The NNW Iranian Plateau and west Alborz within the Arabia-Eurasia collision zone are characterized by three main tectono-stratigraphic zones, crosscut by the Qezel-Owzan River Basin. The interplay between present-day deformation and climate, which control the landscape evolution of the region, is still poorly constrained. We addressed this gap by measuring millennial-scale erosion rates from 10Be-concentration in the Qezel-Owzan River sands along with topographic/climatic metrics analyses. Results reveal low erosion rates in the Plateau and relatively high in the west Alborz. The regional consistency of topographic parameters with geomorphology suggests that they control sediment fluxes in the Plateau, while the surface uplift, active thrust-faulting, and shallow crustal seismicity in the west Alborz are the main controlling factors. Climate has a secondary role on erosion rates. Furthermore, we calculated exhumation rates from published thermochronometric AFT/AHe ages to determine their relationship with 10Be short-term data. Results imply that the exhumation rates increased slightly in the Plateau and west Alborz from ∼26 to ∼10 Ma, simultaneous with hard collision processes between the Arabia-Eurasia. This trend accelerated from ∼10 to ∼2.8 Ma due to the isolation of the Caspian Sea and extreme base-level fall. From ∼2.8 to ∼2 Ma, base-level rise occurred under climate influence, and erosion rates decreased. Millennial-scale data show the erosion rate decreased from ∼2 Ma to the Present-day, which is attributed to the change in deformation style and fault kinematics from fold/thrusting to mainly strike-slip faulting. The significantly lower erosion rates in the Plateau compared to west Alborz suggest a relatively stable plateau surface.

Continental-scale strike-slip shear zones often record significant tectono-magmatism and dynamic deformation processes of the crustal lithosphere. However, the genetic relationships and timing among the anatexis, deformation, and initial shearing along a strike-slip shear zone have not been well defined. Here, we carried out detailed field, microstructural, zircon U–Pb geochronology, geochemical and EBSD texture analyses of leucogranites and migmatites in the Chongshan shear zone (CS-SZ). The results indicate that most migmatites and leucogranites exhibit strong shear deformation and well-developed high-temperature mylonitic microstructures. The quartz aggregated from foliated leucogranites developed dominant high-temperature prism and prism slip systems. The pre- and syn-kinematic crustal anatexis and localized weak zone mainly occurred from 35 to 29 Ma along the CS-SZ, which is closely related to the post-collisional extension and collapse of overthickened crust. Biotite dehydration melting formed pre- and syn-kinematic melts and leucogranites that further experienced fractional crystallization of plagioclase and K-feldspar during melting and subsequent melt migration and emplacement upward along the tectonic weak zone. The thinning and weakening of lithospheric crust further facilitated the initial and formation strike-slip displacement along the CS-SZ, which occurred from 29 to 20 Ma or much later to 18 Ma. Finally, we propose that crustal anatexis and upward migrating melts play a key role in controlling the thermal state and rheological strength of the crust, resulting in nucleation and initiation of the localized deep-seated shear zone that accommodates significant displacement for the India–Asia continental forward collision and intracontinental deformation.

The Trans-Mexican Volcanic Belt is an active continental volcanic arc related to subduction along the Middle America trench. It is characterized by intra-arc extension resulting into several major arc-parallel active fault systems and tectonic basins. The Acambay graben, one of the largest of these basins, is located near Mexico City, in the central part of this province. In 1912, a M 6.9 earthquake ruptured the surface along the northern border of the graben together with at least two other faults. In this paper, we analyze the paleoseismic history of the southern border of the Acambay Graben, with new observations made in one natural outcrop and four paleoseismological trenches excavated across branches of the Venta de Bravo Fault at the site where it overlaps with the Pastores Fault. We present evidence of at least two paleo-earthquakes that occurred between 12,190 ± 175 and 5,822 ± 87 cal year BP and between 647 ± 77 and 250 cal year BP. On one of these branches, we estimate a minimum slip-rate value between 0.1 and 0.23 mm/year for the last 12 ka and a mean recurrence interval of 8.5 ± 3 ka. By considering several likely rupture lengths along the Venta de Bravo and Pastores faults, we calculated a maximum possible magnitude of Mw 7.01 ± 0.27. Finally, by correlating events recorded along different faults within the Acambay Graben, we discuss several possible rupture coalescent scenarios and related consequences for Mexico City.

Cenozoic extension in the Western Mediterranean has been related to the dynamics of back-arc domains. Although, in most of its orogenic belts extension propagated into the fore-arc nappe domains. Here we revisit the structure, metamorphism and radiometric ages of the Tunisian Tell, where HP/LT rocks (350°C at 0.8 GPa), were exhumed by the sequential activity of extensional detachments after heating and decompression (410°C–440°C at 0.6–0.3 GPa) in a plate convergent setting. Normal faults thinning the Tunisian Tell detached at two different crustal levels. The shallower one cuts down into the Atlas Mesozoic sequence, involving Tellian Triassic evaporites in the hanging-wall forming halokinetic structures in the Mejerda basin late Miocene. The deeper-detachment bounds metamorphic domes formed by marbles and metapsammites from the Atlas domain. Illite crystallinity on Triassic rocks shows epizonal to anchizonal values, at deep and intermediate structural depths of the Tell-Atlas nappe belt, respectively. New U-Pb 49.78 ± 1.28 Ma rutile ages from Tellian metabasites, together with existing phlogopite 23–17 Ma K-Ar ages in Atlas marbles from the footwall of the deepest detachment, indicate a polymetamorphic evolution. The Tell rocks underthrusted the Kabylian flysch in the early Eocene. Further, early Miocene shortening thrusted the metabasites over lower-grade sediments, producing HP/LT metamorphism and ductile stretching at the base of the Atlas belt. The exhumation of midcrustal roots of Western Mediterranean nappe belts after tectonic shortening is a common feature related to tearing at the edges of the subduction systems and inboard delamination of their subcontinental lithospheric mantle.

Bending of ribbon continents or arcs is an important tectonic process for reconstructing central Asia. Formation of the striking Tuva-Mongol Orocline by closure of the Mongol-Okhotsk Ocean (MOO) has long been proposed, but coupling of the two geological events has not been well illustrated, hindering our understanding of tectonic evolution of central Asia. In order to constrain age of initial closure of the MOO in its western segment and formation of the Tuva-Mongol Orocline, we performed paleomagnetic studies on the Late Triassic clastic rocks in the Amuria Block (AMB; 17 sites) and the Tarvagatay Block (TVB; 10 sites) of the western Mongolian blocks (WMB) on both sides of the Mongol-Okhotsk Suture. Rock magnetic investigations show hematite and magnetite as main magnetic carriers of the characteristic remanent magnetization (ChRM). The ChRM directions from both regions pass fold and/or reversal tests and can be considered as primary remanent magnetization. Combining the overlapped new paleomagnetic poles (AMB: λ/φ = 70.4°N/233.8°E, A95 = 4.6°; TVB: λ/φ = 70.5°N/248.2°E, A95 = 9.0°) with geological evidence, we propose that the bending of the WMB following its collision with the Siberia Craton resulted in the Late Triassic closure of the MOO in its western segment, and initiated the formation of the Tuva-Mongol Orocline.

The Sichuan basin, located adjacent to the eastern margin of the Tibetan Plateau, serves as an ideal marker for testing the extrusion process of the plateau. The basin is seismically active, with the strongest earthquake, the 2008 Mw 7.9 Wenchuan earthquake, occurring in the Longmen Shan range along its northwestern edge. A new regional compilation of focal mechanism solutions of earthquakes in and surrounding the basin reveals that a large fraction of the events have focal depths ranging between 8 and 25 km, corresponding to the crystalline basement of the basin. Seismic deformation involves right-lateral oblique reverse faults, mostly trending northeast–southwest, similar to the kinematics of the mainshock of the Wenchuan earthquake. Shallow earthquakes (3–8 km) suggest that some of the seismic faults rupturing the crystalline basement are growing toward the surface. To the southwest, the seismicity transitions to activity along the left-lateral Xianshuihe–Xiaojiang fault zone. The spatial relationship between these two sets of fault zones is consistent with a model in which the Sichuan basin responds to the southeast extrusion of the Chuan-Dian block at the southeast margin of the plateau by a counterclockwise bookshelf rotation of the crystalline basement. This deformation pattern initiated ∼4–2 Ma, as shown by the age of the Xiaojiang fault segment. The history of left-lateral movement along the Xianshuihe-Xiaojiang fault can be traced back to ∼12 Ma when the eastward growth of the Tibetan Plateau resulted in the shortening of both the Longmen Shan thrust belt and the sedimentary over the Sichuan basin.

Ephemeral subaerial salt diapirs are gravitationally unstable and vulnerable to climate and tectonic activity due to the rheology and incompressibility of rock salt. Quantifying the kinematics of subaerial salt and clarifying the role of tectonics, surface processes, and climate in reshaping the surface salt morphology provides an invaluable opportunity to explore the interactions between Earth’s spheres on a much shorter timescale. With diverse exposed salt diapirs and potential motions, the Kuqa fold-thrust belt (KFTB), NW China, represents an optimum natural laboratory to understand subaerial salt kinematics. Here, we integrated ascending and descending geometries of Sentinel-1 synthetic aperture radar images with optical remote sensing data, seismic profiles, digital elevation models, and meteorological records to explore the potential correlation between subaerial salt motions and geomorphic, tectonic, and climatic factors. Using the interferometric synthetic aperture radar technique, we observed a maximum of 25 mm/yr in vertical and 40 mm/yr in horizontal surface salt deformation in the KFTB from 2014 to 2020. Our findings demonstrate a gravity spreading dominant system, where topography exerts a primary control on the surface displacement patterns of salt structures, while weather variables influence deformation mainly by softening salt and facilitating gravity-driven salt flow.

Reinterpretation of the Organyà Basin, based on new detailed field observations and subsurface data, emphasizes the key contribution of Upper Triassic evaporites in the tectono-sedimentary evolution of the South-Central Pyrenees. Results are integrated in a 65-km long restored cross-section through the Serres Marginals, Montsec and eastern Organyà salt-related depocenters. The reconstructed part of the Jurassic–Cretaceous northern Iberian salt-rich rifted margin shows a template characterized by inherited Permo-Triassic basement normal faults and an initial salt thickness of 0.7 km to the south and 1.5 km to the north. The Organyà Basin is part of the South Pyrenean Diapiric Province, a large system of salt related depocenters and minibasins, that is limited to the north by the more than 120-km long Senterada salt wall complex separating the supra-salt and sub-salt domains in the Southern Pyrenees. Three main stages of diapiric activity are recognized along the northern Iberian margin from Asturias to the Eastern Pyrenees: a Jurassic early salt mobilization; a latest Jurassic–middle Albian main diapiric evolution associated with rifting; and a Campanian–Miocene diapiric reactivation during basin inversion that produced salt welds and thrust welds and translated the salt province some 60 km to the south.

The evolution of the Apennine wedge has seen the time-space migration of the forebulge, foredeep, thrust wedge, and back-arc extension phases in the wake of the Eastward rollback of the subducting Adria slab. In this framework, thrusting and post-orogenic extensional faulting have occurred in two parallel forelandward-migrating ribbons, with extensional deformation overprinting or partly exploiting anisotropies of the inherited thrust system. Here, we explore the tectonic framework and the timing of thrusting and subsequent negative inversion of the Circeo thrust, one of the major thrusts in the inner portion of the central Apennines, with the main aim to constrain the timing and mode of the compression to extension switch. Structural analysis, carbonate C and O and clumped isotopes analysis, X-ray diffraction of clay minerals, and U-Pb dating of calcite slickenfibers have been integrated with seismic interpretation, cross-section balancing, and 1D burial and thermal modeling. We show that the Circeo thrust developed during Langhian-Serravallian time. Its extensional reactivation is dated at the Serravallian, during the stacking of an underlying thrust slice, before the onset of Pliocene back-arc extension in the area. Combination of our data with the age of thrusts, extensional basins, and base of the foredeep infill of the central Apennines, demonstrates that forelandward migration of the foredeep-thrust system occurred at variable velocities. Accelerations and decelerations are synchronous, respectively, with the opening of the Liguro-Provençal and Tyrrhenian back-arc basins and with the interluding quiescent period.

Previous models of strike-slip basins do not consider the rotation of the basin itself; however, we show that the Tanakura transtensional basin in Japan was rotated and propose that this basin rotation was related to rifting caused by back-arc spreading. The Tanakura Basin was formed by displacement along the Tanakura Fault Zone, one of the major active transform faults during the opening of the Sea of Japan. We carried out paleomagnetic analyses and U–Pb dating of the Neogene Tanakura Basin fill rocks. We present a revised, high-precision stratigraphic record for the Neogene Tanakura Basin fill sequence shows that vertical-axis counter-clockwise rotation occurred between ∼17.2 and ∼16.6 Ma. Comparison with paleomagnetic data from adjacent areas shows that rotation was restricted to the basin. In addition, the timing of basin rotation corresponds to the rifting phase of the Tanakura Basin, suggesting that rapid basin subsidence owing to rifting and rapid basin rotation owing to strike-slip faulting occurred simultaneously. The Tanakura Basin has the characteristics of both rift and transtensional basins that have experienced rotation. This study reveals the detailed relationships between the development and rotation of the Tanakura Basin: rifting-related subsidence accompanied by basin rotation. Rifting owing to back-arc spreading may have been accompanied by tectonic basin rotation in Northeast Japan, leading to variations in the magnitude and age of rotation, as the rifting occurred at different times in different locations.

Orogenic plateaus of continental collision zones exhibit landforms and fluvial networks that retain first-order information on their topographic evolution and vertical growth. The inversion of river longitudinal profiles allows to reconstruct the base level fall history of plateaus, supporting the study of landscape evolution in the frame of geodynamic models. The Eastern Anatolian Plateau (EAP) of the Arabia-Eurasia collision zone is a plateau at an early stage of development. It stands at ∼2,000 m, presents endorheic basins, and is drained by three main river networks. Seismic data indicate a thinned lithospheric mantle that explains the late Cenozoic volcanic activity. Despite the number of studies on the EAP uplift, its history is still debated. In this study we investigated the EAP hydrography and topography, and we inverted the longitudinal profile of one of the main rivers: the Arax River. The results describe a high-standing, low-relief plateau drained by a hydrography, controlled by active tectonics. Longitudinal profiles and χ-plots illustrate rivers in disequilibrium with channel steepness increasing downstream. The elevation of marine deposits indicates a surface uplift of ∼2,000 m, ∼500 m of which are of residual topography. This upheaval occurred by two increases: the first one at 10–11 Ma with the opening of a slab window and the arrival of a mantle flow from Arabia and the second one at ∼5 Ma with the continued inflow coupled with isostasy. Our results describe the early stage of collisional plateau development, distinguishing the contribution of deep processes and isostasy to the topographic growth.

New geophysical profiles across the central Dead Sea Transform (DST) near the Sea of Galilee, Israel, and surrounding highlands, augmented by static stress modeling, allow us to study continental transform plate deformation. The DST separates a ∼10 km thick sedimentary column above a thinned (16-23 km) crust to the west from a ∼7 km column above a ∼30-km thick crust to the east. Crustal thinning starts under the DST, as observed also farther south, indicating that the DST is indeed located along the boundary between the Arabian plate and its continental margin. Moho step here is gradual. The DST’s eastern shoulder dips westward toward the DST unlike the upward flexed shoulder observed farther south, perhaps delineating the northern limit of a thinner and hotter lithosphere. The shape of the Sea of Galilee is modeled as an asymmetric pull-apart basin formed by a left-lateral stepover of 2.6 km between slightly divergent and underlapping strike-slip fault strands dipping 70° to the west. Reflection data indicate that these strands are not connected. Several fault traces within the Sea of Galilee have previously been suggested to carry part of the relative plate motion. However, given slip along the main DST faults, Coulomb stress will increase only on fault portions in the northern part of the lake, in accord with the geographical distribution of seismicity, suggesting that these faults are likely secondary. Mismatch between the DST strand locations in the geophysical profiles and the subsidence model, may reflect temporal changes in fault geometry.

In an orogen-foreland basin system, syn-orogenic sedimentation and deformation records within the foreland basin provide critical evidence for understanding uplift and erosion processes of adjacent orogenic belts. Foreland fold-and-thrust belts (FTBs) are widely developed around the Tian Shan range, Central Asia. Problem of how crustal shortening accumulates and propagates from the Tian Shan to adjacent foreland basins is essential for understanding the overall dynamics of Tian Shan. In this study, we interpreted three high-resolution seismic reflection profiles to estimate the magnitude and distribution of Cenozoic shortening across the Eastern Kuqa FTB, South Tian Shan foreland. Combined with well-dated syntectonic stratigraphy, we further evaluate the timing, rate, and migration of the deformation front of the Kuqa FTB. Our results suggest that the Kuqa FTB's total crustal shortening increases westward. The distribution of crustal shortening across secondary structural belts shows a gradual, basinward decrease, which can be explained by the telescoped mechanism. Propagation rates of the Kuqa FTB's deformation front indicate an episodic propagation of the foreland thrust wedge, with an acceleration after ∼12 Ma. Similar episodic propagation pattern has also been observed in other foreland FTBs around the Tian Shan, but they show significant spatio-temporal variations in the propagation stages and related rates.

Dating the timing of ductile shear deformation is critical to the understanding of complex, multi-episode kinematics that commonly occur within the study of continental tectonics. The Tan-Lu fault zone (TLFZ) in East China is a lithospheric discontinuity that records multistage sinistral strike-slip shearing during Mesozoic time. Herein, based on field mapping, pressure-temperature estimates via microstructures, quartz lattice preferred orientations, and geothermobarometer analysis, and U–Pb geochronology, we present a detailed examination of a portion of the southern TLFZ known as the Fucha Shan ductile shear zone. Two phases of sinistral ductile shear deformation in the shear zone are identified. The main phase occurred under amphibolite-facies metamorphic conditions (500°C–650°C, 2.8–5.2 Kbar). U–Pb dating of synkinematic titanite indicate deformation occurred ca. 142–140 Ma. This age information is consistent with U–Pb dating of zircon from crosscutting granitic dikes that provide an upper limit of the shearing of ca. 134 Ma. A later, but less well-developed phase of sinistral ductile shearing variably overprints older structures within the Fucha Shan shear zone at greenschist-facies metamorphic conditions. U–Pb dating of apatite grains in rocks that record this later event are interpreted to indicate that shearing occurred ca. 118–108 Ma. These results provide new insight into Early Cretaceous shear deformation history within the southern TLFZ in the context of the late Mesozoic intracontinental deformation in East Asia.

Structures associated with Ediacaran-Ordovician alkaline magmatism and the timing of rare earth element (REE) mineralization in the Wet Mountains, CO, were analyzed using field, geophysical, and U-Th-Pb isotope methods to interpret their tectonic setting in the context of previously proposed rift models. The Wet Mountains are known for thorium and REE mineralization associated with failed rift-related, Ediacaran-Ordovician alkaline intrusions and veins. Structural field data indicate that alkaline dikes and mineralized veins are controlled by a system of northwest-striking, high-angle faults and tension fractures formed in a 040°-directed extensional regime. Magnetic and surface expressions of Democrat Creek and McClure Mountain complexes show tectonic elongation toward ∼045°, consistent with NE-directed extension. Magnetic data also suggest the existence of a fourth, previously unrecognized mafic-ultramafic complex of inferred Cambrian age with a similar elongated orientation. Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) 208Pb/232Th analysis of low-uranium zircon from carbonatite dikes and in situ 206Pb/238U LA-ICP-MS analysis of monazite in mineralized dikes yielded 465 ± 18 Ma and 489 ± 33 Ma ages, respectively. These ages are consistent with the expected age based on slightly older, cross-cut syenite dikes and the hypothesized Ordovician end to failed rift-related magmatism. The Ediacaran-Ordovician age of alkaline magmatic rocks and the associated northeast-directed extension direction are similar to those of the along-strike, Ediacaran-Cambrian Southern Oklahoma Aulacogen. Therefore, the failed rift system in the Wet Mountains is interpreted to be a northwestern continuation of the Southern Oklahoma Aulacogen with carbonatite magmatism and thorium/REE mineralization representing late intrusive phases.

Himachal region of Northwest Himalaya exhibits the widest structural re-entrant in Kangra region and significant strain partitioning along the frontal and hinterland out-of-sequence faults. We report results of continuous GPS measurements from 10 new sites in the region and analyse them along with the previously published results to constrain the ongoing arc-normal and arc-parallel convergence rates at 16.5±1.1 mm/yr and 4–5 mm/yr respectively. Thus, the ongoing convergence is oblique by 15°-20°. The Main Himalayan Thrust (MHT) is strongly coupled up to ∼100 km from the Main Frontal Thrust (MFT) but displays significant variation in coupling in the transition zone across the Kangra re-entrant and the adjoining western salient. Joint analysis of the coupling variation, the geologically inferred MHT geometry variations and the local topographic anomaly pattern strongly suggests the possibility of a potentially active, strain accumulating segment of MBT along the southern margin of Dhauladhar ranges in Western Himachal region, which is also proposed to be influencing the long-term topographic growth in the region. Although a general agreement is observed between the long-term shortening rates along the active faults and the estimated geodetic convergence in this region, the ensuing discussion highlights their complex relationship in terms of temporal and spatial variability in the fault activity and elastic-inelastic deformation. We use the fault orientation and the estimated convergence rate to geometrically constrain a mean dextral slip-rate of 4.4–5.7 mm/yr along a recently discovered Khetpurali-Taksal fault, which is proposed to partition the majority of ongoing arc-parallel deformation along it.

The 2016 moment magnitude 7.8 Kaikoura, New Zealand, earthquake occurred at the southern end of the Hikurangi subduction zone where the upper plate above the shallow megathrust is exposed sub-aerially. As a result, the substantial co-seismic deformation in the upper plate above the megathrust rupture was observed geologically and geodetically. We explore the relationship between this surface faulting and the subduction megathrust rupture and find that the greatest upper plate fault slip occurred coincident (in time and location) with the megathrust rupture. Models of Coulomb stress change demonstrate that these surface faults become positively loaded as the upper plate rebounds during the megathrust event, favoring fault slip. In addition, during the megathrust rupture these faults terminate against an uncoupled subduction plate interface. We simulate the effects of decoupling at the base of these faults and find that very large fault slip is an expected consequence of this decoupling, allowing near-complete strain release. In contrast, typical strike-slip faults, pinned at their base, would have lower amounts of fault slip. These two conditions—increased Coulomb stress and basal decoupling—combine to produce the extreme co-seismic upper plate faulting observed above the shallow Kaikoura megathrust earthquake. Similar conditions occur in other global subduction zones, but in most subduction zones the region above the coupled megathrust is underwater and poorly observed. Our analysis of the Kaikoura earthquake indicates a need to reevaluate patterns of strain accumulation and release in these regions, rather than assuming simple models of elastic rebound.

Thermochronologic results from zircon fission track and (U-Th)/He data collected across the Patagonian batholith, basement and thrust belt of the southern Patagonian Andes between 51°S and 53°S resolves new spatiotemporal patterns of Paleogene rock cooling that allows us to reconstruct deformational and erosional events along- and across-strike. Our study applies a novel modeling strategy, the Path Family Approach, to filter geologically plausible thermal solutions from inverse modeling results for rocks in this study according to a sample's structural and tectonic context. Our results identify minimal cooling and interpreted exhumation of batholith rocks throughout the Paleogene. However, in the western domain we identify synchronous cooling of Jurassic volcaniclastic rocks in the thrust belt both along- and across-strike between 50 and 35 Ma, which we interpret as a period of out-of-sequence deformation that coincides with the start of a distinct period of orogenesis in the Fuegian Andes (54°S). This finding may suggest that the southern Patagonian Andes and Fuegian Andes evolved as a connected orogenic system along the bend of the Patagonian orocline. In the central domain, modeled cooling of thermally reset Cretaceous basinal strata from 60 to 50 Ma corresponds to a well-recognized erosional unconformity in the adjacent Cenozoic foreland depocenter, indicating that contemporaneous exhumation occurred beyond the margins of the basin. Although not diagnostic, exhumation within the orogenic belt, beyond the Cenozoic foreland basin, provides a new regional context to interpret the cause of this regional erosion event. Collectively these results inform the Paleogene tectonic evolution of the orogen.

The Magallanes-Fagnano Fault is an active left-lateral strike-slip fault that cuts across Tierra del Fuego, forming the boundary between the South American and the Scotia plates. This fault may trigger strong earthquakes, as documented by the occurrence of two Mw ≥ 7.5 in December 1949. However, this region is characterized by one of the shortest historical archives in the world and by a growing population. The geological record is therefore needed in order to characterize the seismic information over a longer time scale and to improve the seismic hazard assessment. We conducted extensive field work, neotectonic mapping and excavated two paleoseismic trenches across one of the sharpest tectonic scarps in the Eastern onshore portion of the fault. Using scarp-derived colluvial wedges, cross-cutting relations, and 28 radiocarbon samples, we document evidences of at least six paleo-earthquakes during the Holocene. Paleoseismic record is particularly accurate for the last two thousand years, for which period we determine an average recurrence interval of 1080 ± 150 years. For repeated earthquakes of same magnitude as the 1949 event, this recurrence interval is compatible both with the known geodetic and geomorphic slip rates. However, “paired earthquakes” in less than one or two centuries may also occur, suggesting that fault behavior could be characterized by irregular seismic cycles.

The eastern European Alps are shaped by the indentation of Adria into Europe. Recent tomography, depicting detached slab fragments, has been interpreted as evidence of continuous southward subduction of European lithosphere, contrary to an often-invoked subduction polarity reversal. Orogen-scale exhumation, driven by rock displacement along active faults, may reflect subduction polarity within the framework of doubly-vergent Coulomb wedge theory, provided the absence of rheological contrasts across the colliding plates. Low-temperature thermochronology can evaluate crustal cooling in response to changes in tectonic and erosional boundary conditions. This study investigates the consistency of observed crustal re-organization, exhumation, and mantle processes in the Eastern Alps. Thermo-kinematic forward models driven by reconstructions of crustal shortening along the TRANSALP geophysical transect were subjected to variations in shortening rates, thermophysical parameters, and topographic evolution, supplemented by new fission-track data. The thermo-kinematic models reproduce: (a) the orogen-scale structural geometry, (b) the distribution of thermochronometer ages, (c) observed time-temperature paths, and (f) the present-day surface heat flux. Results suggest that exhumation is driven by rock displacement along active faults without the need to involve mantle-driven buoyancy forces. Taken together, the results identify two possible scenarios: if the Tauern Ramp is a retro-thrust and the southward shift of deformation in the Southern Alps is a response to new Coulomb-wedge conditions, then our results support a Mid-Miocene reversal of the subduction polarity. Alternatively, crustal deformation does not reflect mantle processes entailing a high degree of inter-plate decoupling.