The Himalayan frontal thrust marks the southern boundary of the deformation front of the Himalayan orogenic belt [1]. The thrust faulting in the frontal Himalayan terrain is strongly influenced by the spatial and temporal patterns of active deformation recorded on the margin of the orogenic belts. The accumulated strain on account of the continuous northward migration of the Indian plate finds frequent release in the form of seismic events that display a conspicuous inter-relationship amongst the basal decollement surface, rate of thrusting and plate motion rates [2] [3] [4]. The data emerging from the spectacular surface rupturing earthquakes suggest that the current tectonic activity is primarily occurring in the frontal thrust terrain [5]. Active tectonic morphometric studies within the orogenic belts are of significant importance in the context of evaluating the models of deformation, thrust belt kinematics, as also the seismic hazard faced by the population habiting in close proximity to the active faults. [6] discussed the neotectonic activities that have occurred in the Himalayan terrain. [7] described the structure and shortening of the Kangra and Dehra Dun re-entrants of Sub-Himalaya. [8] has done reassessment of earthquake hazard based on a fault-bend fold model of the Himalayan plate. [9] has described the palaeo-seismicity and seismic hazard assessment in the Himalaya. [10] has identified and described the uplift and convergence along the Himalayan Frontal thrust of India. [11] has identified and described neo-tectonic activity near Nada village and Morni Hills in the Himalayan foothills. [12] described the earthquake recurrence and rupture dynamics of Himalayan Frontal Thrust. [13] discussed the convergence across the northwestern Himalaya. [14] discussed reactivation of Himalayan frontal fault system and its implications. [15] described the shutter ridges and sag ponds along the Jainti Devi Fault near Chandigarh. [16] [17] described the neotectonic and seismo-tectonic characterization of the frontal Himalayan terrain. [18] documented recent fold growth and drainage development in the Janauri and Chandigarh anticlines of the Siwalik foothills. The neotectonic activity in the Markanda and Bata River Basins in Himachal Pradesh has been investigated by [19] and their study suggested upliftment and tilting of the Markanda and Bata River Basins due south. Seismites occurring in the frontal Himalayan terrain near Panchkula in Haryana were identified by [20]. [21] assessed the tectonic character of the terrain in the Frontal Siwalik hills near Trilokpur, northwestern Himalaya using remote sensing and tectonic morphometric approach. A comprehensive evaluation of the tectonic morphometric indices in terrain characterization has been attempted by [22]. Besides [23] [24] [25] [26] [27] have also worked on active tectonic aspects in the frontal Himalayan terrain of the northwestern Himalaya. The present study is aimed at identifying the active tectonic elements in the Kashmir Himalaya, especially in the region between the Basantar and the Ravi Rivers, as the Kashmir Himalaya has been considered to represent a seismic gap due to non-availability of historical earthquakes in this region [28] [29] except Kangra earthquake in 1905 and Uri-Muzzafrabad earthquake in 2005.

The Middle Miocene to Middle Pleistocene (23.5 m.a. to 1.6 m.a.) Siwalik group of rocks are quite well represented in the foothills of the Jammu and Kashmir Himalaya especially in the vicinity of Ravi River. The frontal Siwalik terrain between the Ravi and the Basantar River comprise the Upper Murree formation, the Lower Siwalik subgroup (Mansar Formation), the Middle Siwalik subgroup (Dewal and Mohargarh formations), and the Upper Siwalik subgroup (Uttarbahni and Dughor formations) as given (Figure 1) by [30] [31] (Table 1).

The rocks of the Siwalik group in study area occur as an asymmetrical anticline referred to as the Surin-Masatgarh anticline. The rocks exhibit N50˚W - S50˚E trend with the dominant SW dip direction. The Surin-Masatgarh anticline marks the thrust front [34]. The folding of this anticline has been estimated on the basis of palaeomagnetic data and thermo chronometry. Detritial apatite studies by [35] suggests onset of folding before 2 m.a., while the palaeomagnetic data by [31] [36] suggests an age between 1.6 to 2.1 m.a.

The southern limb of the asymmetrical Surin-Masatgarh anticline between the Ravi River and the Basantar River is 60 km in length and 20 km wide at Basantar re-entrant and 10 to 12 km wide at Ravi re-entrant. The major geomorphic features identified on the satellite imagery include the Siwalik Hills, alluvial fans, piedmont fan deposits, alluvial plains and River terraces. Low, middle and high hills represent the Upper, Middle and Lower Siwaliks with in between intermontane basins (duns). The Siwalik Hills extend in a NW-SE direction in the form of a linear sinuous asymmetrical anticlinal ridge. The Lower Siwalik Mansar Formation (Lower Miocene to Middle Miocene) comprise well indurated fine to medium grained pale grey to dark grey coloured sandstones, siltstones and mudstones. The Middle Siwalik Dewal Formation (Early Pliocene) and Mohargarh Formation (Middle Pliocene) comprise massive, medium to poorly indurated, pale grey to light brown coloured sandstones, siltstones and mudstone. The upper Siwalik Parmandal formation (Late Pliocene) comprises light brown to dark grey sandstone and mudstone with minor intercalations of pebbly beds that grades into sandstone and conglomerate in Nagrota fm. The Nagrota formation (Early Pleistocene) is represented by light to dark grey to pale brown sandstone and mudstone in the lower part and coarser clastics in the upper part. The upper Siwalik Dughor formation (Middle Pleistocene) represent the Boulder Conglomerate unit and is represented by matrix supported polymictic friable conglomerate containing sandstone lenses and thin beds of friable sandstone and mudstone. Alluvial fans comprise a chaotic intermix of cobbles, pebbles, granules, sand, silt and clay particles which at places are intermixed with calcareous concretions. The piedmont plains are made up of poorly sorted debris, assorted sediments debouched by streams, draining the region. The terrain between the Ravi River and the Basantar River is being closely examined to identify active tectonic features in the terrain. Development of shutter ridges is observed along all the streams through which the linear tectonic element crosses on the basis of movement seen along this element, which is being named as Goran fault. The fault is active and trends northwest-southeastwards. This fault is a sinistral strike slip fault with considerable oblique slip component. The fault has a surface expression of about 100 km and a significant portion of it appears to be hidden.

Fault scarps are observed in the Ujh River near Jakhole village in the Kathua district of Jammu and Kashmir (Figure 2(a)). Triangular facets along the Goran fault are observed along the Ravi River near Basantpur-Jugial region (Figure 2(b)). Shutter ridges of 2000 m length are developed along all Rivers and major streams (Figure 2(c)). Development of sag pond is observed along the Ujh River (Figure 2(d)). Unpaired terraces have been identified in the vicinity of Ravi River near Basantpur-Jugial region (Figure 3). During field work in the Jugial

region six terraces (T1, T2, T3, T4, T5 & T6) have been identified on the left bank of the Ravi River while only strath terraces (T1 & T2) have been identified on the right bank of the Ravi River. The terraces are made up of unconsolidated pebbles, sand, silt and clay. The younger terraces namely T5 and T6 are more fragile as compared to the older terraces.

The active tectonic characterization of the terrain in the vicinity of Ravi River in the frontal Siwalik terrain is carried out in a multidisciplinary manner. The data obtained from comprehensive field surveys, satellite imageries and morphometric investigations is being analyzed to ascertain the tectonics of the area of investigation. The Google Earth images (Figure 4) and LISS-III imageries (Figure 5) are being analyzed for visual identification and interpretation of geologic and geomorphic features.

Active tectonic geomorphic indices viz. stream length gradient index by [37], stream sinuosity index [38], mountain front sinuosity index, ratio of valley floor to valley height [39] [40] hypsometric integral, asymmetry factor and basin elongation ratio have been computed for the affected portion of the terrain in the region. The features identified and interpreted on the imageries and the data generated through ArcGIS have been physically verified in the field through comprehensive field investigations. The Digital Elevation Model (DEM) of the selected terrain has been prepared and the LISS-III false colour composite imagery has been draped over it to understand the tectonic character of the region.

Morphotectonic analysis is widely used as a basic reconnaissance tool for geomorphic evaluation of active tectonics. The morphotectonic indices computed to substantiate the role of active tectonics in research area have been briefly discussed below. The channel morphology, the fluvial processes and the hydrological characteristics of a River are significantly influenced by the tectonic deformation processes. During the course of study significant water channels, namely the Ravi, the Ujh the Basantar with their tributaries namely the Sahaar stream and the Tarnah stream have been examined in detail to identify the signatures of presence of active tectonic control in the area of the investigation.

Morphometric analysis of the streams was carried out on the basis of lineament analysis and anomalous stream offsets. The vector layer for lineament was digitized. The linear element has resulted in stream offsets along all the streams that cross its surface trace. The stream offset (L1) for the Basantar River is 2000 m, stream offset (L2) for the Tarnah stream is 2000 m, stream offset (L3) for the Ujh River is 2000 m, stream offset (L4) for the Sahaar stream is 2000 m and stream offset (L5) for the Ravi River is 2000 m (Figure 4). The tectonic morphometric analysis for stream offsets L1 to L5 is being carried out and the tectonomorphometric indices namely stream length gradient index (SL), stream sinuosity index (S), mountain front sinuosity index (S_mf), basin asymmetry ratio (AF), basin elongation ratio (Eb), valley floor width to valley height ratio (V_f) and hypsometric integral (Hi) for all the River segments viz. Basantar (1), Tarnah (2), Ujh (3), Sahaar (4) and Ravi (5) have been computed.

The Samba and the Kathua ditricts of Jammu and Kashmir are densely populated. Majority of the rural folk live in the non-masonary structures. Majority of such structures are built on the hill slopes and are vulnerable to seismic shaking. The Kangra earthquake (1905) and the Uri-Muzzfrabad earthquake (2005) caused considerable damage to life and property in this region. Identification of active faults is a significant parameter in assessing the seismotectonics of a region. It is in this context that the region between the Basantar and the Ravi Rivers is being closely examined to identify active faults on the basis of tectonic morphometric indices and field studies. The values of the various indices viz. stream sinuosity (S), stream length gradient index (SL), valley floor width to valley height ratio (V_f), mountain front sinuosity index (S_mf), hypsometry index (Hi), drainage basin asymmetry factor (AF) and basin elongation ratio (Eb) reveal active tectonic character of the terrain.

The terrain between the Basantar River and the Ravi River has been closely examined. The tectonic morphometric indices along the Ravi River, the Sahaar stream, the Ujh River, the Tarnah stream and the Basantar River are indicative of active tectonic setup of the terrain. The field observations in conjunction with remote sensing investigations of the study area reveal the presence of an active sinistral strike slip fault which is named as Goran Fault. This fault has a surface expression of around 100 km and it is a significant seismo-tectonic element which needs to be taken into account considering the seismically active nature of the frontal Himalayan terrain of the Kashmir Himalaya. Future studies should consider a comprehensive subsurface investigation by appropriate geophysical techniques to identify and characterize the tectonic setup of the populated Himalayan foothills.

The research work was carried out in Department of Geology, Kurukshetra University, Kurukshetra. The authors are thankful to scholars of the sedimentology group namely Dr. Rajesh Ranga, Messers Yoginder Singh and Subhash for their assistance in field and laboratory investigations.

The authors declare no conflicts of interest regarding the publication of this paper.

Sharma, V. and Chaudhri, A.R. (2020) Active Tectonic Strike-Slip Fault Development near Goran, Samba and Kathua Districts, Jammu and Kashmir. Open Journal of Geology, 10, 301-316. https://doi.org/10.4236/ojg.2020.104016