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Western Anatolia is one of the most rapidly extending and seismically active regions in the world. The circa N-S extension since the Early Miocene caused the formation of E-W trending major grabens and intervening horsts, having earthquake potentials with magnitude ≥5. The E-W oriented Büyük Menderes graben cross-cuts the broadly N-S oriented Bozdoğan and Karacasu grabens, of which the boundary faults of the latter are the source of seismic activity. Geomorphic indices, including drainage basin asymmetry, mountain front sinuosity, valley-floor width to valley height ratio, stream length-gradient index and normalized channel steepness index, were used to evaluate the boundary fault segments of the Bozdoğan and Karacasu grabens. The results indicate that both grabens are tectonically active and therefore regions of earthquake potential, consistent with the epicenters of earthquakes. Thus, it can be inferred that fault segments of second-order grabens, which are crosscut by the boundary faults of seismically active main depressions, are apparently reactivated by ongoing tectonism and may represent seismic activity. This suggestion applies also for similar basins located in the western Anatolia.

Lunar grabens are the largest tensional linear structures on the Moon. In this paper, 17 grabens were selected to investigate the dips and displacement–length ratios (γ) of graben-bounding faults. Several topographic profiles were generated from selected grabens to measure their rim elevation, width and depth through SLDEM2015 (+LOLA) data. The differences in rim elevation (∆h) and width (∆W) between two topographic profiles on each graben were calculated, yielding 146 sets of data. We plotted ∆h vs. ∆W for each and calculated the dip angle (α) of graben-bounding faults. A dip of 39.9° was obtained using the standard linear regression method. In order to improve accuracy, large error data were removed based on error analysis. The results, 49.4° and 52.5°, were derived by the standard linear regression and average methods, respectively. Based on the depth and length of grabens, the γ value of the graben-bounding normal fault is also studied in this paper. The γ value is 3.6 × 10−3 for lunar normal faults according to the study of grabens and the Rupes Recta normal fault. After obtaining the values of α and γ, the increase in lunar radius indicated by the formation of grabens was estimated. We suggest that the lunar radius has increased by approximately 130 m after the formation of grabens. This study could aid in the understanding of normal fault growth and provide important constraints on the thermal evolution of the Moon.

Lakes are sensitive indicators of the balance between accommodation and sediment supply, recording high‐resolution changes in palaeoenvironmental conditions. Long‐lived rift lake basins, however, are predominantly controlled by episodic accommodation changes and pronounced basinward facies shifts, complicating the generalisation of tectonic and climatic controls on rift lake successions. This study proposes a sequence framework and depositional pattern for asymmetric half‐grabens in syn‐rift lake basins by characterising the lacustrine fan‐delta deposits of the Lower Cretaceous Shahezi Formation in the Songliao Basin. Detailed sedimentologic and petrographic analyses identified 24 lithofacies categorised into seven facies associations. A sequence stratigraphic framework was constructed to outline the tectono‐stratigraphic evolution during the syn‐rift phase. The results indicate that the syn‐rift Lishu palaeo‐lake is characterised by its relatively small size, steep slopes, poorly developed and siliciclastic‐dominant shoreline strata and significant input of allochthonous biodetritus. The syn‐rift deposits show a distinct threefold conglomerate–sandstone–mudstone motif, with a complete cycle comprising a prolonged retrogradational phase (LST and TST) and a brief progradational phase (HST). Basin‐bounding faults accelerated hinterland erosion and increased sediment feeder system slopes by rotating hangingwall blocks; consequently, rapid sediment transport and localised gravitational collapse caused the common occurrence of soft‐sediment deformation structures and sublacustrine fan conglomerates. The substantial increase in accommodation space, resulting from fault‐generated subsidence, triggered lake expansion and further contributed to the development of transgressive system tracts and continuous mudstone deposition. These mudstones, rich in terrigenous organic matter and allochthonous fossils, correlate with carbonaceous mudstones, coals and conglomeratic sandstones in proximal overfilled sections, indicating a dynamic interplay between fan delta progradation and Lake Shoreline transgressions. This study proposes a depositional model within a sequence stratigraphic framework for non‐marine sediment accumulation in asymmetric half‐grabens bounded by active faults. The findings offer insights that complement existing models developed for marine rift systems. A consistent model for the sequence framework and depositional pattern of asymmetric half‐grabens in syn‐rift lake basins bounded by active faults has been established, complementing existing models for marine rift successions. Syn‐rift lake basins are characterised by relatively small dimensions, steep slopes, poorly developed shoreline strata dominated by siliciclastics and significant input of allochthonous biogenic detritus.

Karapınar (Konya, Turkey) is located in the central part of the Anatolian micro-plate which is characterized by differently oriented Neogene–Quaternary horst – graben structures. The basement of the region is composed of Mesozoic–Paleogene rocks. In the various Neogene basins, Miocene–Pliocene sedimentary and volcanic rocks overlie the basement rocks and form the secondary rock units. The youngest units are Plio-Quaternary aged terrestrial sediments and volcanics. The main structure of the study area consists of WNW-ESE and NE-SW trending intersecting graben-horst structures and the normal faults forming them. The approximately WNWESE trending basins are filled with Miocene–Pliocene sediments, while the NE-SW trending basins are filled with Pliocene–Quaternary sediments. Kinematic studies show that the faults in the study area are developed in all directions and the distribution of the slicken lines indicates that there is multidirectional crustal extension. The principal stress axes obtained from all the kinematic data show that σ1 is nearly vertical, σ2 and σ3 are horizontal. If all faults are assumed to have been formed due to the same stress system, the study area is predominantly elongated in the NW-SE direction. However, detailed field observations and structural analyses indicate that the NE-SW trending fault systems are younger than the WNW-ESE trending faults. This indicates that firstly NNE-SSW and then NW-SE crustal extension developed in the study area respectively.

The Fanshi Basin is one of the NE–SW-striking depocentres formed along the northern segment of the fault-bounded Shanxi rift. In order to understand the crustal driving stresses that led to the basin formation and development, a palaeostress analysis of a large quantity of fault-slip data collected mainly at the boundaries of the basin was accomplished. The stress inversion of these data revealed three stress regimes. The oldest SR1 was a Neogene stress regime giving rise to a strike-slip deformation with NE–SW contraction and NW–SE extension. SR1 activated the large faults trending NNE–NE, i.e. (sub)parallel to the main strike of the Shanxi rift, as right-lateral strike-slip faults. It was subjected to the Shanxi rift before the activation of the Fanshi Basin boundary fault, i.e. the Fanshi (or Wutai) fault, as a normal fault. The next is a short-lived NE–SW extensional stress regime SR2 in early Pleistocene time, which shows the inception of the basin’s extension. A strong NW–SE to NNW–SSE extensional stress regime SR3 has governed the northern segment of the Shanxi rift since late Pleistocene time and is the present-day extension. It gave rise to the current half-graben geometry of the Fanshi Basin by activating the Fanshi (or Wutai) fault as a normal fault in the southern part of the graben. Because of the dominance of the NW–SE to NNW–SSE extension, which is perpendicular to the NE–SW extension, mutual permutations between σ3 and σ2 due to inherited fault patterns might have occurred while the crustal stresses in the Fanshi Basin changed from the SR1 to SR3 stress regimes.

This study aims to discuss the history and significance of the Cenozoic basins in Sardinia, both before and after the rotation of the Corsica-Sardinia Block, within the Western Mediterranean geodynamic framework, taking into account new seismic data. A grid of 2D seismic profiles with better penetration, improved processing, and calibration by 2 wells (Oristano-1 and Campidano-1) brought novel findings. Two tectonic phases, pre-rotation of the Corsica-Sardinia Block, are now recognized: Phase 1 previously unknown, resulted in the formation of a narrow (20 km) half graben infilled by 3 to 4 km thick syntectonic continental sediments. By comparison with the Paleogene basins of S France, its formation could have started in the Late Eocene. It could include: 1-the syntectonic continental Chattian Ussana Formation of Sardinia, whose base corresponds to the onset in Latest Rupelian-Earliest Chattian time of the calc-alkaline volcanics crossing Sardinia 2-possibly also below part or unknown time equivalent of the post-Pyrenean tectonics Middle-Upper Lutetian to Late Rupelian fluvial-lacustrine Cixerri Formation. Phase 2 resulted in the formation above it, of the wider (more than 50 km) Sardinia Graben System (SGS) more than 200 km long, crossing entire Sardinia from S to N. It is characterized by the deposition of 2 to 3 km thick sediments, continental, deltaic to deep marine in the axis, from the Latest Chattian to the Early Burdigalian. The SGS infilling is like the series deposited in the grabens onshore Southern France and on the margin of the Gulf of Lion. Since the Late Chattian a transgression of the sea from the south became possible in the SGS and the Ligurian-Provençal rift, through deep corridors created between Sardinia and the Balearic Islands. The characteristics of the SGS, its easternmost location in the western Mediterranean extensional system, its boundaries to the north and south linked respectively to the termination of the Provençal and Catalan-North Balearic transfer-transform fault systems, are in favor of the SGS being a failed arm of the W Mediterranean Rift System. Formed after the rotation of the Corsica Sardinia Block, the narrow (20 km) Campidano Graben is now interpreted as a transpressional basin, of Late Miocene (Tortonian) to Recent age. It is superimposed on the western part of the SGS and on the deeper Oligocene half-graben. Its boundaries are major faults of the SGS, reactivated as strike-slip faults with an inversion of the basin sediments of more than 1000 m on its eastern side. It allows interpreting the Campidano basin as a transpressional basin resulting from a regional N-S oriented compressional stress on the pre-existing SGS. It agrees with the generalized inversion of the Neogene basins since the Late Miocene in the western Mediterranean due to the Africa-Eurasia convergence.

Grabens, or valleys formed during extensional tectonic events, are common but rarely observed during formation. In November 2023, inelastic surface deformation formed abruptly along Iceland's plate boundary in Grindavík. We documented graben formation in real‐time through satellite mapping (InSAR), seismicity, GNSS data, repeated lidar surveys, and field mapping. Five normal faults and ∼12 fissures ruptured the surface delineating two grabens separated by a horst, a context not present in other contemporary case studies. The graben normal faults slipped rapidly (over hours) and maximum surface motions coincided with the occurrence of turbulent seismic swarms in both space and time. Although 3 eruptions took place ∼15 km northeast of Grindavík from 2021 to 2023, attributed to magma intrusions (i.e., dikes), none of these also formed grabens. Thus, the Grindavík grabens shows evidence for tectonic origins. Real‐time monitoring of these phenomena provide insight into graben formation on Earth and potentially on other planets. Plain Language Summary Valleys known as grabens, typically caused by extensional tectonic events, are a common geological feature, yet their formation is rarely observed. In November 2023, such two grabens suddenly emerged along the boundary between tectonic plates in the town of Grindavík, Iceland. The grabens were shaped by tectonic activity expressed by a swarm of earthquakes and associated ground deformation and resulted in normal faults rupturing the surface and cutting through houses, linear infrastructure including water pipelines and roads within Grindavík. We document the grabens and horst in real time using satellite mapping (InSAR), geodetic GPS data, repeated drone surveys, field mapping, and seismic recordings from a local seismic network. The combination of these data provide unprecedented level of precision in characterizing surface and sub‐surface deformations, especially when maximum surface motions correlate with a turbulent seismic activity in both space and time. Critically, following the formation of the grabens, a series of intensive through short‐lived eruptions happened in December 2023, January 2024, February 2024, March, and May 2024 within the northernmost portion of the grabens. Our observations provide valuable insights into the natural laboratory of Iceland and contribute to the understanding of plate tectonics both on Earth and other planets. Key Points The 2023 seismic swarm and extension lead to a graben forming that coincides in time and space along Iceland's plate boundary During 2021 to December 2023 only one tectonic graben formed, although 4 eruptions have taken place The graben in Grindavík, Iceland is wider at the surface than most recently documented grabens (∼4,500 m vs. <1,000 m)

A detrital zircon U–Pb laser ablation–inductively coupled plasma–quadrupole mass spectrometry (LA-ICP-QMS) provenance study was undertaken on samples selected from the Lower Gondwana successions preserved in the fault-bounded Bokaro and Jharia basins in India to investigate the provenance of the sediment and determine whether the strata were deposited in isolated syn-depositional graben basins or formed part of a wider regional depositional system. A total of 730 concordant U–Pb detrital zircon ages revealed six distinct age fractions: (i) a latest Neoproterozoic to earliest Cambrian age fraction (530 to 510 Ma), which tails down in some samples to older Neoproterozoic ages (650 to 630 Ma); (ii) a major age fraction with an age peak of earliest Neoproterozoic (950 Ma), accompanied in some samples by a twin Mesoproterozoic peak (1000 Ma); (iii) a middle Mesoproterozoic age fraction (1330 to 1300 Ma); (iv) a prominent earliest Mesoproterozoic zircon age fraction (1600 Ma); (v) a less well-defined late Palaeoproterozoic zircon age fraction (2100 to 1700 Ma, or 1600 Ma); and (vi) an Archaean zircon age fraction that typically comprises two zircon age fractions, namely zircons with early Neoarchaean ages (2800 to 2750 Ma) coupled with zircons with ages older than 3100 Ma. Comparison of these newly obtained age fractions with detrital zircon age data presented by Veevers & Saeed (2009) shows similarities with the Gondwana strata of the Mahanadi and Pranhita–Godavari basins, implying that strata preserved in the fault-bounded Gondwana basins in central east India formed part of a much wider regional depositional system and that they were not deposited in isolated half-graben or graben basins. Potential source regions to the Gondwana strata of the Bokaro and Jharia basins include the Eastern Ghats Mobile Belt and rock units in Antarctica.

We used physical models to investigate the structural evolution of segmented extensional rifts containing syn-rift evaporites and their subsequent inversion. An early stage of extension generated structural topography consisting of a series of en-échelon graben. Our salt analog filled these graben and the surroundings before continued extension and, finally, inversion. During post-salt extension, deformation in the subsalt section remained focused on the graben-bounding fault systems, whereas deformation in suprasalt sediments was mostly detached, forming a sigmoidal extensional minibasin system across the original segmented graben array. Little brittle deformation was observed in the post-salt section. Sedimentary loading from the minibasins drove salt up onto the footwalls of the subsalt faults, forming diapirs and salt-ridge networks on the intra-rift high blocks. Salt remobilization and expulsion from beneath the extensional minibasins was enhanced along and up the major relay or transfer zones that separated the original sub-salt grabens, forming major diapirs in these locations. Inversion of this salt-bearing rift system produced strongly decoupled shortening belts in basement and suprasalt sequences. Suprasalt deformation geometries and orientations are strongly controlled by the salt diapir and ridge network produced during extension and subsequent downbuilding. Thrusts are typically localized at minibasin margins where the overburden was thinnest, and salt had risen diapirically on the horst blocks. In the subsalt section, shortening strongly inverted sub-salt grabens, which uplifted the suprasalt minibasins. New pop-up structures also formed in the subsalt section. Primary welds formed as suprasalt minibasins touched down onto inverted graben. Model geometries compare favorably to natural examples such as those in the Moroccan High Atlas.

This study constrains the stratigraphy, age, and tectono-sedimentary evolution of the Datça Graben (southwestern Turkey) through integrated magnetostratigraphy, zircon (U-Th)/He geochronology, sedimentological analysis, and fault kinematic studies. The basin, developed along the southwestern margin of Anatolia under N-S extension, preserves ~ 350 m of fluvio-lacustrine to shallow-marine deposits, primarily assigned to the Yıldırımlı Formation. Two interbedded tuff layers yield zircon (U-Th)/He ages of 1.56 ± 0.10 Ma and 1.44 ± 0.10 Ma, constraining deposition between 1.78 and 0.78 Ma (Calabrian Age) when correlated to the Geomagnetic Polarity Time Scale. Magnetostratigraphy records a reversed-normal-reversed polarity sequence within subchrons C1r.2r, C1r.1n, and C1r.1r. The basin fill dips southward, with thicker accumulations along the southern boundary fault, indicating an asymmetric half-graben geometry dominated by southern-margin subsidence. Syn-depositional growth faults, paleostress analysis, and mesoscopic fault kinematics indicate persistent N-S extension with minor azimuthal variations (NNW-SSE to NE-SW). Paleomagnetic declination data reveal ~ 13° ± 5° counterclockwise rotation since the Calabrian, supporting differential rotation across the Datça Peninsula and linking basin development to progressive opening of the Gökova Basin. Sedimentological evidence documents initial fluvio-lacustrine conditions, followed by a shallow-marine transgressive phase, with the upper marine deposits now > 100 m above present sea level, implying significant post 0.78 Ma uplift. Uplift and facies associations suggest dynamic topography and slab-edge processes associated with STEP faulting along the Pliny-Strabo Trenches controlled the evolution of the basin. Our results provide the most precise chronological framework to date for the Datça Graben, refine its structural development, and constrain the timing of Gökova Basin opening to post-1 Ma. The integration of magnetostratigraphic, geochronological, and structural datasets sheds light on the understanding of Aegean extensional dynamics and the interplay between regional rotation, uplift, and marine connectivity during the Quaternary.