Uplift Rates Research Articles

Uplift and exhumation of the Chakabeishan ore district in the northern margin of the Qaidam Basin, China: Constraints from fission track thermochronology

The Chakabeishan area is located in the northern margin of the Qaidam Basin, Northwest China, and is an important lithium mining area. However, there is a relatively lower research degree and lack of data constraints of tectonic uplift and exhumation. Using fission track technology, new apatite and zircon fission track results have been reported for the first time in order to reveal the tectonic processes and uplift histories of this area. A total of 11 sample results were obtained, these ages could be divided into four groups, namely, 159–144 Ma, 114–100 Ma, 72 Ma and 52–32 Ma, revealing four periods of tectonic activities. Thermal history modelling provided three episodes of uplift at 120–60 Ma, 60–18 Ma and 18–0 Ma. In the first stage, the Southern Qilian Mountains was reactivated and subducted southward due to collision of the Lhasa and the Qiangtang blocks, resulting in rapid uplift in this area. The second stage is tectonic quiescence period corresponding to a relatively steady uplift. The third stage showing rapid uplift caused by the collision between the Indian and Eurasian Plates. The average uplift rate and total uplift amount of the three stages calculated according to the geological thermal histories are 0.039 km/Myr and 3.27 km, respectively. Using the age–closure temperature method, the exhumation rate has been calculated as 0.034–0.148 km/Myr from zircon closure–temperature of 250 °C to apatite closure–temperature of 100 °C and 0.049–0.076 km/Myr form the apatite closure–temperature of 100 °C to 15 °C of surface temperature. The exhumation rate is fastest from the Late Cretaceous to Eocene and has then changed a little since the Eocene, with the average exhumation rate of about 0.059 km/Myr. Synthesizing the zircon ages and geological characteristics, this area is characterized by multi–stages mineralization, and the metallogenic age is mainly in the Late Jurassic–Cretaceous.

The sea level rose fast, but Sarawak was rising faster

Since the end of the last glacial period, around 15550 years ago, melting ice caused the sea level to rise on average by about 110 m, or 7 mm/year. Data collected at the Tusan Cliff section indicate that during the same time span, the Borneo coastline south of Miri was elevated by 132 m. The average rate of uplift of the coastline was estimated to be in the order of 8.5 mm/year, which exceeded the average rate of sea level rise by 1.5 mm. As a result, a prominent cliff section is now exposed. The uplift may be continuing today but may be outpaced in the future by a much faster sea-level rise.

Probabilistic projections and past trends of sea level rise in Finland

Abstract. We explore past trends and future projections of mean sea level (MSL) at the Finnish coast, in the northeastern Baltic Sea, during the period 1901–2100. We decompose the relative MSL change into three components: regional sea level rise (SLR), postglacial land uplift, and the effect of changes in wind climate. Past trends of regional SLR can be calculated after subtracting the other two components from the MSL trends observed by tide gauges, as the land uplift rates obtained from the semi-empirical model NKG2016LU are independent of tide gauge observations. According to the results, local absolute SLR trends are close to global mean rates. To construct future projections, we combine an ensemble of global SLR projections in a probabilistic framework. In addition, we use climate model results to estimate future changes in wind climate and their effect on MSL in the semi-enclosed Baltic Sea. This yields probability distributions of MSL change for three scenarios representing different future emission pathways. Spatial variations in the MSL projections result primarily from different local land uplift rates: under the medium-emission scenario RCP4.5/SSP2-4.5, for example, the projected MSL change (5 % to 95 % range) over the 21st century varies from −28 (−54 to 24) cm in the Bothnian Bay to 31 (5 to 83) cm in the eastern Gulf of Finland.

Thermomechanical modelling of lithospheric slab tearing and its topographic response

Lithospheric slab tearing, the process by which a subducted lithospheric plate is torn apart and sinks into the Earth’s mantle, has been proposed as a cause for surface vertical motions in excess of 100 s of meters. However, little is known about the mechanisms that help initiate and control the propagation of slab tearing and the associated uplift. This study aims to explore these processes by means of 3D thermo-mechanical geodynamic modelling of a slab retreat oblique to a continental margin, using the Gibraltar Arc region (Betic Cordillera) as a scenario for inspiration. Our results suggest that the obliquity of the continental passive margin relative to the subduction trench leads to an asymmetric distribution of subduction forces and strength, facilitating the initiation of slab tearing. The model results predict a lateral migration of the tearing point at a velocity ranging between 38 and 68 cm/yr for a sublithospheric-mantle viscosity of up to 1e+22 Pa s. This fast slab tearing propagation yields uplift rates of 0.23–2.16 mm/yr above the areas where the subducted slab is torn apart, depending on mantle viscosity. Although a more detailed parametric exploration is needed, this range of uplift rates is compatible with the uplift rates required to overcome seaway erosion along the Atlantic-Mediterranean marine corridors during the Late Miocene, as proposed for the onset of the Messinian Salinity Crisis.

Geological and biotic context of the Plio-Pleistocene evolution of the Caucasus-Caspian Region (Akchagylian transgression)

We discuss geological and biotic aspects of the extensive Akchagylian transgression that occurred in the Caspian region of Eurasia near the Plio-Pleistocene transition, in Piacenzian and Gelasian. It is shown that the onset of the Akchagylian marine sedimentation in Western Turkmenistan (ca. 3.2 Ma) preceded that in the Kura Basin (ca. 3.0 Ma). The position of the upper boundary of the Akchagylian remains uncertain (ca. 2.1 or 1.8 Ma). The analyzed biotic content of the Akchagylian includes molluscs, microfossils (pollen, dinocysts, foraminifers), and mammals. It is noted that specific forms of the Akchagylian aquatic biota co-occur with microfossils that clearly indicate a connection with the World Ocean or related seas. The palynology of the Akchagylian time signals a directed cooling in the Pliocene and Early Pleistocene with several warm and humid epochs. The Akchagylian transgression was preceded by a change of a structural-sedimentary pattern of the region. In the latest Miocene and Early Pliocene, a pre-existed longitudinal tectonic zonation of the Caucasian-Caspian segment of the Paratethys gradually changed into clearly transverse tectonic zonation. The latter was manifested in the tectonic uplift of the Greater Caucasus, its northern piedmonts and the Lesser Caucasus, and in the subsidence of the western parts of the South and Middle Caspian basins. The interplay of longitudinal and transverse tectonic features shaped the configuration of the Akchagylian brackish-water basin and controlled thickness of its deposits. It was the transverse zonation that dominated in the thickness pattern. The increasing role of the transverse zonation in the post-Akchagylian time is manifested in the magnitudes and rates of the Quaternary tectonic uplift. These parameters were calculated based on current heights of the top of the Akchagylian marine deposits in different parts of the basin. The highest magnitudes of uplift are found in the Eastern Caucasus (up to 1980 m on the NE slope and about 2500 m in the axial part) and in the west of the Lesser Caucasus in eastern Turkey (up to 1750 m). The maximum level of the Akchagylian transgression is estimated at 40–50 m above the present level of the World Ocean. We show a low probability of connection of the Akchagylian basin with the Mediterranean Sea or the Persian Gulf, and a high probability of its connection with the Arctic Ocean through the northern tributaries of the Kama River and the Pechora Basin in the NE of East European Plain.

Tracking surface and subsurface deformation associated with groundwater dynamics following the 2019 Mirpur earthquake

The Mirpur Mw 5.8 earthquake on September 24, 2019, produced extensive liquefaction-induced surface deformation (LISD) in the surrounding villages. Due to the complexity of seismic hazards and the occurrence of their effects on a large spatial scale, the resulting surface, and subsurface deformation are often poorly resolved. To cover spatially extended LISD, the PSInSAR technique provided subsidence and uplift rate values ranging from −110 to +145 mm/yr consistent with the spatial distribution of the mapped liquefaction features. The most prominent surface change occurred in Abdupur and Sang villages. GPR measurements were conducted to map the near-surface cracks produced by transported liquified sand into the shallow subsurface layers and other liquefaction features (elevated groundwater table, conductive clay pockets, fractures, sand dikes, and water-enriched zones). Thus, the GPR survey assisted in the reconstruction of these structural and hydrogeological features on the near surface. In addition, the highly vulnerable zones were identified and mapped using space- and ground-based remote sensing measurements supported by the field observations. The results highlight the effectiveness of the proposed novel approach for detailed assessment of the coseismic liquefaction-induced deformation on- and near-ground surfaces by identifying areas prone to failure during earthquakes and thereby can help with hazard mitigation.

Effects of drainage conditions and suction pressure on tensile response of bucket foundations: An experimental study

Suction buckets acting as supports for jacket structures may constitute a viable foundation solution for offshore wind turbines. While monopiles dominate the industry, suction buckets remain uncommon despite their advantages in transitional water depths. One of the reasons stems from challenges of achieving optimal design due to scarce experience and knowledge, as the mechanisms governing foundation response to different drainage conditions are poorly understood. This paper contributes with new insights into tensile behavior of suction buckets based on experimental evidence. A defining property of bucket foundations is the ability to withstand extreme uplift forces on account of suction, which represents the core subject of this study. All tests involved a medium-scale model installed in sand in a pressurized environment. A novel feature of this research consists of examining the relative importance of soil density. By varying the relative density (40–90%) and the uplift rate (0.05–500 mm/s), a full range of drainage and soil conditions was explored. Suction pressure generated during partially drained or fully undrained uplift tends to reach similar values regardless of initial relative density. This key finding demonstrates how the soil state is altered due to jacking installation and cyclic pre-shearing. Regression models are established to capture the dependency of tensile capacity and initial stiffness on uplift rate.

Geodetic and seismic constraints on contemporary deformation on the northeastern Tibetan plateau: Velocity and strain rate tensor analysis

The study of the velocity and strain rate of the northeastern Tibetan Plateau can explain its crustal deformation characteristics. Previous investigations have relied on mathematical interpolation in GPS velocity to obtain a continuous strain field; these approaches can be applied well to regions where the deformation is relatively smooth and are not entirely suitable for the northeastern Tibetan Plateau that is cut by several large strike-slip faults. Thus, this study incorporates seismic constraints into the GNSS velocity and strain analysis to obtain a more realistic deformation field and compares it with the uplift rate and the stress results in depth, it will provide a comprehensive view of contemporary deformation on the northeastern Tibetan Plateau. It shows that there are two prominent deforming zones localized on the middle segments of the Haiyuan and East Kunlun faults, which may result from the different strengths in fault segmentation. The velocity and strain rate in the four profiles show that the convergence strain obviously decay from ∼15.5 mm/yr and ∼ 15.48 nstrain/yr in the western Qilian Mountains to ∼5.73 mm/yr and ∼ 5.76 nstrain/yr in the eastern Long Zhong Basin, respectively. The comparison between the vertical uplift rate, SKS result, and strain rate field indicates that the northeastern Tibetan Plateau is not only dominated by crustal shortening corresponding to the topography and surface fault geometry, but also by the strain transfer of motion along these significant strike-slip faults accounting for the extrusion and growth of the Tibetan Plateau. Combined with recent seismological results, our results indicate that the deformation of the study region resembles that of the Tibetan Plateau and can be viewed as a combined process linking both NE- or NEE-directed crustal shortening, vertical uplift, lateral extrusion along strike-slip faults and partial melting or mantle upwelling at depth.

Erosion and weathering in carbonate regions reveal climatic and tectonic drivers of carbonate landscape evolution

Abstract. Carbonate rocks are highly reactive and can have higher ratios of chemical weathering to total denudation relative to most other rock types. Their chemical reactivity affects the first-order morphology of carbonate-dominated landscapes and their climate sensitivity to weathering. However, there have been few efforts to quantify the partitioning of denudation into mechanical erosion and chemical weathering in carbonate landscapes such that their sensitivity to changing climatic and tectonic conditions remains elusive. Here, we compile bedrock and catchment-averaged cosmogenic calcite–36Cl denudation rates and compare them to weathering rates derived from stream water chemistry from the same regions. Local bedrock denudation and weathering rates are comparable, ∼20–40 mm ka−1, whereas catchment-averaged denudation rates are ∼2.7 times higher. The discrepancy between bedrock and catchment-averaged denudation is 5 times lower compared to silicate-rich rocks, illustrating that elevated weathering rates make denudation more spatially uniform in carbonate-dominated landscapes. Catchment-averaged denudation rates correlate well with topographic relief and hillslope gradients, and moderate correlations with runoff can be explained by concurrent increases in weathering rates. Comparing denudation rates with weathering rates shows that mechanical erosion processes contribute ∼50 % of denudation in southern France and ∼70 % in Greece and Israel. Our results indicate that the partitioning between largely slope-independent chemical weathering and slope-dependent mechanical erosion varies based on climate and tectonics and impacts the landscape morphology. This leads us to propose a conceptual model whereby in humid, slowly uplifting regions, carbonates are associated with low-lying, flat topography because slope-independent chemical weathering dominates denudation. In contrast, in arid climates with rapid rock uplift rates, carbonate rocks form steep mountains that facilitate rapid, slope-dependent mechanical erosion required to compensate for inefficient chemical weathering and runoff loss to groundwater systems. This result suggests that carbonates represent an end member for interactions between climate, tectonics, and lithology.

Tectonic development of northeastern part of the Arabian Plate: Examples from Pirmam and Bana Bawi anticlines in the Kurdistan region of north Iraq

The Pirmam and Bana Bawi anticlines are two elongated anticlines located in the central northern part of the Kurdistan Region of north Iraq (KRI), in the northeastern part of the Arabian Plate. We have used satellite images and geological maps to interpret the presented data and to calculate the rates of uplift and down wards (subsidence) amounts, besides estimating the rates of deposition and incision of some alluvial fans and stream terraces. Most of the achieved data were checked in the field. In the Pirmam anticline the rate of the uplift and subsidence is 8.613 mm/ 100 year and 7.962 mm/ 100 year, respectively, whereas in the Bana Bawi anticline the rates are 3.036 mm/ 100 year and 4.365 mm/100 year, respectively. The indications of the lateral growth are the presence of water gaps, wind gaps, en-echelon plunging, whale-back shape and different types of valleys. We have calculated the depositional and incision rates in the Kori and Bastoora streams. They are 5.204 mm/ 100 year and 5.555 mm/ 100 year, respectively in the former, whereas in the latter are 3.469 mm/100 year and 8.731 mm/ 100 year, respectively. Moreover, we have calculated the depositional and incision rates in old and recent alluvial fans. In the former, they are 1.665 mm/ 100 year and 0.722 mm/ 100 year, respectively, whereas in the latter are 3.036 and 4.365 mm/ 100 years, respectively.

Causes of permanent vertical deformation at subduction margins: Evidence from late Pleistocene marine terraces of the southern Hikurangi margin, Aotearoa New Zealand

Theoretical studies of the seismic cycle at convergent plate boundaries anticipate that most coseismic deformation is recovered, yet significant permanent vertical displacement of the overriding plate is observed at many subduction margins. To understand the mechanisms driving permanent vertical displacement, we investigate tectonic uplift across the southern Hikurangi subduction margin, Aotearoa New Zealand, in the last ∼200 ka. Marine terraces preserved along the Wellington south coast have recently been dated as Marine Isotope Stage (MIS) 5a (∼82 ka), 5c (∼96 ka), 5e (∼123 ka) and 7a (∼196 ka) in age. We use these ages, together with new reconstructions of shoreline angle elevations, to calculate uplift rates across the margin and to examine the processes responsible for their elevation. The highest uplift rate—1.7 ± 0.1 mm/yr–and maximum tilting—2.9° to the west–are observed near Cape Palliser, the closest site to (∼50 km from) the Hikurangi Trough. Uplift rates decrease monotonically westward along the Palliser Bay coast, to 0.2 ± 0.1 mm/yr at Wharekauhau (∼70 km from the trough), defining a gently west-tilted subaerial forearc domain. Locally, active oblique-slip upper-plate faults cause obvious vertical offsets of the marine terraces in the axial ranges (>70 km from the trough). Uplift rates at Baring Head, on the upthrown side of the Wairarapa-Wharekauhau fault system, are ∼0.7–1.6 mm/yr. At Tongue Point, uplift on the upthrown side of the Ōhāriu Fault is 0.6 ± 0.1 mm/yr. Dislocation and flexural-isostatic modelling shows that slip on faults within the overriding plate—specifically the Palliser-Kaiwhata Fault and the Wairarapa-Wharekauhau fault system—may dominate uplift in their immediate hanging walls. Depending on their slip rate and geometry, slip on these two upper-plate fault systems could plausibly cause >80% of late Pleistocene uplift everywhere along the south coast of North Island. Our modelling suggests that subduction of the buoyant Hikurangi Plateau contributes uplift of 0.1–0.2 mm/yr and uplift due to sediment underplating at Tongue Point and Wharekauhau is likely ≤0.6 mm/yr but could be significantly lower. Earthquakes on the subduction interface probably contribute ≤0.4 mm/yr of late Pleistocene uplift, with ≤10% of uplift due to each earthquake being stored permanently, similar to other subduction zones. These results indicate a significant contribution of slip on upper-plate faults to permanent uplift and tilting across the subduction margin and suggest that in regions where upper-plate faults are prevalent, strong constraints on fault geometry and slip rate are necessary to disentangle contributions of deeper-seated processes to uplift.

Climate control on the relationship between erosion rate and fluvial topography

Abstract Conceptual and theoretical models for landscape evolution suggest that fluvial topography is sensitive to climate. However, it remains challenging to demonstrate a compelling link between fluvial topography and climate in natural landscapes. One possible reason is that many studies compare erosion rates to climate data, although theoretical studies show that, at steady state, climate is encoded in the relationship between erosion rate and topography rather than erosion rate alone. We use an existing global compilation of 10Be basin-averaged erosion rates to isolate the climate signal in topography as a function of erosion rate for morphologically steady-state, fluvially dominated basins underlain by crystalline bedrock. Our results show that the relationship between erosion rate (a proxy for rock uplift rate) and the normalized river channel steepness index (a proxy for fluvial relief) becomes increasingly nonlinear with increasing mean annual precipitation and decreasing aridity. This result indicates that erosional efficiency increases in wetter and more humid climates, lowering fluvial relief for a given erosion rate. When interpreted in the context of detachment-limited bedrock incision models that account for incision thresholds and stochastic flood distributions, this systematic pattern can be explained by a decrease in discharge variability in wetter and more humid landscapes, assuming incision thresholds are important on a global scale.

The vertical velocity field of the Tibetan Plateau and its surrounding areas derived from GPS and surface mass loading models

Obtaining a precise velocity field of the Earth's surface is critical for probing Earth's tectonic movements. In this contribution we construct a precise vertical velocity field with high-spatial resolution for the Tibetan Plateau (TP) and its surrounding areas using both 113 continuous and 969 campaign GPS time series over the period 2008 to 2019. Specifically, we compared the statistical distribution of residual continuous GPS time series to find the optimal regional surface mass loading (SML) models. The optimal modeled nontectonic displacements were used to correct these campaign GPS time series to reduce their scatter and accordingly improve the precision of the uplift rate estimates. The results showed that we could reduce the root mean square (RMS) on the vertical coordinate time series by more than 75% of the campaign GPS stations. We computed and removed vertical deformation due to horizontal strain rates obtained from GPS time series, and discussed dynamic sources (mantle dynamic topography, isostatic adjustment, and flexural loading) that drive the residual vertical tectonic motion. The study presents the most recent surface kinematic constraints for comprehending the dynamic sources of tectonic uplift or subsidence between and within tectonic units.Plain Language Summary: Movements of the Tibetan Plateau (TP) have a profound impact on adjacent areas. We collected all available GPS data to determine a precise vertical velocity field with high-spatial resolution. We make use of optimal surface mass loading (SML) models to improve estimation accuracy of campaign GPS stations, including an estimate of the vertical movement caused by the horizontal tectonic motions. We combine geological and geophysical data with our vertical velocity field to understand the dynamic sources of uplift or subsidence between and within tectonic units of the TP.

Quaternary Map, Active Faulting, Tectonic Geomorphology, and Uplift Rate of the Humboldt Range in the Basin and Range Province of Nevada, United States

ABSTRACT Fault-truncated, uplifted, and abandoned alluvial fans are frequent along the western flank of the active normal fault bounded Humboldt range. Terrestrial cosmogenic nuclide surface exposure dating of a faulted terrace at Rocky Canyon indicates that uplift of the range has averaged about 0.12 mm/yr during the last ∼160 ka. A similar uplift rate of less than about 0.07 mm/yr over the last 35 ka or more years is estimated from offset of a younger terrace at the same site. Values of extension rate across the range are 0.04–0.07 mm/yr, if it is assumed that the range-bounding fault dips at 60°, in general accord with very low values of contemporary geodetic strain reported for the area. Geomorphology at Rocky Canyon records a period leading up to about 160 ka ago that erosion and aggradation of sediment along the rangefront were dominant over fault generated uplift, at which time faulting again became dominant, leading to uplift, incision, and preservation of ∼160-ka-old alluvial terraces here and elsewhere along the rangefront.

Detrital zircon U[sbnd]Pb geochronology of modern river sediment in the Eastern Pamir Syntaxis and its implications for the formation of the Pamir and growth of the Tibetan Plateau

The Eastern Pamir Syntaxis links the western Tibetan Plateau with the western syntaxis of the Himalayan-Tibetan orogen. Quantifying temporal and spatial variations in uplift rates for the Eastern Pamir Syntaxis is critical for understanding the growth of the Himalayan-Tibetan orogen. To better understand these variations, we report n = 285 new detrital zircon UPb ages from sediments in modern rivers of the Eastern Pamir Syntaxis. When compared with previous work, our data, with a major age mode around ∼107 Ma, indicate that siliciclastic sediments in the Taxkorgan River were primarily derived from Cretaceous rocks. Whereas a less prominent age mode around ∼13 Ma suggests that Miocene rocks made an important sediment contribution to the Taxkorgan River. The other notable age modes are in the range of 200–300 Ma and 600–800 Ma. Our data suggest that detrital zircon UPb signatures for rivers draining the Eastern Pamir Syntaxis change significantly from south to north, and the influence of Cretaceous proto-sources gradually diminishes northward. Because Tibetan sutures are traceable into the Pamir, these data help define the distribution of late Early Cretaceous rocks associated with the closure of the Meso-Tethys within the Pamir. These data support the establishment of the modern-like river pattern in the Eastern Pamir Syntaxis contemporaneous with activity on the Kongur Extensional System in the northeast Pamir.

Coastal cliff evolution: Modelling the long-term interplay between marine erosion, initial topography, and uplift in an arid environment

Coastal cliff evolution is modulated by several factors, such as uplift, marine erosion, previous topographical conditions, and changes in global sea level. In this study, a numerical model is used to understand the influence of these processes on the evolution of coastal cliffs. This model is based on erosional and tectonic conditions of the Great Coastal Cliff in the Atacama Desert, the tallest and most uninterrupted coastal cliff on Earth. The results show that a faster uplift rate (> 0.3 mm/yr) or an older onset of uplift (3 Myrs) favors the formation of inactive cliffs, whereas active cliffs preferentially form under conditions of a slow uplift (0.2 mm/yr) or a younger uplift onset (1 Myr). Low erosion rates (< 1 m2/yr) also favor the preservation of sequences of staircase marine terraces, separating the seashore from an inactive coastal cliff. In contrast, high erosion rates (≥ 1 m2/yr) inhibit marine terrace formation, keeping the cliff active. The effect of erosion on cliff activity is enhanced or reduced by the slope of the initial topography. Steep coasts (> 5–10°) may hamper cliffs from reaching an inactive state. Thus, this model gives insights on the relative importance of these variables on the development of active and inactive cliffs, especially in an environment such as the Atacama Desert in northern Chile.

Spatial and Temporal Analysis of Geologic Slip Rates, Cucamonga Fault, California, USA: Implications for Along‐Strike Applications and Multi‐Fault Rupture

AbstractTo constrain fault processes and hazard, fault slip rates may be extrapolated over different fault lengths or time intervals. Here, we investigate slip rates for the Cucamonga Fault (CF). The CF is located at the junction of the Transverse Range fault system with the San Andreas and San Jacinto Faults, and it is hypothesized to connect with these faults, promoting the propagation of large, multi‐fault earthquakes. Previous work has shown that CF displacements on late Quaternary alluvial fan surfaces are highly variable along strike. We present two new 10Be surface exposure ages from depth profiles on the alluvial fans. Slip rates are consistent with a rate of 1.4 ± 0.3 m/kyr over time intervals of ∼20, ∼30, and ∼40 kyr. If the CF participates in multi‐fault ruptures, then these earthquakes occur either rarely or with sufficient regularity to maintain apparently steady rates over multiple intervals. We also explore along‐strike fault displacement variability using a calibrated morphological model. The model successfully reproduces scarp profiles and indicates that fault displacement variability can be explained in part by scarp age but not uplift rate. We infer that both erosion by ephemeral gullying and distributed deformation contribute to fault displacement variability, although both are difficult to detect confidently without excavations across the scarp. These investigations show that better characterization of cumulative‐slip variability along strike may improve accuracy and precision of slip rates. Slip rates that do not consider epistemic uncertainties may not be suitable for extrapolation over longer fault sections.

Quantifying the influence of asymmetric uplift, base level elevation, and erodibility on cross-divide χ difference

It is generally accepted that a river long profile contains both temporal and spatial signals on uplift rate. The uplift history (temporal variation) inferred from the channel profile will be substantially affected by spatial variation of the uplift rate. Therefore, knowing the spatial variation in uplift rate is the premise of obtaining a reliable uplift history. The χ-plot approach is widely used as a substitute for a channel profile when extracting tectonic information from topography. Theoretically, when a drainage divide is at a steady-state, the cross-divide difference in χ values is controlled by the uplift rate and erosion coefficient of bedrock. However, how the spatial variation in uplift rate and lithology influence the cross-divide difference in χ values is still unclear. In this study, we derive an analytical solution to quantify the influence of spatially variable rock uplift rate, erosion coefficient, outlet elevation, and drainage-basin morphology on cross-divide χ difference. We then use numerical landscape evolution models with different uplift rate ratios, erosion coefficients, and base level elevations, across drainage divides, to test the equation. The cross-divide χ ratios in the numerical models are broadly consistent with theoretical prediction, confirming reliability of the formula. We further apply the formula to two natural examples, showing its applications. In the Wula Shan case, the uplift rate ratio of its two boundary faults is ~0.20, and in the Xizhou Shan case, the main drainage divide is migrating southward according to the equation. The new equation improves the reconstruction of tectonics from channel profiles. Moreover, it extends the cross-divide comparison of χ values to more complex geological conditions for measuring the stability of drainage divides.

Crustal deformation study of Kashmir basin: Insights from PSInSAR based time series analysis

In the present study, the rate of deformation of the Kashmir basin has been determined using the Sentinel-1A based Persistent Scatterer Interferometry Synthetic Aperture Radar (PSInSAR). The study reveals highest rate of uplift in the Pir-Panjal range (8–13 mm/y) whereas, in the Saribal range the rate of upliftment is 5–6 mm/y. The line of sight displacement in the Kashmir basin was recorded in the range of −20 to +30 mm/y over the period of 2015 to 2021. However, the temporal displacement variation in the Kashmir valley varies in different years during the observation period and was found maximum in the year 2021. The Persistent Scatterer Interferometry (PSI) clearly show dominant uplift in the valley and surrounding hill ranges. The PSInSAR results were further validated with the GPS based deformation rates, which indicates a maximum of 10 mm/yr of deformation in the study area. The high / lows of gravity and magnetic based surveys are well corroborated with the observed positive and negative anomalies of present PSInSAR velocity results. Further, the Global Positioning System (GPS) based crustal strain results are also collectively substantiating our PSInSAR based crustal behaviour of the Kashmir basin.

Tectonic geomorphology of the Ottawa-Bonnechere Graben, Eastern Canada: implications for regional uplift and intraplate seismicity

In intraplate areas where regional tectonic strain is accommodated by the reactivation of pre-existing structures, the level of seismic hazard associated with faults may be underestimated due to the poor surface expression of faults, scattered earthquake distribution, and long earthquake recurrence intervals. The cause(s) of seismicity in eastern Canada remains unresolved. This is partially because surface expressions of faults have been eroded during glacial and deglacial periods and in the Ottawa-Bonnechere Graben (OBG) are undetectable until a seismic event. Morphotectonic analysis has been widely applied to assess relative tectonic activity in various geological settings. To establish whether active uplift is occurring and to investigate the spatial distribution of relative uplift rates, 131 bedrock drainage basins in OBG were analysed. The aim of this was to (1) test the applicability of geomorphic indices for quantifying active deformation, (2) quantify the spatiotemporal distribution of relative uplift rates, and (3) explore the implications for faulting mechanisms, deformation styles, and ultimately regional seismic hazard. We measured valley floor width-to-height ratio ( Vf), basin elongation ratio ( Re), basin hypsometric integral, and normalized channel steepness index ( ksn). The results show that high relative uplift rates exist in all the six bedrock escarpment sections investigated, suggesting that they are presumably related with regional broad wavelength uplift (epeirogeny) caused by a complex interaction between far-field tectonic stress and glacial isostatic adjustment (GIA). Our analysis showed that Vf, Re, and ksn reveals no considerable spatial differences in high relative uplift rates, consistent with the Canadian Base Network GPS uplift rates. Highlights Geomorphic indices are applied in a low relief and low-medium seismicity area. Geomorphic indices reveal a broad wavelength regional uplift and show relative tectonic activity in the OBG. Relatively high geomorphic indices values provide longer term deformation history compared to global positioning system (GPS) records. Landscape formation and river incision is driven by a complex interaction between GIA and far-field tectonic stresses. Relative uplift rate results show similar patterns to published GPS uplift rates. Possible link between relative tectonic activity and current seismicity.