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Regional tectonic map of the westernmost part of the frontal Himalaya. Solid black lines are major tectonic lines from Burg et al. (2005). Red lines show active faults from Nakata et al. (1991) and Avouac et al. (2006). The 2005 surface rupture is denoted by aligned red circles. Affected area of the 1555 earthquake (Ambraseys and Jackson, 2003) and the IKSZ (zone of high microseismicity; Armbruster et al., 1978; Seeber and Armbruster, 1979) are also shown by blue dashed ellipses.
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To provide a detailed record of a relatively rare thrust surface rupture and examine its active tectonic implications, we have conducted field mapping of the surface rupture associated with the 2005 M-w 7.6 Kashmir earthquake. Despite the difficulty arising from massive earthquake-induced landslides along the surface rupture, we found that typical...
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... These areas are from south to north: The Salt Range, the Potwar and Kohat plateaus, the Hill Ranges, the intermontane basins, the southern Kohistan Ranges, the Nanga-Parbat-Haramosh regions, the Main Mantle Thrust, and the Kohistan island arc, which is separated from Asian rocks of the Pamirs to the north by the Main Karakorum Thrust. Seismically north Pakistan is very active and the faults within fold-and-thrust belt have been frequently producing moderate to large seismic events that include the Kashmir earthquake of 2005 that resulted in more than 75000 lives loss in addition to a colossal economic loss [44][45][46][74][75][76][77][78][79]. ...
The overall seismicity of Pakistan from 1820 to 2020 is analysed in terms of its multifractal behaviour. Seismic events of magnitude ML=3.0 and above are spatially clustered into four distinct groups, each one corresponding to a different region of high seismic activity. The Multifractal Detrended Fluctuation Analysis (MFDA) method applied on each cluster reveals pronounced inter-cluster heterogeneity in terms of the resulting generalised Hurst exponent and fractality spectrum, possibly due to the particular tectonic characteristics of the regions under investigation. Additional results on the variability of the Gutenberg-Richter b-value across the defined clusters further corroborate the uniqueness of the seismic profile of each region.
... Using a database of nine reverse faulting earthquakes from Wesnousky [54] and Kaneda et al. [55], Moss and Ross [22] have developed the required probability functions for reverse type of faulting, which can be considered suitable for the thrust type of faulting for the fault plane associated with the MBT in the present study. They have shown that the normalized average displacement, z = D∕AD , can be described by the gamma density function with the shape parameter a and the scale parameter b given by In these expressions, x∕L is the ratio of the distance x of the site of interest from the nearer end of the fault rupture length to the total fault rupture length L , such that x∕L lies between 0 and 0.5 only. ...
To ensure the seismic safety of important buildings and infrastructure facilities in seismically active areas, it is necessary that, in addition to the various ground motion parameters, the seismic hazard is also characterized in terms of many other destructive natural effects of earthquakes like soil liquefaction and permanent fault displacement for example. The probabilistic seismic hazard analysis methodology can in principle be applied to quantify any of the destructive effects of the earthquakes in a region, provided a formulation has been developed to compute the probability with which a specified level of that effect can be exceeded at a site of interest due to given earthquake magnitude and location. Several investigators have developed necessary relationships and methodologies to estimate this probability for the permanent fault displacement, which may be a potential and primary cause of damage to long structures like bridges, tunnels, pipelines, dams and buried structures, if an active fault happens to cross or pass by such a structure. Based on a comprehensive literature survey and critical analysis of the results obtained for various possible alternatives, we have finalized a methodology for probabilistic fault displacement hazard analysis suitable for a 257 km long strand of the main boundary thrust (MBT) in the Garhwal-Kumaon Himalaya. Formulations are proposed for estimation of both the on-fault principal displacement and the off-fault distributed displacement, which can also be applied to any other thrust fault in any other segment of the Himalaya. The application of the proposed methodology to obtain the on-fault displacement estimates for a site at the midpoint of the selected strand of the MBT is found to provide physically realistic displacement values for very long return periods of upto 100,000 years. The off-fault displacements are found to decrease very fast with distance from the site on MBT and become practically insignificant at a distance of only two km.
... These areas are from south to north: The Salt Range, the Potwar and Kohat plateaus, the Hill Ranges, the intermontane basins, the southern Kohistan Ranges, the Nanga-Parbat-Haramosh regions, the Main Mantle Thrust, and the Kohistan island arc, which is separated from Asian rocks of the Pamirs to the north by the Main Karakorum Thrust. Seismically north Pakistan is very active and the faults within fold-and-thrust belt have been frequently producing moderate to large seismic events that include the = 7.6 Kashmir earthquake of 2005 that resulted in more than 75000 lives loss in addition to a colossal economic loss [44][45][46][74][75][76][77][78][79]. ...
The overall seismicity of Pakistan from 24 B.C to 2020 is analysed in terms of its multifractal behaviour. Seismic events of magnitude ML=3.0 and above are spatially clustered into four distinct groups, each one corresponding to a different region of high seismic activity. The Multifractal Detrended Fluctuation Analysis (MFDA) method applied on each cluster reveals pronounced inter-cluster heterogeneity in terms of the resulting generalised Hurst exponent and fractality spectrum, possibly due to the particular tectonic characteristics of the regions under investigation. Additional results on the variability of the Gutenberg–Richter b‐value across the defined clusters further corroborate the uniqueness of the seismic profile of each region.
... The earthquake distribution suggests a dominance of reverse and strike-slip events in the eastern portion of Borneo. Tapponnier and Molnar, 1977;Avouac et al., 2006;Pathier et al., 2006;Kaneda et al., 2008;Kothyari et al., 2010;Whittaker and Boulton, 2012;Boulton and Stokes, 2018;Kothyari et al., 2019;Bradley et al., 2019;Shah et al., 2020;Shah et al., 2022;Luirei et al., 2021;Sahari et al., 2023;Kothyari et al., 2022Kothyari et al., , 2023. Satellite-imagery-based analysis has proved highly advantageous in inaccessible regions for multiple reasons, such as forest cover, terrain complexity, political problems and so on (Cullen, 2010;Shah et al., 2018;Shah et al., 2020;Johnson and Cullen, 2022). ...
... This interpretation, however, requires validation through geodetic inversion. Such peaks usually define the location of the ruptured asperity (Kaneda et al., 2008) where the highest stress drop occurs due to peak moment release from the accumulated potential energy (Freymueller et al., 1994). ...
... Topography and bedrock geology may also control the rupture (Kaneda et al., 2008), such that the southwestern rupture termination in the study is on an alluvial plain, succeeded by rugged topography northwards. The narrow stepover in Palanas ...
Optical correlation, interferometry, and field investigation of laterally offset features were undertaken to analyze the kinematics of the 2020 Mw6.6 Masbate earthquake. Coseismic displacement fields from optical correlation show a maximum displacement of 0.61 m corresponding to Mw6.64 geodetic moment magnitude and a lone asperity in Cataingan. Post-seismic deformation from interferometry highlights a maximum 0.14 m sinistral displacement equivalent to a Mw6.15 post-seismic moment magnitude, with coincident afterslip and coseismic slip distributions. The measured slip decreased towards the north, suggesting the presence of a slip barrier where stress can accumulate. Slip measurements and rupture length estimates characterize the Masbate segment as capable of producing unusually long ruptures with significant offsets despite the presence of creep. Post-seismic interferograms resolved the rupture far better than optical correlation, which was degraded due to high amplitude noise from sensor and environmental sources. Nevertheless, the resultant surface rupture morphology, as observed in optical correlation outputs and interferograms, demonstrated the presence of two transtensional basins in the north and south of the province, interlinked by a stepover of the respective Riedel shear zones. This review of the 2020 Mw6.6 Masbate earthquake reveals new insights into the seismic hazard and seismotectonic setting of Masbate province in Central Philippines.
... It suggests that major/great earthquake rupture on the MHT typically spreads to the surface up to the MFT. In some instances, the rupture propagates to the surface within the wedge through out-of-sequence thrusting and these thrusts that are out-of-sequence are generally splays to the MHT, e.g., the 2005 Kashmir earthquake (Kaneda et al., 2008). In few cases, it remains confined on the MHT without reaching the surface along the MFT or along any other fault within the wedge and thus remaining blind, e.g., the 2015 Gorkha earthquake (Elliott et al., 2016;Li et al., 2018). ...
GNSS measurements based geodetic studies have led to researchers explaining the regional deformation in the Himalaya in terms of arc-parallel shearing and arc-normal compression (Fig 1 - Refer Text). Arc-Parallel extension is caused due to an increase in the shearing rate, which is reflected in the increasing arc-parallel velocities, as one moves along the arc away from the arc-center. This has prompted many researchers to understand the significance of arc-parallel shearing and extension in the Himalayan orogeny in addition to the arc-normal convergence. Accurate determination of the ongoing convergence rate across any segment of the Himalaya is essential for an accurate assessment of the seismic hazard and risk associated with that region. The convergence rate is assumed to be equal to the strain accumulation rate on the locked portion of Main Himalayan Thrust (MHT) which gets mostly released during earthquakes as slip along discrete faults, thus assuming insignificant inelastic deformation. Throughout various segments of Himalayan arc, several campaign and permanent mode GPS studies have been carried out in the past to accurately and precisely estimate the rates of ongoing arc-normal and arc-parallel convergence between the Indian Plate and southern Tibet.
A comprehensive literature review suggested that although across most of the segments along the Himalayan arc reliable estimates of strain accumulation rates are available, it is not the case with the Himachal region of NW Himalaya. Furthermore, the Himachal region exhibits the widest structural re-entrant in Kangra region than anywhere else along the Himalayan arc (Fig 2a - Refer Text) with significant slip partitioning taking place along multiple frontal and hinterland out-of-sequence faults. Such structural variations can possibly influence the short-term strain accumulation behaviour on the MHT. With these perspectives in sight, a network of 14 Permanent GNSS stations was established in the Himachal Himalaya after taking into consideration the regional active fault distribution (Fig 2b-c - Refer Text), the results of which are presented in this dissertation.
This study reports the results of continuous GPS measurements from 10 of these sites and analyze them along with the previously published results to constrain the ongoing arc-normal and arc-parallel convergence rates at 16.5±1.1 mm/yr and 4–5 mm/yr respectively. The Main Himalayan Thrust (MHT) is found to be strongly coupled up to ~100 km from the Main Frontal Thrust (MFT) but displays significant variation in coupling in the transition zone across the Kangra re-entrant and the adjoining western salient. This suggests that the long-term geological structures are possibly influencing the short-term strain accumulation behaviour on the MHT. Joint analysis of the coupling variation, the geologically inferred MHT geometry variations and the local topographic anomaly pattern strongly suggests the possibility of a potentially active, strain accumulating segment of MBT along the southern margin of Dhauladhar ranges in Western Himachal region.
This tectonically active segment of MBT is also proposed to influence the long-term topographic growth in the region. Although a general agreement is observed between the long-term shortening rates along the active faults and the estimated geodetic convergence in this region, the ensuing discussion highlights their complex relationship in terms of temporal and spatial variability in the fault activity and elastic-inelastic deformation. The fault orientation and the estimated convergence rate from this study is used to geometrically constrain a mean dextral slip-rate of 4.4–5.7 mm/yr along a recently discovered Khetpurali-Taksal fault (KTF) which most possibly experienced displacement during the 1905 ~Mw7.8 Kangra earthquake. This fault is suggested to partition most of the arc-parallel strain along itself in the study region. The N-S trending eastern segment of KTF is proposed to mark a fault segment boundary that separates the Central segment (Kumaun-Garhwal) of the seismogenic locked MHT from its Northwest (NW) (Himachal region) segment and possibly causes the change in the strain accommodation pattern observed in the highly distributed deformation pattern along multiple faults in the frontal portion of Himachal Himalaya compared to the adjoining Kumaun-Garhwal Himalaya.
The influence of arc-normal compression is clearly observable in the elevated topography of the Himalaya, but the effects of arc-parallel shearing are rather obscure or difficult to infer from its topography. In order to study the influence of the arc-parallel shearing and the varying obliquity of convergence evident by GPS studies in the topographic expression of NW Himalaya, a series of topography-based investigations were carried out using a model for the Himalaya developed by fitting a small circle arc to its southernmost deformation front and constructing a series of arc-normal topographic profiles at regular intervals. I incorporated a considerable along-arc stretch of the Himalaya consisting of Himachal, Kumaun-Garhwal, Nepal, Bhutan and eastern Assam segments that enabled comparative analysis of the attributes under consideration. Using this topographic model, I analyzed the topographic highs and lows relative to an estimated average arc-normal topographic profile, the directional derivatives of slope along the arc-parallel and arc-normal direction, and the deviation of the maximum gradient azimuth from the arc-normal direction for the portion of the Himalayan arc taken into consideration. The results suggest that the obliquity in convergence is a significant controlling factor in shaping the morphology of the Himalayan Slopes and the Himalayan topography has evolved in close alignment with the varying obliquity of convergence throughout the Himalayan arc. ~4±3 mm/yr of arc-parallel dextral shear is estimated to have been accommodated within the accretionary wedge spanning the NW Himalaya (particularly the part in Himachal & Garhwal) since the onset of arc-parallel shearing and extension during Middle Miocene. The subsequent analytical discussion in the light of previous studies conducted in the region suggests that a significant portion (~50-55 %) of the total arc-parallel dextral shear resulting from the ongoing convergence between the Southern Tibet and the Indian Plate is accommodated within the Himalayan accretionary wedge and the remaining is accommodated along the Karakoram fault system. The outcomes of the topographic investigations can only be explained with the predictions of the oblique convergence model and thus supports this model to explain the observed Himalayan deformation rather than the other proposed models such as Oroclinal Bending model, Radial Spreading model and the Lateral Extrusion (of Tibet) model. The observed correspondence of the locations of the underthrusting Delhi-Haridwar, Faizabad and Monghyr-Saharsa ridges with the varying pattern of arc-parallel shear accommodation, the topographic anomaly variations and the distribution of prominent active oblique, strike-slip and normal faults along the Himalayan arc suggests a significant role for the underthrusting ridges inherited from the Indian Plate in influencing the deformation of the overlying Himalayan accretionary wedge.
Ultimately, the results of the GPS studies and the past paleoseismological studies in the Himachal region of NW Himalaya are used to evaluate the strain budget for this region which suggests that ~9.3 m of strain has been accumulated in this segment since the inferred last great earthquake in 15th century which most possibly ruptured the entire Himachal segment of locked MHT. This ~9.3 m of accumulated strain is potent enough to generate a future great earthquake of magnitude ~Mw8.4. The possible recurrence interval for great (M>8) magnitude earthquakes is inferred to be ~600 years, which suggests a significantly elevated seismic hazard for the Himachal region of NW Himalaya.
... 11 ). Locally, the expression of surface ruptures can be highly variable, implying frequent hanging wall collapses, fault-related fold scarps, or pressure ridges [12][13][14][15][16] , which complicates the quantification of displacement. In the case of historical and paleo-earthquakes ruptures along megathrusts systems, identifying and quantifying surface ruptures are even more difficult. ...
Large earthquakes breaking the frontal faults of the Himalayan thrust system produce surface ruptures, quickly altered due to the monsoon conditions. Therefore, the location and existence of the Mw8.3 1934 Bihar–Nepal surface ruptures remain vividly disputed. Even though, previous studies revealed remnants of this surface rupture at the western end of the devastated zone, ruptures extent remains undocumented in its central part. Evidence for recent earthquakes is revealed along the frontal thrust in this region. The Khutti Khola river cuts an 8 m-high fault scarp exposing Siwalik siltstone thrusted over recent alluvial deposits, with faults sealed by a colluvial wedge and undeformed alluvial sediments. Detrital charcoals radiocarbon dating reveals that the last event occurred between the seventeenth century and the post-bomb era, advocating for the 1934 earthquake as the most recent event. In the hanging wall, fluvial terraces associated with fault scarps were abandoned after a penultimate event that happened after the tenth century, a rupture we associate with the historic earthquake of 1255CE. Slips of 11–17 m and 14–22 m for the 1934 and 1255 earthquakes, respectively, compare well with the ~ 10–15 m slip deficit accumulated between the two earthquakes, suggesting that most of the deformation along the front is accommodated by surface-rupturing earthquakes.
... The seismicity is experienced up to about 20 km depth in the Tibetan plateau, indicating shallow crustal deformation. Thrusting as a process accommodates about 90% of slip along the margin of the Tibetan Plateau in the Himalayas and the Altyn-Tagh (Kaneda et al. 2008), the central part being generally aseismic (Zhang et al. 2004). In the last 20 years, three major earthquakes were recorded in the Tibetan Plateau (Feng et al. 2011). ...
The Himalayan mountain range is sub-divided into four principal tectonic zones, from south to north. These are the Sub-Himalaya, the Lesser Himalaya, the Higher Himalayan Crystallines, and the Tethyan Himalaya. The Sub-Himalaya, also known as the Shiwalik Range (250–800 m high), rises above the Indo-Gangetic Plains along the Main Frontal Thrust. The Higher Himalayas, also known as the Central Crystalline zone, are comprised of ductile deformed metamorphic rocks and mark the axis of orogenic uplift. Mica schist, quartzite, paragneiss, migmatite, and leucogranite bodies characterize this uppermost Himalayan zone. Corresponding mineral assemblages are dominated by biotite to sillimanite, representing greenschist to amphibolite facies deformation. The Higher Himalayan Crystalline rocks have imbricated thrust sheets, with the grade of metamorphism increasing from the Chail Group to the Vaikrita Group. The Chail Group consists of a metamorphosed sequence of greenschist facies including phyllites, phyllitic quartzite, psammitic schists, orthoquartzites, arkose, chlorite schist limestones, and metabasic rocks amphibolites. The Sub-Himalaya range consists predominantly of Tertiary and Quaternary sediments and is bounded to the north by northward dipping Main Boundary Thrust, separating it from the overlying Lesser Himalaya. The Lesser Himalayan Range, in general, is quite rugged and higher than 2500 m, however, in the Kashmir Valley (Northwestern Himalaya), the Pir Panjal Range rises to above 3500 m. The Lesser Himalayas consists of Precambrian and Cambrian sequences of the Damtha, Tejam, Jaunsar–Garhwal, and Mussoorie Group in Garhwal region of the western Himalaya. The Mussoorie Group is represented by a persistent horizon of conglomerate intercalated with graywackes and siltstones at the base, which pass into carbonaceous slates and varicolored limestone. This succession is followed stratigraphically by carbonate-limestone, marl, slate, dolomite horizon in the middle and shale, conglomerate interbedded with phosphatic carbonaceous–pyritous slates, black limestone, and pyritous and felspathic quartzite in the upper portion. The Tethyan Himalayas consist of thick, 10–17 km, marine sediments that were deposited on the continental shelf and slope of the Indian continent. The Shiwalik zone consists of clastic sediments that were produced by the uplift and subsequent erosion of the Himalayas and deposited by rivers. These rocks have been folded and faulted to produce the Shiwalik Hills that are at the foot of the great mountains. Sub-Himalayan rocks have been overthrust by the Lesser Himalayas along the Main Boundary Thrust Fault. It not only shows geological divisions within the mountain belt, but also structures and geologic relationships between rock types and structures.KeywordsDuars (Piedmonts)Geological features of HKHGeological mappingQuaternary depositionTectonic framework
... The largest earthquakes documented near the study area are the 25AD Taxila earthquake with a maximum estimated intensity of IX on the (MMI) [84]; the 1974 Pattan earthquake with an estimated intensity of VIII on the MMI scale [85,86]; and the 1977 Rawalpindi earthquake with an estimated intensity of VII on the (MMI) [87]. Furthermore, the study area experienced a massive earthquake with a magnitude of (Ms 7.6) in 2005, which was caused by a portion of (MBT) regional boundary fault in the Kashmir area northeast of Islamabad [88][89][90]. It is worthwhile to mention that during the 2005 earthquake, the Rawalpindi-Islamabad area suffered significant structural damage, including the collapse of a massive 16-story apartment complex (Margala Tower), which led to the death of over 70 civilians (https://tribune.com.pk/story/269546/earthquake-2005 ...
Land subsidence is a major concern in vastly growing metropolitans worldwide. The most serious risks in this scenario are linked to groundwater extraction and urban development. Pakistan’s fourth-largest city, Rawalpindi, and its twin Islamabad, located at the northern edge of the Potwar Plateau, are witnessing extensive urban expansion. Groundwater (tube-wells) is residents’ primary daily water supply in these metropolitan areas. Unnecessarily pumping and the local inhabitant’s excessive demand for groundwater disturb the sub-surface’s viability. The Persistent Scatterer Interferometry Synthetic Aperture Radar (PS-InSAR) approach, along with Sentinel-1 Synthetic Aperture Radar (SAR) imagery, were used to track land subsidence in Rawalpindi-Islamabad. The SARPROZ application was used to study a set of Sentinel-1 imagery obtained from January 2019 to June 2021 along descending and ascending orbits to estimate ground subsidence in the Rawalpindi-Islamabad area. The results show a significant increase (−25 to −30 mm/yr) in subsidence from −69 mm/yr in 2019 to −98 mm/yr in 2020. The suggested approach effectively maps, detects, and monitors subsidence-prone terrains and will enable better planning, surface infrastructure building designs, and risk management related to subsidence.
... The only surface rupture observed in the field for a Himalayan earthquake was linked to the 7.6 Mw 2005 Kashmir earthquake, but was along the MBT (Kaneda et al., 2008). Even for the 8.4 Mw 1934 Eastern Nepal earthquake or the 8.4 Mw 1950 Assam earthquake, no direct observations of their surface ruptures were archived, and they were only inferred from trenching studies performed by Sapkota et al. (2013) and Priyanka et al. (2017). ...
... Medium earthquake ruptures, typically Mw ≤ 7.8, only extend along a portion of the seismological MHT. They either reach the surface out-ofsequence, similar to the 2005 Kashmir earthquake (Kaneda et al., 2008), or end several tens of kilometres north of the MFT, similar to the 2015 Gorkha earthquake (Avouac et al., 2015). Their slip is larger than 4 m and locally reaches up to 9.6 m (Pathier et al., 2006) or 7 m (Grandin et al., 2015) (the Kashmir and Gorkha earthquakes, respectively). ...
The morphological boundary between the Himalayas and the foreland plain is well expressed and most often corresponds to the frontal emergence of the Main Himalayan Thrust (MHT). This boundary is affected by surface ruptures during very large Himalayan earthquakes (Mw > 8) that regularly induce (with a recurrence of the order of 500 to 1200 years) the uplift of the foothills relative to the plain.
However, a thrust-fold system is hidden beneath the plain and is displayed by the seismic profiles of oil companies in east/central Nepal and by H/V passive geophysical techniques in Darjeeling. Its long-term kinematic evolution is slow, with a tectonic uplift of the hanging wall that is lower than the subsidence rate of the foreland basin, that is, less than approximately half a millimetre per year. During phases of low sedimentation controlled by climatic fluctuations, the morphological surfaces of the piedmont are incised by large rivers for several tens of metres; therefore, structures hidden under the sediments emerge slightly in the plain.
The evolution of the hidden structures corresponds to an embryonic thrust belt mainly affected by a long-term shortening rate of 1.4 +2.5/−1.2 mm·yr⁻¹, that is, 2–20% of the shortening rate of the entire Himalayan thrust system. Nonetheless, the details of the deformation associated with the embryonic thrust belt are still poorly understood. Several deformation components could affect the central Himalayan and Darjeeling piedmonts. i) Any slow steady-state deformation, such as layer parallel shortening (LPS) is not detected by Global Navigation Satellite System (GNSS) data, and such deformation would therefore absorb less than 0.5 mm·yr⁻¹. The geodetic data that suggest the aseismic growth of some of the structures are highly controversial. ii) For the rest of the deformation of the embryonic thrust wedge, it is yet to be proven whether deformation occurs during rare great earthquakes affecting the piedmont during medium earthquakes and/or during post-seismic deformation related to great earthquakes. The amplitude of this long-term low deformation is too limited to significantly reduce the seismic hazard in the seismic gaps of the Himalayan belt. iii) In some portions of the Himalayan front, such as Darjeeling (India), the thrust deformation related to great earthquakes propagates several tens of kilometres south of the morphological front in the zone previously affected by the long-term low deformation. It induces multi-metre surface ruptures in the piedmont and a mean shortening of 8.5 ± 6.2 mm·yr⁻¹. iiii) Pre-existing faults in the bedrock of the Indian craton, often oblique to the Himalayan structures, are locally reactivated beneath the foreland plain with low deformation rates.
