1.1–1.7. The asymmetry factor for 26 drainage basins related to MF1A indicate these have developed under the influence of a transverse structure. These results taken together with those obtained from the Hack profiles and SL index values, hypsometry, drainage density, and drainage anomalies suggest that the faults associated with the mountain fronts and related structures are active. Active tectonics and neotectonic activity have led to the formation of four surfaces in the Pinjaur dun. In addition, an important drainage divide separating the Sirsa and Jhajara drainage networks also developed in the intermontane valley. Surface profile analysis helped in deciphering the growth history of the fault bend fold structures of the outermost Siwalik hills. The effects of tectonic activity on the proximal part of the Indo-Gangetic plains are interpreted from the remarkable river deflections that are aligned linearly over tens of kilometers in a zone about 10 km south of the HFT. Based on these integrated structural and tectonic geomorphological approaches, a morphotectonic evolutionary model of the dun has been proposed. This model highlights the role of uplift and growth history of the fault bend fold structures of the outermost Siwalik hills on (i) the depositional landforms and drainage development of the Pinjaur dun, and (ii) valley development of the outermost Siwalik hills. Importantly, this study postulates the formation of an incipient mountain front that is evolving ahead of the HFT and the outermost Siwalik hills in the Indo-Gangetic plains. [Copyright &y& Elsevier]

Manifestation of ongoing active tectonics in the Himalayan foothill region is evident from a number of major M > 7.5 and great earthquakes (M ≅ 8) which occurred within the last century or so, besides the recurrent seismic events of moderate magnitude. Active faults of the Himalaya are significant in the study of active tectonics because displacements along them reflect the continued tectonic movements. The present study deals with morpho-structural analysis using remotely sensed data along with selected field investigations in delineating new traces of active faults in the Pinjaur Dun of the northwestern Frontal Himalaya. Fault scarps with heights varying from 5 to 25 m observed along the faults are indicative of long term uplift/deformation in the current tectonic regime and cumulative slip along them. These active faults are signatures of Quaternary tectonics in the zone between the Main Boundary Thrust (MBT) and the Himalayan Frontal Thrust. [ABSTRACT FROM AUTHOR]

In an orogenic belt like the Himalaya, expressions of neotectonic activities are numerous, manifested mainly by faulting and tilting of Quaternary deposits (alluvial fans and river terraces), fault controlled channels, river capture, etc., well‐expressed on satellite images. Studies on quantification of block tilting of river basins in the Himalaya have not been attempted so far. The aim of the present communication, therefore, is to quantify block tilting using morphotectonic parameters, such as basin asymmetry factor (AF) and transverse topographic symmetry factor (TF) in the uppermost courses of the Markanda and Bata rivers (Himachal Pradesh). The AF values of 89.34 and 25.69 and the TF values of 0.77 and 0.67 due south‐southwest respectively for Markanda and Bata indicate that the northern segments of the Markanda and Bata river catchments are tilted south with respect to the trunk streams. Fault and lineament controlled channels of the Bata and Markanda rivers and some of their tributaries further corroborate the neotectonic activities in this region. [ABSTRACT FROM AUTHOR]

Two end‐member kinematic models of crustal shortening across the Himalaya are still debated: one assumes localized thrusting along a single major thrust fault, the Main Himalayan Thrust (MHT) with non-uniform underplating due to duplexing, and the second one advocates for out‐of‐sequence thrusting in addition to thrusting along the MHT and under-plating. Furthermore, several studies argue that all crustal shorting during the Quaternary is accommodated within Sub-Himalayan fold and thrust belt. In this study, we combined tectonogeomorphic field observations, topographic analysis and luminescence dating of the Quaternary alluvium from the Kishtwar region in NW Himalaya. We have used 30m SRTM data to analyze the regional geomorphic parameters of the area and found that the river Chenab shows, as previously reported, significant changes in the longitudinal river profile, hypsometric integral, valley width and normalized steepness indices across the Kishtwar window situated ~ 150 km inside the Himalayan front. Unadjusted hypsometry, high ksn values, and several non-lithological knickpoint zones in the Chenab river profile hints towards possible ongoing neotectonic activity especially at the western margin of the window. We combined our morphometric analysis with field observation and field data on rock strength and observed tilted Quaternary deposits along the Chenab valley. We have observed faults disrupting Quaternary fluvial sequences and ~20֯ NE-tilted fluvial sequence of pebble conglomerate and coarse sand layers in the vicinity the town of Kishtwar. Even, the observed knickpoints within the window do not correspond to significant changes in the substrate rock strength and therefore hint about their non-lithologic origin. We also observed changes in the drainage pattern of Chenab, as it was frequented by large landslides (despite being located in a fairly-low rainfall region) and landslide-dammed lakes throughout the Kishtwar window and downstream. Previously published young (<3 Ma) apatite fission track ages from the Lesser Himalayan duplex in the Kishtwar Window suggest higher exhumation over million-year timescale. Therefore, our findings possibly hint towards a protracted tectonic uplift process – and the quaternary tilted deposits suggests that this deformation is active until today or very recent. Moreover, frequent low-magnitude mid-crustal (8-30 km) seismic events, steep channel gradients, high angle bedrock foliations of the Lesser Himalayan duplex, multiple knickpoints and young AFT ages within the Kishtwar window hints about active shortening accommodated due to movement along a mid-crustal ramp of the MHT.We are processing the OSL samples obtained from the deformed sand and silt layers within the alluvium. We are hopeful that we will be able to chronologically constrain the late Quaternary deformation with the new luminescence ages. [ABSTRACT FROM AUTHOR]