Earthquake magnitude is critical for both seismic and tsunami hazard assessments, as well as early warning. However, because modern seismological observations are limited in duration, the magnitudes of many past events were not recorded or are poorly constrained over hundreds and/or thousands of years of the earthquake cycle. This gap limits our understanding of long-term seismicity and hampers effective hazard mitigation. Here, we propose a novel approach to estimate earthquake magnitude using fault zone scarp area. Theoretical considerations suggest that coseismic scarp area scales with moment magnitude (Mw) according to a and blind faults. For near-surface faults, this relationship is calibrated using a global dataset of 16 modern earthquakes and six paleoearthquakes, including events on highangle normal faults and low-angle thrusts, and provides a good fit to the global dataset. For blind fault structures, the relationship is validated by comparing pre- and postearthquake surface deformation associated with the 2011 Tohoku-oki earthquake along blind fault structure in the coastal zone of shallow seismic-reflection data collected offarea can be measured, both on land and off shore, enabling the extension of earthquake catalogs beyond the limits of modern records. By filling gaps in seismic records, this method improves seismic and tsunami hazard assessments, refines recurrence rates and worstcase scenarios, and supports more effective preparedness and mitigation.

The southeastern margin of the Tibetan Plateau lies within the oblique convergence zone of the India-Eurasia collision. Since the Cenozoic, this region has experienced intense crust-mantle interactions, active tectono-magmatic processes, and complex focal mechanisms, reflecting a crustal structure with pronounced vertical layering and lateral segmentation. To better understand the regional stress regime and fault activity, we compiled a comprehensive database of focal mechanism solutions for the southeastern Tibetan Plateau. We collected and integrated earthquake data from 1950 to 2023 across the Sichuan-Yunnan region and adjacent areas. After data cleaning and integration, a database of 9902 high-quality focal mechanism solutions was established. Using a damped stress inversion method, we derived regional stress field models on 1°×1° and 0.2°×0.2° grids. The results reveal that: (1) focal mechanism types exhibit significant spatial heterogeneity; strike-slip events dominate the region, thrust events concentrate along the Longmenshan fault zone, and normal faulting prevails along the western boundary of the Sichuan-Yunnan block. (2) The large-scale stress field shows a systematic clockwise rotation of the maximum compressive stress axis (σ1) from north to south, consistent with the far-field effect of the ongoing India-Eurasia collision. (3) The high-resolution results reveal multi-scale stress variations, with strong horizontal continuity of σ1 across the plateau, supporting a long-term stable compressional regime. In contrast, higher three-dimensional complexity occurs along the block boundaries and southern Yunnan, particularly across the Lijiang-Xiaojinhe fault, where a clear north-south stress gradient is observed. This study provides the first systematic stress field characterization based on a unified focal mechanism database for the southeastern Tibetan Plateau, offering refined constraints on crustal deformation and insights into the geodynamic processes governing continental earthquake generation.

[Objective]The Tianshan is an intracontinental orogenic belt reactivated in the Cenozoic by far-field effects of the India-Asia collision.Its Cenozoic tectonic evolution is thus key to understanding intracontinental deformation mechanisms.[Methods]Based on stratigraphic sedimentary characteristics and provenance tracing of a section on the northern margin of the Turpan Basin(south of the Bogda Shan),the Late Cretaceous to Cenozoic tectonic and geomorphic evolution of the East Tianshan and its adjacent region has been constrained.[Results]Field investigations reveal that the Paleocene and lower Oligocene strata in this area consist predominantly of red mudstones,indicating a lacustrine environment and stable tectonic conditions.The uppermost Cretaceous and Eocene strata contain relatively thin conglomerate deposits with small clast diameters,suggesting slight tectonic uplift of the Bogda Shan.In contrast,the upper Oligocene to Pliocene strata are composed of extremely thick,coarse conglomerates,reflecting long-term and intense tectonic activity.Detrital zircon U-Pb ages show that,from the Late Cretaceous to the Oligocene,the northern Turpan Basin continuously received detrital material from the West Tianshan,implying low topographic relief of the Bogda Shan during this period.Since the Miocene,however,the Bogda Shan has become the primary sediment source,indicating its rapid tectonic uplift.[Conclusions]In summary,the Bogda Shan remained tectonically stable with low relief during the Late Cretaceous to Oligocene.Since the late Oligocene,it has undergone intense deformation and rapid uplift,becoming the sole provenance area for the northern Turpan Basin.[Significance]This study refines the Cenozoic tectono-geomorphic evolution of the East Tianshan,thereby contributing to a better understanding of the intracontinental deformation processes resulting from the India-Asia collision.

The southeastern Tibetan Plateau represents a critical transition zone between the high plateau interior and the surrounding region with moderate elevation. Its topographic uplift history provides key constraints on the geodynamic mechanisms driving plateau growth, serving as an ideal natural laboratory for exploring the coupled effects of tectonics, monsoon dynamics, and biodiversity. However, the spatiotemporal patterns of regional uplift across distinct tectonic domains remain debated, primarily due to the limited resolution and accuracy of existing geochronological and paleo-elevation proxies. To resolve these uncertainties, we synthesize sedimentary archives from 16 Cenozoic basins across the southeastern plateau. We integrate high-resolution paleoelevation proxies, including stable and clumped isotopes, with multi-proxy paleoclimate records derived from palynological assemblages and leaf physiognomy. This multi-basin comparison reveals that the southeastern Tibetan Plateau experienced a major phase of regional uplift during the Late Eocene to Early Oligocene, characterized by a systematic decrease in uplift magnitude from the plateau interior toward the outer margins. A second phase of localized uplift occurred along the southeastern margin during the Middle to Late Miocene, progressively establishing the modern topographic configuration. Throughout the Cenozoic, this surface uplift was accompanied by distinct stages of climatic evolution. The region was predominantly arid during the Early Eocene, followed by a transition toward more humid conditions in the Late Eocene that persisted throughout the Late Oligocene. From the Middle to Late Miocene onward, the southeastern margin generally experienced a warm and humid subtropical climate, with regional variability reflecting the episodic reorganization and strengthening of the monsoon system. During the Pliocene, intensified global cooling and the expansion of Northern Hemisphere glaciation drove a shift toward cooler climatic conditions across the southeastern Tibetan Plateau. These findings clarify the spatiotemporal uplift history of the southeastern plateau margin and highlight its fundamental role in regional climate reorganization.

The persistence of mountainous topography in tectonically quiescent settings remains one of the outstanding questions in geomorphology. Along the northern passive continental margin of the South China Sea (SCS), although topography is expected to be entirely eroded under a theoretical relief-decay threshold of ca 1 cm/kyr, mountainous terrain has persisted since the Oligocene without significant tectonic uplift. This long-term persistence of topography is attributed either to the preservation of relict features under subdued erosion rates or to a dynamic equilibrium between rock uplift and spatially variable erosion. Distinguishing between these two scenarios remains difficult due to a lack of multi-domains erosion rate constraints across the mountainous interior. In this study, we address this issue by utilizing four in-situ cosmogenic 10Be depth profiles to quantify erosion rates across representative geomorphic domains along the northern coast of the SCS, specifically flat-top surfaces, bare-rock and regolith-mantled hillslopes, and pediment platforms. We evaluate three numerical inversion models, including steady-state erosion, continuous exposure, and abrupt mass loss, using chisquare statistics, solution stability, and field observations. The optimal solutions show that erosion rates exceed the relief-decay threshold on regolith-mantled hillslopes (ca. 8.12 cm/kyr) and pediment platforms (ca. 3.38 cm/ kyr), match the threshold on flat-top surfaces (ca. 1.1 cm/kyr) and fall below it on bare-rock hillslopes (ca. 0.73 cm/kyr). These results demonstrate that erosion rates across the geomorphic domains exhibit pronounced spatial variability, with the majority of these geomorphic domains actively eroding at rates above the theoretical reliefdecay threshold. The above-threshold erosion, combined with the order-of-magnitude convergence among catchment-wide erosion rates, thermochronology-based erosion rates, and theoretical isostatic rock uplift rates, demonstrates that a dynamic equilibrium between rock uplift and spatially variable erosion is more likely to drive the long-term persistence of mountainous topography along the northern passive continental margin of the SCS.

[Objective]Tectonic vergence records the geometric asymmetry and kinematic directionality of shortening during orogenic thickening and provides a key link between surface deformation and lithospheric-scale geodynamics.Although vergence is widely used in structural geology,its expression at the scale of entire orogenic belts remains insufficiently clarified,especially in intracontinental settings where stable plate-boundary subduction is absent.This study aims to compare vergence patterns from plate-margin orogens to intracontinental mountain belts and to identify the mechanisms controlling their formation,maintenance,weakening,and transformation.[Methods]We synthesize five representative orogenic systems:the Central Andes,Taiwan,the Alps,the Qilian Shan,and the Tian Shan.Surface structural styles,fold-thrust belt geometry,orogen-foreland basin coupling,geomorphic evolution,modern crustal deformation,seismicity,and lithospheric architecture—constrained by Moho/LAB geometry and geophysical imaging—are integrated to evaluate vergence at multiple scales.[Results]Plate-margin convergent systems commonly develop stable one-sided tectonic vergence.In the Central Andes,long-lived subduction of the Nazca slab provides persistent asymmetric forcing,causing shortening to be localized above the subduction interface and transmitted eastward toward the retroarc and foreland.The Altiplano Plateau,with crustal thickness locally reaching 60-75 km,records progressive Cenozoic crustal thickening,uplift,and eastward propagation of deformation.Taiwan,as a young arc-continent collision system,locally records early-stage bidirectional deformation around the Central Range and arc-side backthrusting near the Longitudinal Valley-Coastal Range system.However,foreland basin evolution,westward migration of the frontal fold-thrust belt,and modern shortening concentrated along the western Taiwan thrust system indicate that its long-term,orogen-scale,dominant vergence remains west-directed.The Alps demonstrate that tectonic vergence is time-dependent.During early subduction and continental collision,deformation was localized along a single subduction interface,producing a north-vergent simple-shear-dominated architecture.After collision,slab break-off,eclogitization of the orogenic root,and thermomechanical reorganization weakened the earlier interface-controlled deformation and promoted strain redistribution across both flanks of the orogen,leading to paired north-and south-vergent thrust systems and a more symmetric collisional structure.In intracontinental orogens,stable one-sided vergence is not guaranteed.The Qilian Shan and Tian Shan lack compelling evidence for a continuous,long-lived,single-sided lithospheric subduction interface.Their deformation is mainly expressed by distributed crustal thickening,high-angle reverse faulting on opposing flanks,and near-symmetric shortening.Recent studies from the Qilian Shan further show that lithospheric-scale tectonic wedges may develop along basin-mountain transition zones,where relatively rigid basin lithosphere wedges into the weakened lower crust of a thickened orogen.Such wedge structures are best interpreted as local expressions within a pure-shear,vertically coherent deformation framework rather than as large-scale simple-shear intracontinental subduction.[Conclusions]Lithospheric-scale tectonic vergence is controlled by the coupling among boundary conditions,negative-buoyancy forcing,and lithospheric strength-buoyancy structure.Persistent single-sided slabs or effective negative-buoyancy sources favor stable simple-shear vergence,whereas slab break-off,loss of one-sided forcing,and mechanically strong opposing blocks favor distributed pure-shear thickening and weak or near-symmetric vergence.[Significance]This study provides a unified framework for interpreting tectonic vergence from plate margins to continental interiors.It highlights vergence as a geometrically testable indicator for linking surface deformation,basin-orogen coupling,and lithospheric-scale geodynamic processes.

Structural wedges, defined as contractional structures comprising kinematically linked forethrust and backthrust, represent a fundamental structural element in fold-and-thrust belts. Synchronous displacement on both thrust faults drives the wedge into the surrounding rocks, creating distinctive uplift and folding patterns. While previous 2D analyses have established their kinematic configurations, resolving their 3D growth patterns remains challenging. In this study, we identify a WNW-trending structural wedge beneath the Yingjisha (YJS) anticline in the West Kunlun piedmont, and characterize its 3D growth pattern through high-resolution 2D seismic reflection profiles, geometric and kinematic analyses, and 3D structural model. Structural forward modeling and quantitative analysis of fault slip reveal the synchronous slip on the forethrust and backthrust, demonstrating that the YJS anticline is controlled by a structural wedge. The ages of growth strata document a progression from 1.26 +/- 0.11 Ma in the core to 0.85 +/- 0.11 Ma in the eastern plunging termination, indicating lateral growth of the YJS anticline, with an eastward lateral growth rate of 35-84 km/Ma. Furthermore, through 3D structural model, we discover the consistency of the fault geometry along the strike. Two other natural structural wedges (Kashi and Dafengshan anticlines) validate this discovery, suggesting that undeformed segments inherit fault geometry from adjacent deformed segments along the strike, which may represent a common characteristic of structural wedges dominated by lateral growth. Our results not only establish a framework for understanding the 3D lateral growth of structural wedges, but also provide new insights into the formation and evolution of fold-and-thrust belts worldwide.

Undisturbed marine soft clay from Daya Bay in Shenzhen poses severe geotechnical challenges owing to its high sensitivity and low shear strength. In this study, the microstructural evolution and underlying mechanical mechanisms of this soft clay under one-dimensional consolidation were systematically investigated. A multi-scale analytical approach was adopted, integrating Mercury Intrusion Porosimetry (MIP), dual-energy synchrotron X-ray Micro-Computed Tomography (Micro-CT) with phase recovery technology, and Discrete Element Method (DEM) simulations implemented in PFC3D 6.0. The results show that one-dimensional consolidation induces a distinct structural transition of the clay’s pore size distribution from bimodal to unimodal, with the connectivity of macropores being completely destroyed under high consolidation pressure. Two structural yield stresses were identified at 62 kPa and 676 kPa, corresponding to the structural failure of inter-cluster aggregates and intra-cluster particles, respectively, which characterizes the mechanical transformation of the clay from aggregate rearrangement to intra-aggregate compression. Numerical simulation results further demonstrate that the increase in consolidation pressure leads to a gradual rise in the particle coordination number and a significant decrease in the contact-sliding ratio, thereby enhancing the structural stability of the clay skeleton. These findings establish a quantitative correlation between the microscopic pore structure reorganization and macroscopic mechanical response of soft clay, and provide a robust mechanistic basis for accurate settlement prediction and ground improvement design in coastal geotechnical engineering.

The Indochina block is one of the major blocks separating the northern and southern branches of the east Paleo-Tethys Ocean. Paleomagnetic studies on the late Paleozoic drift history of the Indochina block are crucial for quantitatively constraining the evolution of the east Paleo-Tethys Ocean. In this study, we conducted paleomagnetic analyses on the Wusu basalts in the Simao Basin (southwestern Yunnan Province, China), located in the northern part of the Indochina block. Paleomagnetic analysis of the Wusu basalts reveals a clockwise rotation in remanent magnetization directions. We interpret this observed rotational pattern as the tectonic result of bookshelf faulting within a dextral intra-arc shear zone, which was active during the oblique subduction of the east Paleo-Tethys Ocean. Paleomagnetic analysis passed an inclination-only fold test, indicating a paleolatitude of 14.2 degrees S +/- 3.2 degrees for the sampling area (23.3 degrees N, 101.6 degrees E) during the Early Permian (287 +/- 5 Ma). This new paleolatitude, combined with existing data, confirms a three-phase drift history for the Indochina and North Qiangtang blocks. They initially drifted northward slowly from the Late Carboniferous to the Early Permian, then remained relatively stable during the Early to Middle Permian, and underwent accelerated northward drift after the Middle Permian. Based on paleomagnetic analyses and regional magmatic records, we propose that the opposing subduction of the southern and northern branches of the east Paleo-Tethys Ocean during the Early to Middle Permian may have contributed to this period of relative stability.

The Qilian Shan is one of the most active and youngest intraplate orogenic belts in the Tibetan Plateau, its formation and uplift mechanisms can provide critical constraints for understanding the recent evolution of the plateau. However, the detailed uplift of the Qilian Shan remains debated. In this study, we deployed a 640 km long profile with short-period seismometers spacing of 1 km across the eastern Qilian Shan, and delineated the high-resolution crustal interfaces and velocity structures with receiver functions and joint inversion methods. The results reveal that the Moho along the entire profile continuously varies without any obvious offset. Combined with the high-angle fault contact between the basin and mountain constrained by surface geology and microseismic localization, we propose that the uplift of the eastern Qilian Shan is mainly characterized by pure shear deformation, rather than the simple shear deformation that might be induced by the subduction of the Asian lithosphere. Crustal thickening in the eastern Qilian Shan shows different segmentation characteristics: the lower crust is dominantly thickened in the North and South Qilian, while the upper crust is thickened in the Central Qilian. A weak layer at the base of the upper crust mediates the differential crustal thickening. The total shortening in the upper crust is approximately equivalent to that in the lower crust across the eastern Qilian Shan. Therefore, from the perspective of the entire orogenic belt, the crustal deformation is incomplete mechanical decoupling and remains a continuous deformation model.

Three strong aftershocks (M(S)6+) occurred in the northeastern rupture zone of the 2008 M(W)7.9 Wenchuan earthquake within three months. No surface ruptures were observed, and the seismogenic faults remain unclear. Resolving the source parameters and seismogenic structures of these strong aftershocks is essential for clarifying the rupture termination mechanism of the mainshock and for future seismic hazard assessment. In this study, we determined the point source parameters of eight moderate to strong aftershocks and the rupture directivity of three strong aftershocks through regional and teleseismic waveform modeling. The focal mechanisms of these aftershocks are diverse, including both strike-slip and thrust-slip types, with centroid depths ranging from the middle crust (12-19 km) to the shallow part (3-5 km), highlighting the complexity in the rupture termination zone. The rupture directivity analysis shows that the strike-slip May 25 event (Mw6.0) ruptured from SW to NE along the right-lateral plane (60 degrees/81 degrees/173 degrees) for similar to 7 km, the strike-slip July 24 event (Mw5.5) on ruptured from NNE to SSW along the right-lateral plane (16 degrees/67 degrees/147 degrees) for similar to 6 km, and the thrust-slip August 5 event (Mw5.9) ruptured upwards along the northeast dipping plane (339 degrees/56 degrees/83 degrees) for 6-8 km. The strike of ruptured faults changes from NE to NNE, differing from the Qingchuan fault. The estimated stress drop of the event in the middle crust (similar to 19 km, 9.3 MPa) is larger than that of the shallower event (similar to 4 km, 1.9 MPa), possibly due to the low strength of the shallow crust. Moreover, the rupture direction of the July 24 event is opposite to that of the mainshock, potentially due to the Bikou block's differing bi-material contrast, which may have hindered the northeastward extension of the mainshock's rupture.

The ongoing India-Asia convergence during the Cenozoic drove intensively compressional deformation in the northern margins of the Tibetan Plateau, such as Tianshan, which formed the highest mountain peaks and lowest intermontane basins in the Central Asia. Understanding the spatial-temporal evolution of the Tianshan and its marginal fold-thrust belts (FTB) are crucial for interpreting intracontinental deformation processes related to the India-Asia collision. In this work, low-temperature thermochronology data and growth strata analysis are integrated to constrain chronologically the onset of deformation of the structures in FTB (Belt I, II, and the Huoyanshan Anticline) along the southern front of the Chinese East Tianshan (CETS), and then to underpin the Cenozoic deformational model of the CETS. We propose a three-stage expansion model to reveal the processes by which the southern thrust belts in the CETS have extended into the Turpan Basin since the Oligocene. Stage 1: thrusting of the South Bogda Fault since similar to 30 Ma, which caused the initial uplift of the CETS; Stage 2: deformation expanded southward to the Tarlang River region at similar to 20 Ma; Stage 3: the thrust belts propagated southward in a thin-skinned structural style to the Huoyanshan Anticline in the central part of the Turpan Basin since similar to 10 Ma. The progressive propagation of FTB in the southern piedmont of the CETS could have responded to multi-stage uplift of the Tibetan Plateau during the Cenozoic.

Eurasian drylands constitute the largest contiguous arid and semi-arid region globally, where the ecosystems are particularly vulnerable to environmental changes and anthropogenic activities, posing threats to the sustainability of the regional vegetation. Therefore, quantifying vegetation dynamics and identifying their driving factors is crucial in environmental management and regulation. In this study, we evaluated the spatio-temporal dynamics of vegetation and their underlying drivers across Eurasian drylands during 2003-2020. The results show that the satellite-derived leaf area index (LAI) and gross primary production (GPP) exhibited consistently significant increasing trends. Conversely, soil moisture and terrestrial water storage declined over the same period, while significant increasing trends were found in temperature and vapor pressure deficit. Precipitation and surface net solar radiation showed non-significant increasing trends. Attribution analysis show that, irrespective of CO2 fertilization effect, both environmental factors and anthropogenic activities contributed positively to vegetation greening, with anthropogenic activities playing the dominant role. Among the environmental drivers, water availability was identified as the most influential factor, accounting for over 50 % of the increase in vegetation greening. The reported overwhelming anthropogenic effect on regional vegetation greening, despite regional drying trend, raises concerns about the long-term sustainability of these ecosystems under future climate change. Therefore, close monitoring and early alerts regarding vegetation growth are imperative for the sustainable management of Eurasian dryland ecosystems.

Waterfalls are steep steps in river sections that longitudinally break river channels, typically found in drainage systems with tectonically active conditions. However, large waterfalls can also form in tectonically inactive areas, creating a phenomenon that is not yet fully understood. The Hukou Waterfall, located in the Jinshaan Gorge of the Yellow River, an area generally considered tectonically stable, preserves datable landforms and provides an opportunity to study the formation and propagation processes of waterfalls. In this study, we reconstruct the paleochannel associated with the recession of the Hukou Waterfall by correlating fluvial terraces and paleo-outlets. Our results suggest that the waterfall once existed at a paleo base level approximately 65 m higher than its current position. The migration rates of the waterfall varied between 16.9 and 30.3 cm/a during its recession, with faster recession during inter-glacial periods. Based on these findings, we estimate that the Hukou Waterfall entered the Jinshaan Gorge between 233.5 and 260.0 ka, and propose that the Hukou Waterfall originated from a sudden drop in base level due to drainage integration between the Fenwei Basin and the Sanmen Gorge. Our analysis also shows that migration rates, as well as overburden on waterfall-related terraces, correlate with cyclic climate patterns, highlighting the role of climate variability in driving waterfall migration over time. These findings may help refine models of river incision, base-level change, and knickpoint migration, contributing to the broader understanding of waterfall migration patterns in response to both climate and tectonic changes and offering a template for studying landform evolution in other river systems worldwide.

The intense seismicity observed across East Asia, particularly in the southeastern Tibetan Plateau, cannot be adequately explained by classical plate tectonics. Instead, the concept of active block tectonics-viewing the continental lithosphere as a mosaic of deformable yet kinematically independent blocks bounded by active faults-provided new insights into the intracontinental deformation. In this study, we integrate active tectonic, seismological, and geophysical data sets to delineate a hierarchical system of first- to fourth-order active block tectonics models in the southeastern Tibetan Plateau. Block rotations and internal strain rates are quantified using the TDEFNODE modeling framework applied to GNSS velocity data. The results reveal that present-day deformation is partitioned among multiple blocks and accommodated through both rigid block rotation and distributed internal strain, reflecting strong lithospheric heterogeneity and mechanical segmentation. Based on these observations, we propose updated criteria for delineating active blocks in continental interiors. Our findings provide new insights into the late-stage evolution of orogenic systems and establish a seismologically validated, geophysically constrained framework for interpreting intracontinental deformation and assessing seismic hazards in the southeastern Tibetan Plateau.

The orogenic processes along the northeastern margin of the Tibetan Plateau are often regarded as critical evidence of the ongoing Cenozoic collision between the Indian and Asian plates, driving the plateau's progressive northward expansion. However, the mechanisms driving uplift in the Qilian Shan since the mid-Miocene remain poorly constrained due to limited record directly linking mountain building. Here, we present new stratigraphic and fault activity observations from the fold-and-thrust belt along the northern margin of the Qaidam Basin, providing insights into the tectonic context of basin-mountain development. By integrating high-resolution magnetostratigraphic data, deep seismic imaging, and field observations from the fold-and-thrust belt, we reconstruct a comprehensive history of sedimentation and tectonic activity from 13.5 Ma to 0.5 Ma. Our findings indicate that shifts in paleocurrents/provenance are concurrent with variations in sedimentation rates and stratigraphic tilting (growth strata) due to fault-propagation-folding. These observations suggest that the southern Qilian Shan underwent three distinct phases of accelerated uplift and southward expansion during similar to 13.5-10 Ma, similar to 6-5 Ma, and similar to 3.5-2 Ma. Synthesizing these results with prior studies on the timing of deformation, we propose that since the mid-Miocene, the Qilian Shan have expanded simultaneously in opposite directions along both their northern and southern margins, with eastward growth. This expansion pattern coupled with crustal-scale pure shear deformation, suggests that gravitational collapse triggered by ongoing internal uplift of the Tibetan Plateau, diffusing outward toward the plateau's margins, may be a key driver of the horizontal compressive stresses along the northeastern Tibetan Plateau.

Syn-tectonic deposition of sediments (growth strata) preserves a direct record of mountain building-erosion and basin deformation. When and how these sediments incorporated into forward propagating fold-and-thrust (FTB) belts can shed light on the above processes. Despite many years of research, there is still ongoing debate about the timing and mechanisms of the southern Qaidam fold-and-thrust belt in the northeastern Tibetan Plateau. Here, we provide insight into the deformation of the Qaidam Basin and the broader tectonic processes of the northeastern Tibetan Plateau through detailed analysis of the Dafengshan (DFS), Jiandingshan (JDS) and Heiliangzi (HLZ) anticlines along the southern Qaidam FTB. Identification of the growth strata by Area-Depth analysis and age determination indicate that deformation of the DFS anticline initiated in the mid-Miocene (∼15 Ma), and has successively experienced lateral growth (∼15-8.0 Ma) and uplift (∼8.0 Ma-present). This timeline of deformation coincides with periods of mountain building in the northeastern Tibetan Plateau and might be related to the removal of mantle beneath northern Tibet. The synchronization of growth strata with an increase in sedimentation and exhumation rates reveals the reactivation of the tectonic belt around the basin in the mid-Miocene, creating the current basin-range landform; since ∼8 Ma, compression has expanded rapidly into the interior of the Qaidam Basin, leading to incorporation of basin deposits into the FTB. Geomorphological analyses coupled with 3-D fold modeling demonstrate that the JDS and HLZ-fold train with S-shaped configuration is a coherent fold system developed by lateral growth and linkage of two different fold segments in the context of the N-S directional compression of the plateau. Considering the prevalent S-shaped constructions within the basin and the current seismicity, we propose that the dominant structures in the southwestern Qaidam Basin are a series of thrust faults and folds controlled by the compression component of the East Kunlun Fault, with a limited influence from the Altyn Tagh Fault.

Figure S1: Elevation and geophysical data map. Figure S2: Fault slip rates in the West Qinling Syntaxis and its adjacent region. Figure S3: Comparison of the observed and modeled GPS velocities within the West Qinling Belt. Figure S4: The distribution of seismic stations. Figure S5: The fitting curve of travel time and epicentral distance. Figure S6: Distribution of ray paths. Figure S7: Trade-off curves for smoothing and damping. Figure S8: The result of checkerboard resolution test. Figure S9: Deep P-wave velocity structure transect. Figure S10: Distribution of epicenters after relocation. Supplemental Text S1: Technical details of the tomography method and inversion.

Continental rejuvenation results from the tectonic reactivation of crustal structures and lithospheric reworking by mantle flow. Geochemical observations and field mapping have traditionally provided the primary evidence for the secular evolution of crustal composition and tectonic processes during continental rejuvenation. Nonetheless, the impact of continental rejuvenation on the observed present-day strain rate and orogenic-scale lithospheric structure has not been well constrained. The pre-existing E-W−trending Central China Orogenic Belt has been overprinted by the N-S−trending Central Longitudinal Seismic Belt and constitutes the intracontinental West Qinling Syntaxis in central China, where the tectonic setting changes eastward from contraction to extension. Combining updated global positioning system data and high-resolution crustal seismic tomography, we reveal a modern continental rejuvenation process within the West Qinling Syntaxis in central China. The northward extrusion of the Tibetan Plateau’s weak lithospheric layer (middle-lower crust and lithospheric mantle) of southwestern China relative to the rigid Sichuan Basin/Ordos Block of the eastern West Qinling Syntaxis results in regional dextral shearing that shapes the Central Longitudinal Seismic Belt and defines the eastern Tibetan Plateau margin. The pre-existing E-W−trending Central China Orogenic Belt has been preserved above the brittle-ductile transition zone, and the northward movement of the deep lithospheric layer drives the deformation of the upper crust in the West Qinling Syntaxis. Our results, along with previous studies, suggest the presence of an intracontinental lithospheric interchange structure in central China. The continental rejuvenation of the West Qinling Syntaxis results from a combination of fault reactivation in the upper crust (Stage I, Eocene−Oligocene) and reworking of the deep lithosphere (Stage II, middle−late Miocene) related to the plateau-wide shift in stress accommodation ultimately driven by the redistribution of mass outward from the central Tibetan Plateau. At present, the transition zone between the high- and low-velocity anomalies along the Central Longitudinal Seismic Belt not only shapes the landscape boundary but controls the size and recurrence interval of earthquakes within the West Qinling Syntaxis in central China.

Conventional orogenic settings are largely confined to plate boundaries and their immediate vicinity. However, there is growing recognition that deformation of the continental lithosphere may extend for considerable distances away from active plate boundaries. The Mesozoic Qilian orogenic belt occupies a key position in East Asia and thus is important to consider when interpreting intracontinental deformation there. To determine when and how the North Qilian orogenic belt developed, multiple sets of samples collected from the Dahuang Mountain of the North Qilian orogenic belt were analyzed for apatite (U-Th)/He and zircon (U-Th)/He thermochronology. The results show that the study area experienced multiphase tectonic exhumation events that took place in the Early-Middle Triassic (250-235 Ma), Middle-Late Jurassic (170-150 Ma), and Early Cretaceous (130-110 Ma). This study reveals that the generation deformation and stress distribution in the Dahuang Mountain fold-fault system have the characteristics of temporal-spatial migration from N to S. Results indicate widespread, continuous exhumation and deposition in the Qilian Mountain due to multiplate interaction since the Mesozoic, persisting till at least late Miocene. Multiphase intracontinental deformation is driven by stresses at plate boundaries, with lithosphere serving as stress pathway.