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The Earth's crust is exposed by tectonic processes and is not static over time. Modelling of the Earth's surface velocities is of utmost importance for research in geodesy, geophysics, structural geology, and other geosciences. It may support positioning, navigation, seismic risk, and volcano notification services, for example. Space geodetic techniques can be used to provide high-quality velocities in a network of geodetic sites. Velocity field modelling should, however, expand the velocities from a discrete set of points to any location in-between. This paper presents four new methods for the Earth's surface velocity interpolation. Contrary to the widely used approach dividing the velocity field to the horizontal and vertical components, a full 3D interpolation approach is proposed based on the Delaunay triangulation and the n-simplex interpolation. The use of a combination of all three components is advantageous for geophysical interpretation. The proposed interpolation approach is entirely local but enables global modelling, which does not suffer from map projection distortions and singularities at the poles. Various global and regional position/velocity datasets are used to evaluate the performance of the proposed velocity interpolation methods. The latter provide practically the same results when applied to regional velocity field modelling. However, the so-called continuous piecewise quasi-radial 3D velocity field interpolation method is recommended for its favourable properties. It introduces an ellipsoidal Earth model, appropriately considers vertical/up and horizontal velocity components, tends to radial symmetry, and provides continuity for the interpolated velocity components as well as for the estimated uncertainties. [ABSTRACT FROM AUTHOR]

Plate tectonics theory, established in the 1960s, has been successful in explaining many geological phenomena, processes and events that occurred in the Phanerozoic. However, the theory has often struggled to provide a coherent framework in interpreting geological records in continental interior and Precambrian period. In dealing with the relationship between plate tectonics and continental geology, continental interior tectonics was often separated from continental margin tectonics in the inheritance and development of their structure and composition. This separation led to the illusion that the plate tectonics theory is not applicable to Precambrian geology, particularly in explaining the fundamental geological characteristics of Archean cratons. Although this illusion does not mean that the Archean continental crust did not originate from a regime of plate tectonics, it led to the development of alternative tectonic models, often involving vertical movements under a regime of stagnant lid tectonics, including not only endogenous processes such as gravitational sagduction, mantle plumes and heat pipes but also exogenous processes such as bolide impacts. These vertical processes were not unique to the Archean but persisted into the Phanerozoic. They result from mantle poloidal convection at different depths, not specific to any particular period. Upgrading the plate tectonics theory from the traditional kinematic model in the 20th century to a holistic kinematic-dynamic model in the 21st century and systematically examining the vertical transport of matter and energy at plate margins, it is evident that plate tectonics can explain the common geological characteristics of Archean cratons, such as lithological associations, structural patterns and metamorphic evolution. By deciphering the structure and composition of convergent plate margins as well as their dynamics, the formation and evolution of continental crust since the Archean can be divided into ancient plate tectonics in the Precambrian and modern plate tectonics in the Phanerozoic. In addition, there are the following three characteristic features in the Archean: (1) convective mantle temperatures were 200–300°C higher than in the Phanerozoic, (2) newly formed basaltic oceanic crust was as thick as 30–40 km, and (3) the asthenosphere had a composition similar to the primitive mantle rather than the depleted mantle at present. On this basis, the upgraded plate tectonics theory can successfully explain the major geological phenomena of Archean cratons. This approach provides a new perspective on and deep insights into the evolution of early Earth and the origin of continental crust. In detail, Archean tonalite-trondhjemite-granodiorite (TTG) rocks would result from partial melting of the over-thick basaltic oceanic crust at convergent plate margins. The structural patterns of gneissic domes and greenstone keels would result from the buoyancy-driven emplacement of TTG magmas and its interaction with the basaltic crust at convergent margins, and komatiites in greenstone belts would be the product of mantle plume activity in the regime of ancient plate tectonics. The widespread distribution of high-grade metamorphic rocks in a planar fashion, rather than in zones, is ascrible to separation of the gneissic domes from the greenstone belts. The shortage of calc-alkaline andesites in bimodal volcanic associations suggests the shortage of sediment accretionary wedges derived from weathering of granitic continental crust above oceanic subduction zones. The absence of Penrose-type ophiolites suggests that during the subduction initiation of microplates, only the upper volcanic rocks of the thick oceanic crust were offscrapped to form basalt accretionary wedges. The absence of blueschist and eclogite as well as classic paired metamorphic belts suggests that convergent plate margins were over-thickened through either warm subduction or hard collision of the thick oceanic crust at moderate geothermal gradients. Therefore, only by correctly recognizing and understanding the nature of Archean cartons can plate tectonics reasonably explain their fundamental geological characteristics. [ABSTRACT FROM AUTHOR]

The Java ‐ Lesser Sunda margin, which features multi‐scale subducting oceanic basement relief, is classified as neutral (Lombok and Sumbawa) to erosional (Central Java to Bali) in comparison to its accretionary counterpart offshore Sumatra. However, a comprehensive analysis of how plate boundary and upper plate structure across the neutral to erosional transition are modulated by the subduction of oceanic basement relief is lacking to date. To shed light on the tectonic parameters that push the margin into the neutral or erosional domain, we combine multi‐channel reflection seismic images derived through a grid‐based P‐wave velocity inversion, and multibeam bathymetric maps. The data document how different scales of subducting topography modify seafloor morphology, upper plate structure, and décollement position. Large‐scale subducting features cause a landward shift of the deformation front, shortening of the accretionary wedge, and seafloor steepening at the relief's trailing edge. Small‐scale subducting ridges primarily impact the frontal prism resulting in over‐steepening at the trench and localized slope failure. Ahead of subducting relief, deformation of the accretionary wedge encompasses enhanced compression and a reduction in seafloor slope but appears independent of the size of the relief. Ridge and seamount subduction induce frontal erosion and basal erosion offshore Lombok and Bali, respectively. Our P‐wave velocity models indicate that the rigidity of the upper plate's base along the eastern Sunda margin is significantly lower than the worldwide trend. We conclude that this favors the genesis of tsunami earthquakes that have occurred on the Java margin. Plain Language Summary: The convergence of the tectonic plates drives a wide variety of geological processes along the plate margins, including the formation of the forearc accretionary wedge, volcanic activities, and megathrust earthquakes. Over the past 40 years, marine research shows that different sizes of oceanic reliefs (seamounts and ridges) are widely distributed over the seafloor, approaching the trench, and eventually subducted underneath the overriding plate. An accurate observation of the subducted reliefs and their tectonic impact on the overriding plate depends on different observation approaches, data processing methods, and the evolutionary history of the forearc. In the Java margin, the oceanic seafloor features massive seamounts with different scales and shapes, and the bathymetry of the overriding plate is highly disturbed. This provides us with the best opportunity of studying the rugged seafloor's seismogenic and geological impacts. By using state‐of‐the‐art seismic imaging techniques, we image the subsurface structures, obtain the forearc velocity, identify the seamounts, and discuss the seamounts' effect on structural deformation and megathrust earthquake occurrence. Distinctively, the marine forearc gets shortened and thickened significantly by seamount subduction. Structural images sharply illustrate different deformation patterns and stress regimes at the seamount's different flanks and reveal the possible process of subduction erosion. Key Points: Upper plate deformation scales with variable subducting relief, as observed along the Java Trench in seismic sections and bathymetrySubduction of seafloor topography induces progression from an accretion‐dominated domain toward a phase of subduction erosionThe overall low rigidity of the upper plate's base may contribute to the Java margin earthquake's tsunami‐genesis [ABSTRACT FROM AUTHOR]

Based on comparison of morphotectonic analysis results with the SL index analysis, airborne geophysical measurements and field geological and structural data, possible Miocene to Holocene development of the landscape relief of Novohradské Mts. (southern Moldanubian Zone; Bohemian Massif) with a significant contribution of active faulting is interpreted. We suppose a polyphase reactivation of pre-existing faults under (a) the Miocene-Pliocene stress-field (regional ∼ NNW–SSE extension) as (oblique) normal faults trending ∼ SW–NE to ∼NW–SE were responsible for the subsidence of the Třeboň Basin and Kaplice Furrow and (b) the Pliocene to Holocene stress-field (Shmax = 146°) when horizontal in the ∼NNW–SSE direction with possible activity of the prevailing ∼ NNE-SSW trending faults as a sinistral strike-slips or weak reverse oblique-slip movement. The second set of subvertical ∼ WNW–ESE faults was predominantly reactivated in a dextral strike-slip regime or as gentle reverse oblique-slip faults. These Miocene to Holocene events reflect the coupling between the East-Alpine–Carpathian segment and its northern foreland, mainly due to northward motion of the African and the Arabian lithospheric plates. The core of the Novohradské hory Mts. experienced a significant uplift compared to the neighboring areas of the Kaplice Furrow and the Třeboň Basin. The most significant uplift has been found near Rychnov nad Malší, and on the tectonic border between the Kaplice Furrow and the Bukovský hřbet Ridge. This uplift took place during the late Pliocene and Pleistocene, after the sedimentation of lacustrine sediments in the Kaplice Furrow. Although the combination of GIS, morphotectonic and geophysical analyses with validation by field structural data does not provide the final proof of young tectonic activity, we conclude that there is strong indication of Neogene-Quaternary reactivation of several faults in the Novohradské Hory Mts. Based on similar morphological features, it can be supposed that many areas in the Alpine Foreland and Bohemian Massif underwent similar tectonic evolution during the Miocene to Holocene era. [ABSTRACT FROM AUTHOR]

A comprehensive study of geophysical, geological, tectonic, lithofacies, petrophysical and a number of other factors of oil and gas content and their changes in space over time make it possible to develop the foundations of the main criteria for predicting the distribution of oil and gas territories and the development of hydrocarbon deposits. In order to assess the prospects for prospecting for oil and gas accumulations and reduce the risks of ineffectiveness of exploration and further development and drilling operations in the lower section of the Productive Strata (PS) of the western side of the South Caspian Basin (SKV), based on the available material and taking into account the large number of published works, We considered the tectonic criteria and conditions for the preservation of the formed accumulations of hydrocarbons in the South Absheron archipelago, in the example of the Gum-Deniz and Bahar areas. By specifying the development of uplifts, tectonic faults and the lithofacies composition of more ancient sediments, paleostructural analysis can provide significant assistance in identifying promising areas for prospecting and exploration, and ultimately thereby significantly reduce the risks of inefficiency in drilling operations. [ABSTRACT FROM AUTHOR]

Tectonic tremor and low‐frequency earthquakes (LFEs) are two different representations of the high‐frequency (>1 Hz) components of broadband slow earthquakes, which have been discovered in various tectonic regions. Although LFEs are considered building blocks of tremor, it is difficult to find constituent LFEs for some long‐duration tremor sequences. Here we introduce a new scheme to synthesize an impulsive response from a tremor source, or empirical LFE (eLFE), from complex tremor sequences. The eLFE is constructed by maximizing the absolute amplitude (L∞ norm) of the normalized and stacked waveforms of many tremor sequences at many stations. This problem includes a highly multimodal objective function, which is maximized via a combined optimization method that incorporates a genetic algorithm and iterative improvements. We first apply this method to several validation tests using synthetic tremor waveforms and real LFEs, and then tremor activities where few nearby LFEs have been detected. One example is the Okayama tremor, which has been known to be extraordinarily sensitive to tidal stress. The eLFE is helpful in determining the accurate hypocentral location and recovering the long‐term comprehensive tremor activity via a matched‐filter analysis. The well‐constrained depth of the Okayama tremor sources is less than 30 km, which suggests that the subducting Philippine Sea Plate is very shallow at this distant location from the trench axis. This eLFE scheme highlights the fact that tremor sequences may be composed of random fluctuations that are not necessarily impulsive and emphasizes the importance of characterizing such randomness to better understand slow earthquake behavior. Plain Language Summary: Slow earthquakes are underground shear slip events that are similar to ordinary earthquakes but radiate weak seismic waves. The locations of these slow earthquakes are often close to the estimated source regions of past and future giant earthquakes, and may therefore be important in advancing our understanding of the genesis of hazardous earthquakes. Two types of slow earthquakes are tectonic tremors and low‐frequency earthquakes (LFEs), which have been discovered in various regions around the world over the past two decades. LFEs are often, but not always, identified within long‐duration tectonic tremor signals. It is generally easy to constrain the source location and elementary mechanism of LFEs since they are impulsive events. Therefore, it is desirable to find or extract LFEs from a given tectonic tremor sequence since they are rather easy to detect. Here we developed a new method to empirically synthesize LFEs for tremor sequences based on a statistical measure, and successfully applied it to some tremor activities. The method worked effectively, especially for the Okayama tremor, and significantly improved both the accuracy of the source location and the completeness of the regional tremor/LFE catalog. Key Points: We can synthesize the waveforms of an impulsive low‐frequency earthquake by stacking non‐impulsive continuous tremor recordsThe empirical low‐frequency earthquake is synthesized by maximizing the L∞ norm, which is solved via a multimodal optimization approachThe Okayama tremor is constrained to less than 30 km depth, suggesting a complex geometry of the subducting Philippine Sea Plate [ABSTRACT FROM AUTHOR]

Fault slip rates are critical to quantify continental deformation. Those along the Karakax fault (northwestern Altyn Tagh Fault: ATF) have been debated, even though it is one of Tibet's most outstanding active faults. At Taersa, using LiDAR measurements of terrace and fan riser offsets (∼6 to ∼500 m) and 10Be/26Al dating of alluvial surfaces (<210 ka), we obtain a late Quaternary slip rate of ∼2.5 ± 0.5 mm/yr. This doubles the ∼2.6 ± 0.5 mm/yr rate time span found to the east and west. We interpret the ∼150 km‐long, free‐faced rupture along the fault to be that of the M ∼ 7.6 event felt in Hotan in 1882. Characteristic slip (∼6 m) during four large earthquakes since ∼10 ka implies a ∼2500 ± 500 years return time. A ∼3 mm/yr rate is consistent with the ∼80 km offset of the Karakax river since uplift of the West Kunlun range and sediment deposition in the Tarim foreland accelerated, ∼24 Ma ago. The faster slip rate (∼10.5 mm/yr) on the central ATF matches the sum of those along the reactivated West Tibetan terrane boundaries (Karakax and Longmu‐Gozha Co faults) at the Uzatagh triple junction (∼36°N, 83°E). The abrupt termination and altitude drop of the Karakorum range where the Longmu Co and Karakorum faults meet (Angmong junction), also reflect triple junction kinematics. Such localized changes account for the rise of the Karakorum and West Kunlun ranges and support lithospheric block tectonics rather than diffusely distributed deformation. Plain Language Summary: How the Tibetan plateau rose to ∼4500 m and deforms today remain outstanding questions. Tibet's northern edge follows the ∼2000 km‐long ATF, whose westernmost branch is the Karakax fault. Despite the spectacular escarpments and offsets observed along that fault, its slip rate, critical to quantify continental deformation, has remained controversial. Here, we corroborate that, for the last ∼210,000 years, that rate has been ∼2.5 ± 0.5 mm/yr, based on high‐resolution topography and dating of left‐laterally offset fluvial surfaces. The ∼80 km offset of the Karakax river implies that this rate may have remained constant since the rise of the Kunlun range above the Tarim basin started ∼24 Ma ago. The sharp fault trace reflects the exceptional preservation, since ∼10,000 years ago, of four M ∼ 7.6 earthquake ruptures (the last in 1882), each with ∼6 m of slip (∼2500 years return time). Fault slip rates, GPS vectors and mountain altitudes across western Tibet reflect block motions and triple junction kinematics rather than continuum deformation. Specifically, localized velocity changes appear to account for the rise of the West Kunlun and Karakorum ranges. Our results bridge the gaps between present and long‐term geological history, and broad‐scale geodesy and local field evidence. Key Points: The ∼400 km‐long, left‐lateral Karakax fault (western Altyn Tagh fault) slip rate has been ∼2.5 ± 0.5 mm/yr for ∼210 kaFour M ∼ 7.6 earthquakes (150 km rupture length; 2.5 ka return time) have offset Holocene terraces (6, 12, 18, and 24 m characteristic slip)Block tectonics and triple junction kinematics account for 24 Ma deformation of west Tibet and rise of ≥8000 m‐high Karakorum range [ABSTRACT FROM AUTHOR]

Tectonic and surface processes (e.g., erosion) act in concert to denude and flatten elevated topography during and following collisional uplift. In orogens that collapsed rapidly (<10 Myr), the effectiveness and relative contribution of erosion remains poorly understood. Here, we use 1‐D and 2‐D finite‐difference models to test plausible magnitudes of erosion during denudation of the Scandian orogenic wedge, in northern Scotland, which previous work suggests may have been very rapid. Thermochronologic, stratigraphic, and thermobarometric data constrain initial post‐collision uplift rates as well as the cumulative post‐collisional exhumation magnitude. Using these constraints, we consider an idealized orogen subjected to fluvial incision, hillslope diffusion, and subsequent isostatic compensation for a duration of 10 Myr. Using a range of geomorphic parameters, we evaluate whether erosion alone is sufficient to achieve the observed cumulative exhumation. Additionally, we apply a thermal model during the same period to determine the viability of the previous erosion estimates in the presence of a transient geothermal gradient. For most cases with initial uplift rates of 0.5–2.5 mm yr−1, total erosion is insufficient to account for the observed Scandian denudation history, regardless of whether a fixed or transient geothermal gradient is assumed. Average elevations near the crest of the modeled orogen after 10 Myr are >1.4 km, which is inconsistent with the post‐Scandian landscape relief interpreted from the reconstructed depositional surface of the Emsian (407–403 Ma) Old Red Sandstone, Collectively these findings imply a combination of rapid erosion and tectonic denudation likely accomplished the rapid collapse of the Scandian wedge. Plain Language Summary: The destruction of mountain ranges is accomplished by numerous physical processes, which include erosion of the landscape and subsurface deformation of the Earth's crust. In mountains where this destruction occurred very rapidly, such as in northern Scotland, there is poor understanding of the relative effectiveness of each process in wearing mountains down. In this paper, we use computer models to calculate how much erosion might have occurred in the geologically short time frame after the mountains in Scotland stopped growing. These models track the effects of river erosion, hillslope movement, and crustal buoyancy on elevation change after mountain‐building has essentially ceased. We compare the model results to pressure‐temperature‐time data recorded in rocks exposed at the surface today that give us information about how fast the rocks were brought up to the Earth's surface from depth. Our inference based on these models is that erosion alone cannot remove material quickly enough to explain available geologic data, implying the importance of crustal thinning by deformation in the Scottish Highlands. Key Points: Published thermochronologic data for metamorphic rocks of the Scottish Highlands indicate rapid denudation following orogenesisThe models in this work suggest that denudation was not accomplished by surface processes alone, but required additional tectonic processesThis may indicate a role for channelized crustal flow similar to that proposed for the Himalaya and the East Greenland Caledonides [ABSTRACT FROM AUTHOR]

The Alpine Fault zone in New Zealand marks a major transpressional plate boundary that is late in its typical earthquake cycle. Understanding the subsurface structures is crucial to understand the tectonic processes taking place. A unique seismic survey including 2D lines, a 3D array, and borehole recordings, has been performed in the Whataroa Valley and provides new insights into the Alpine Fault zone down to ∼2 km depth at the location of the Deep Fault Drilling Project (DFDP)‐2 drill site. Seismic images are obtained by focusing prestack depth migration approaches. Despite the challenging conditions for seismic imaging within a sediment filled glacial valley and steeply dipping valley flanks, several structures related to the valley itself as well as the tectonic fault system are imaged. A set of several reflectors dipping 40°–56° to the southeast are identified in a ∼600 m wide zone that is interpreted to be the minimum extent of the damage zone. Different approaches image one distinct reflector dipping at ∼40°, which is interpreted to be the main Alpine Fault reflector located only ∼100 m beneath the maximum drilled depth of the DFDP‐2B borehole. At shallower depths (z < 0.5 km), additional reflectors are identified as fault segments with generally steeper dips up to 56°. Additionally, a glacially over‐deepened trough with nearly horizontally layered sediments and a major fault (z < 0.5 km) are identified 0.5–1 km south of the DFDP‐2B borehole. Thus, a complex structural environment is seismically imaged and shows the complexity of the Alpine Fault at Whataroa. Plain Language Summary: The Alpine Fault in New Zealand is a major plate boundary, where a large earthquake will likely occur in the near future. Thus, it is important to understanding the detailed processes of how and where such an earthquake occurs. Many scientists are involved in this work, particularly in the attempt of drilling through the fault zone with a ∼900 m deep borehole. We analyzed new seismic data from this area using sensors in the borehole and at the surface to record small ground movements caused by a vibrating surface source causing waves that travel through the ground. From these data, we obtained a detailed image of the structures in the subsurface, for the first time in 3D, by applying advanced analysis methods. Hence, we can better understand the shape of the glacial valley and of the fault zone, that is, the local structures of the continental plate boundary. We interpret at least 600 m wide zone of disturbed rocks and identify a potential major fractured plane down to about 1 km depth. Our studies may help to understand structures that host earthquakes in this area. Key Points: We use focusing prestack depth migration with detailed seismic data to analyze the complex subsurface environment of the Alpine Fault zoneSeismic images show Alpine Fault zone related reflectors at a depth of ∼0.2–1 km dipping ∼40°–56° around the DFDP‐2B boreholeComplex structures within the glacial Whataroa Valley are imaged showing steep valley flanks, faults, and internal sedimentary horizons [ABSTRACT FROM AUTHOR]

Subduction interface thermal structure changes drastically within the first few million years of underthrusting (i.e., subduction infancy). Metamorphic soles beneath ophiolites record snapshots of dynamic conditions and mechanical coupling during subduction infancy. Beneath the Samail Ophiolite (Oman), the sole comprises structurally higher high‐temperature (HT) and lower low‐temperature (LT) units. This inverted metamorphic gradient has been attributed to evolving metamorphic Pressure‐Temperature (P‐T) conditions during infancy; however, peak P‐T and timing of LT sole subduction are poorly constrained. Oman Drilling Project core BT‐1B sampled the base of the ophiolite in a location lacking the HT sole. Metasedimentary and meta‐mafic samples collected from 104 m of core reveal that the LT sole subducted to similar peak P as HT rocks preserved elsewhere in Oman, but experienced ∼300°C lower peak T. Prograde fabrics record Si‐in‐phengite and amphibole chemistries consistent with peak P‐T of ∼7–10 kbar and ∼450–550°C in the epidote‐amphibolite facies. Retrograde fabrics record a transition from near‐pervasive ductile to localized brittle strain under greenschist facies conditions. Titanite U‐Pb ages (n = 2) constrain timing of peak LT sole subduction to ∼91 Ma (post‐dating initial HT sole subduction by ∼12–13 Myr) and dynamic retrogression through ∼90 Ma. Combined with existing geo/thermo‐chronology, our results support a model of protracted subduction and accretion while the infant subduction zone experienced multi‐phase, slow‐fast‐slow cooling. Temporal overlap of HT sole cooling (rehydration?) and ophiolite formation suggests that cooling may lead to interface weakening, facilitating upper‐plate extension and spreading. The LT sole formed in a rapidly‐refrigerating forearc after ophiolite formation and may reflect the transition to self‐sustaining subduction. Plain Language Summary: Subduction zones continuously renew and recycle the surface of the Earth, influence global water and geochemical cycling, and generate a driving force for Plate Tectonics that is unique to our Earth. However, the mechanisms and tectonic conditions that allow subduction to initiate in the first place are poorly understood. Studies of metamorphic rocks from ancient subduction zones can provide insight into how pressure, temperature, metamorphic rock types, and water content change within tectonic plate boundaries. Using rocks from Oman that formed in an infant subduction zone, this study applies metamorphic petrology (quantitative measurements of mineral chemistry) and geochronology (timing of mineral growth) to constrain the changes in temperature through time spanning the first ∼10–15 million years of the subduction zone's lifetime. We synthesize new and pre‐existing data that together suggest the infant subduction zone experienced a multi‐phase cooling history, characterized by slow‐fast‐slow cooling. The first slow‐fast transition may represent a point in time where the infant subduction zone "turned on," that is, the transition from slow, forced convergence of two tectonic plates, to a faster‐moving, self‐sustaining, and plate‐boundary scale subduction zone. Key Points: The low‐temperature metamorphic sole beneath the Samail Ophiolite records subduction and return flow before juxtaposition with the ophioliteHigh sampling density of the 104 m‐thick core reveals it comprises three subunits that record continuous and stepwise changes in peak P‐TLow‐T sole rocks reached similar peak P as the high‐T sole but colder peak T (7–10 kbar, 500°C) and witnessed rapid interface refrigeration [ABSTRACT FROM AUTHOR]

The interconnection between anthropogenic and natural surface loads and seismicity continues to be poorly understood. The metropolitan Salt Lake City in Utah hosts various industrial, hydrological, and tectonic processes, including the Bingham Canyon mine and its associated tailings facility, precipitation and water storage at the surface and in aquifers, as well as the seismically active Wasatch Fault Zone. The March 18, 2020 M5.7 Magna earthquake occurred east of a mine tailings impoundment that receives ∼60 million tons/yr of ore waste products since the early 1900s. Here we investigate the spatiotemporal elastic stress changes due to anthropogenic mass transfer and natural hydrological loading and unloading. Two local earthquake clusters host persistent microseismicity and the 2020 M5.7 Magna earthquake sequence. The amplitude and sign of the computed Coulomb stress changes at seismogenic depths strongly vary with the receiver fault geometry, the frictional coefficient, and the location, and can reach tens of kPa and ∼1 kPa/yr due to the tailings loads, a substantial fraction of background tectonic loading. The long‐term and seasonal stress changes from regional hydrological processes are only up to a few kPa. A lack of statistically significant seasonality in seismicity across Utah suggests a weak control by cyclic hydrological loads. Explicit knowledge of the fault architecture is essential to allow for seismic hazard assessment considering external stress loading. Plain Language Summary: The anthropogenic surface modifications in naturally hazardous environments have received relatively little attention due to their small dimensions and shallow locations. We note a compelling spatial correlation between a mine tailings impoundment and the March 18, 2020 M5.7 Magna earthquake, its aftershocks, and persistent earthquake clusters in the Salt Lake City region. This highly populated region hosts various industrial, hydrological, and tectonic processes. Here we characterize the spatiotemporal stress changes since the early 1900s due to the industrial and hydrological sources. The modeled elastic stress changes in the three dimensional subsurface vary in sign and magnitude, depending on the location, geometry, and frictional properties of active faults. Comprehensive characterization of fault architecture and seismic monitoring near sites of industrial production is warranted in critical geological and tectonic settings to ensure socioeconomic health and sustainable development. Key Points: The M5.7 Magna earthquake and its aftershocks, as well as persistent historical seismicity occurred in two clustersThe elastic stresses near the hypocenter produced by nearby industrial loads exceed those from hydrological sources by two orders of magnitudeThe magnitude and sign of loading stresses resolved on receiver faults are sensitive to fault geometry, frictional coefficient, and location [ABSTRACT FROM AUTHOR]

The article discusses a study which examined the causes of the formation of normal faults at the Leh basin in the Northwest Himalaya. Topics covered results which showed that gravity tectonics is the cause of normal faults in the basin, the difference between the normal faults mapped within the intermontane basins with those that are tectonically driven, and the distribution of lithology, location of major Himalayan faults and the major fluvial streams.

Crustal deformation and seismic activity in the Levant is mainly related to the interplate Dead Sea Fault (DSF) and the intraplate Carmel–Gilboa Fault System (CGFS). In this study, we analyze the interseismic deformation along these fault systems using 23 years of Global Positioning System (GPS) measurements obtained from 209 campaign and 60 continuous stations. This GPS data set is the longest record and the densest data set for the DSF, the CGFS, and the Levant region. We use this data set to investigate the spatial variations of slip and creep rates along the southern and central sections of the DSF and the CGFS. Our inversion model results indicate that part of the tectonic motion is transferred from the DSF to the CGFS. We find that the left‐lateral strike‐slip motion along the DSF decreases in a rate of 0.9 ± 0.4 mm/year, from 4.8 ± 0.3 mm/year south to the intersection with the CGFS to 3.9 ± 0.4 mm/year north to this intersection. Along the CGFS, the left‐lateral strike‐slip motion ranges between ∼0.3 and 0.5 mm/year and the extension rate between ∼0.6 and 0.7 mm/year, indicating a total slip rate vector of 0.8 ± 0.4 mm/year in the DSF direction, in agreement with the reduction of slip rate along the DSF near the intersection with the CGFS. Shallow creep is found along the southern and central sections of the Dead Sea basin and the northern Jordan Valley section of the DSF, with creep rates of 3.4 ± 0.4 and 2.3 ± 0.4 mm/year, respectively. These creeping sections were identified as areas with thick Halite layers at the shallow subsurface. We suggest that shallow creep behavior along the DSF is govern by the presence and mechanical properties of the Halite, which probably allows plastic deformation and the transition to velocity strengthening at the shallow subsurface and promotes creep. Plain Language Summary: The variations in slip and creep rates along major faults and the distribution of strain rates are key factors in seismic hazard assessment. In this study, we address these factors for the Dead Sea Fault (DSF) and the Carmel–Gilboa Fault System (CGFS) using the longest record and the densest Global Positioning System (GPS) measurements for the Levant region. The DSF is the boundary between Arabia and Sinai tectonic plates, and the CGFS is a major intraplate fault system within the Sinai plate. We used 23 years of GPS measurements obtained from 269 stations. We find that the left‐lateral strike‐slip motion along the southern DSF is ∼5 mm/year and decreases to ∼4 mm/year north to the intersection with the CGFS. Along the CGFS, a total slip rate of ∼0.8 mm/year in the DSF direction is found. Shallow creep is found along the southern and central sections of the Dead Sea basin and the northern Jordan Valley section of the DSF. These creeping sections were identified as areas with thick salt layers at the shallow subsurface. We therefore suggest that the shallow creep along the DSF is due to the salt behavior, which can deform plastically and creep. Key Points: The interseismic deformation along the Dead Sea Fault (DSF) and the Carmel–Gilboa Fault System (CGFS) is analyzed using 23 years of dense Global Positioning System (GPS) measurementsA decrease in the slip rate along the DSF due to slip partitioning with the CGFS is found near the intersection of these faultsShallow creep is found along the southern and central sections of the Dead Sea basin and the northern Jordan Valley section of the DSF [ABSTRACT FROM AUTHOR]

Four large hydropower stations have recently been built downstream the Jinsha River in Southwestern China with a strong regional tectonic activity background. There is widely felt seismicity since the impoundment of the Xiluodu and Xiangjiaba reservoirs, increasing the public concern in this region. We begin with a criticality analysis of the faults near these reservoirs to quantify their susceptibility to triggered seismicity. Then we focus on the Xiluodu reservoir to investigate the correlation between the impoundment and seismicity nearby. We analyze the spatio‐temporal distribution of seismicity near the Xiluodu reservoir, and identify the plausible rapid and delayed seismic response due to the impoundment. According to the impoundment record, we explicitly model the hydro‐mechanical changes due to diffusion and reservoir water load, that is, pore pressure, elastic stress, and the resulting Coulomb stress. Our results show that the pore pressure changes can reach a level that may trigger fault reactivation and consequently, seismicity nearby. The water load can also induce the positive Coulomb stress changes on faults, depending on the fault orientation, which is especially important for understanding the earthquakes that occurred shortly after the impoundment and at more than 10 km distance from the reservoir. The combination of these two effects can induce positive Coulomb stress change over a larger area, which overlaps the majority of the events after the impoundment, including two M5+ events. While the causal relationship between the impoundment and seismicity warrants further analysis, we hope to inform the regional seismic impact of impoundment with this timely study. Plain Language Summary: There has been increasing concern over the construction of four hydropower stations situated along the Jinsha River, Southwestern China, due to the increased seismicity following the impoundment of Xiluodu and Xiangjiaba reservoirs. This calls for an in‐depth analysis of the temporal and spatial correlation between the increased seismicity and reservoir impoundment. In this study, we first quantify the relative criticality of the faults. The results suggest that the faults near the Wudongde and Baihetan hydropower stations are more likely to be reactivated and produce earthquakes. Then, we take the Xiluodu Reservoir as a timely example to analyze two possible mechanisms for increased seismicity, corresponding to the effect of the increased weight of reservoir water and the process of reservoir water pressure seepaging into the crust, respectively. We calculate the water pressure and stress changes due to the Xiluodu impoundment with numerical simulations. The results show that these two mechanisms can explain the occurrence of most earthquakes near the reservoir and nearby faults after the impoundment, including two M5+ events. Our study is important to understand the impact of reservoir impoundment on regional seismicity and its evolution, and to offer a scientific perspective for the long‐term operational decisions for these hydropower stations. Key Points: The plausible link between the Xiluodu reservoir impoundment and the increased seismicity is evidenced by spatio‐temporal correlationsThe pore pressure diffusion and reservoir water load can contribute to fault reactivation and earthquake triggering in the Xiluodu areaThe fault criticality analysis reveals that the NNW‐ and NS‐striking faults downstream the Jinsha River are more prone to reactivation [ABSTRACT FROM AUTHOR]

Monitoring vertical land motions (VLMs) at the level of 0.1 mm/yr remains one of the most challenging scientific applications of global navigation satellite systems (GNSS). Such small rates of change can result from climatic and tectonic phenomena, and their detection is important to many solid Earth‐related studies, including the prediction of coastal sea‐level change and the understanding of intraplate deformation. Reaching a level of precision allowing to detect such small signals requires a thorough understanding of the stochastic variability in GNSS VLM time series. This paper investigates how the aperiodic part of non‐tidal atmospheric and oceanic loading (NTAOL) deformations influences the stochastic properties of VLM time series. Using the time series of over 10,000 stations, we describe the impact of correcting for NTAOL deformation on 5 complementary metrics, namely: the repeatability of position residuals, the power‐spectrum of position residuals, the estimated time‐correlation properties, the corresponding velocity uncertainties, and the spatial correlation of the residuals. We show that NTAOL deformations cause a latitude‐dependent bias in white noise plus power‐law model parameter estimates. This bias is significantly mitigated when correcting for NTAOL deformation, which reduces velocity uncertainties at high latitudes by 70%. Therefore, removing NTAOL deformation before the statistical analysis of VLM time series might help to detect subtle VLM signals in these areas. Our spatial correlation analysis also reveals a seasonality in the spatial correlation of the residuals, which is reduced after removing NTAOL deformation, confirming that NTAOL is a clear source of common‐mode errors in GNSS VLM time series. Plain Language Summary: Monitoring vertical land motions (VLMs) at the level of 0.1 mm/yr remains one of the most challenging scientific applications of global navigation satellite systems (GNSS). Such small rates of change can result from climatic and tectonic phenomena, and their detection is important to the prediction of coastal sea‐level change and the understanding of deformation processes acting within tectonic plates. In this paper, we investigate to what extent accounting for the deformation of the Earth's crust due to changes in the distribution of the atmospheric and the oceanic pressure helps to detect small vertical ground deformation. By analyzing the data from over 10,000 globally distributed GNSS stations, we show that accounting for such atmospheric and oceanic deformation can reduce by 70% the uncertainty on the vertical velocity of GNSS stations at high latitudes, which could, for instance, improve sea‐level change monitoring in these areas. Key Points: Non‐tidal atmospheric and oceanic loading (NTAOL) deformations cause a latitudinal bias in parameter estimates of the white + power‐law noise model usually describing global navigation satellite systems (GNSS) time seriesRemoving NTAOL deformations corrects the latitudinal bias and dramatically reduces station velocity uncertainties at high latitudesNTAOL deformations also introduce a seasonal spatial correlation in GNSS vertical land motion time series [ABSTRACT FROM AUTHOR]

Tectonic research of the Tibetan Plateau has long focused on its deformation style and mechanisms. The 2008 Mw7.9 Wenchuan earthquake ruptured the Longmen Shan fault located at the eastern rim of the plateau and excited a viscoelastic response of the lithosphere. We infer a three‐dimensional (3D) rheological structure of eastern Tibet from modeling nine years of postseismic displacements observed by GPS. Our solution provides tight constraints on the lower‐crustal and upper‐mantle steady‐state viscosities of the Songpan‐Ganzi Terrane as (5.0 ± 0.7) × 1018 and (1.3 ± 0.3) × 1019 Pa s, respectively, consistent with a "jelly sandwich" model of Tibet, but not with some crustal channel flow models featuring much lower viscosities. The inferred lower‐crustal and upper‐mantle transient viscosities are (5.0 ± 1.3) × 1017 and (5.0 ± 1.5) × 1018 Pa s, respectively, suggesting nonlinear deformation mechanisms. The adjacent West Qinling and Sichuan blocks feature an order‐of‐magnitude higher rheological strength, which is consistent with the changes in the crustal material properties and interseismic deformation style across the East Kunlun‐Tazang and Longmen Shan faults. Our results enable us to propose a conceptual 3D tectonic deformation model, in which the eastward extrusion of Tibet is absorbed in the Songpan‐Ganzi crust mainly by E‐W shortening and N‐S extension, accommodated through faulting of conjugate strike‐slip faults in the upper crust and distributed shear in the lower crust. Plain Language Summary: One of the fundamental questions in Earth science is the deformation mechanism of the continents, which controls the topography of the land we live on, the distribution of the resources extracted to support our living, and the origins of natural hazards such as landslides and earthquakes. The Tibetan Plateau, arguably, is the best natural laboratory to study the deformation mechanism of the continents. In this study, we address two critically important and much debated problems in Tibetan Plateau dynamics; that is, the rheologic structure of the Tibetan lithosphere and how it deforms under tectonic loading. We use nine years of mostly unpublished three‐dimensional (3D) deformation data collected in the aftermath of the 2008 Mw7.9 Wenchuan earthquake to infer the rheological structure of the eastern Tibet lithosphere. Our results are consistent with a "jelly sandwich" model, with a relatively weak lower crust underlain by a stronger upper mantle. However, they do not support the very low viscosities envisioned by some of the channel flow models of lower crustal deformation in eastern Tibet. We also propose a conceptual 3D tectonic deformation model, in which the eastward extrusion of Tibet is absorbed in the Songpan‐Ganzi crust by E‐W shortening and N‐S extension, accommodated through conjugate faults in the upper crust and distributed shear in the lower crust. Key Points: A comprehensive GPS data set is provided to cover nine years of three‐dimensional (3D) postseismic displacements after the 2008 Wenchuan earthquakeGPS constrained eastern Tibet Lithospheric rheological structure agrees with a "jelly sandwich" model, not models of much lower viscositiesA conceptual 3D tectonic deformation model in eastern Tibet is proposed to characterize its dynamic deformation style and mechanisms [ABSTRACT FROM AUTHOR]

When plate tectonics emerged on Earth is one of the most fundamental questions in geosciences. Nowadays, different arguments from diverse research fields (petrology, structural geology, geochemical and numerical modeling) postulate that the lithospheric subduction began sometime in the Archean-Paleoproterozoic with different styles. This study provides robust petrologic evidence for the modern-style plate tectonics onset in the Paleoproterozoic featured by low geothermal gradients. We investigated the Salma eclogite association from the Precambrian Belomorian Province (BP) on the Fennoscandian Shield (Russia). Based on the garnet chemical annuli (major and trace elements) and therein mineral inclusions, plus comprehensive zircon isotopic-chemical analyses, we establish the prograde metamorphic history of the eclogite, leading to peak conditions of 2.2-2.3 GPa, 650-670 °C prior to 1.93 Ga. We thus, for the first time, conclude cold subduction (303 ± 16 °C/GPa) proceeded in the BP, connected with the Lapland-Kola Orogen (LKO). Such conclusions are clearly against the previously argued Archean subduction scenario and "warm" tectonic setting in the BP, and are very important for understanding the geodynamics of the early Earth. Furthermore, in the light of other scarce coeval "cold" Paleoproterozoic high pressure (HP) metamorphic rocks elsewhere, we posit that modern-style plate tectonics already operated in the form of the Columbia Supercontinent. • The Precambrian Belomorian eclogite preserves prograde metamorphic imprints and records low T/P thermal gradient. • The cold Belomorian eclogite was formed 1.9 billion years ago during oceanic subduction. • The previously argued Archean eclogitization and warm subduction are highly unlikely. • Modern-style plate tectonics onset in the form of the Columbia supercontinent is advocated. [ABSTRACT FROM AUTHOR]

The article presents the discussion on sedimentary petrography providing a key unravelling exogenic cycling and learning about fundamental processes shaping the Earth fuelling a wealth of recent research and sedimentary provenance analysis.

The Bradano Basin is a foreland basin along the Africa/Eurasia plate boundary. Due to its location and physiography, between Southern Apennines (SA) and Calabrian Arc (CA), it represents a natural recorder of Plio-Pleistocene tectonic processes. Integrated analysis of seismic reflection data, exploration well logs and seafloor bathymetry allowed us to unravel the basin architecture and the interplay between tectonics and sedimentation, providing stratigraphic and structural evidences on deep processes and shallow morpho-structural development. It results, that the post-Messinian tectonic evolution on this area is marked by two major tectonic events, whose effects are recorded in four sedimentary sequences bounded by interregional unconformities. During Pliocene times, an obliquely convergent margin led to collision between SA and CA, associated with shelf to deep marine turbiditic deposits. Around the Pliocene-Pleistocene boundary (2.58 Ma), a sudden and widespread rearrangement took place. The SA front, along with portions of the earlier obliquely collisional margin, started to move toward the NE, along progressively deeper detachments involving the lower Apulia plate. During this phase, a fast (3.8–8.3 cm/yr) ~50 km translation of the orogenic wedge was followed by uplift and slow-rate shortening (1.9 mm/year), associated with seafloor folding. This second phase is marked by deep marine deposits in the central part of the basin, and clinoforms in shallower western and northern sectors. Our data suggest that no oceanic crust is presently subducting below the Bradano Basin, although we cannot exclude that a narrow sliver of oceanic lithosphere was subducted before and/or during Pliocene times. The complex deformation pattern observed, represents the response to the interaction of (small-) plates, which is still active and important to be considered in neotectonics and paleoseismological reconstructions. • The Bradano Basin (BB) is a key area for the post-Messinian tectono-stratigraphic evolution of the Ionian Sea. • The post-Messinian BB preserves three major interregional unconformities likely coeval in the whole central Mediterranean Sea. • The interregional unconformities trace the sudden shift from oblique convergence/collision to orogen translation. • The present day BB lithospheric setting dates back to the early Pleistocene when no oceanic lithosphere was present. • This deep plates' reorganization calls for cautions in older plate tectonic reconstructions of the central Mediterranean Sea. • The present day BB setting should be taken into account for neotectonics and paleo-seismological reconstructions. [ABSTRACT FROM AUTHOR]