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The Xieliupo landslide is a typical large-scale active landslide in Zhouqu, China, in the Pingding-Huama fault zone that has slid eight times since the beginning of the twentieth century. The landslide has caused catastrophic environmental, economic, and life losses in the area. In this study, combining the geomorphological field surveys, Unmanned Aerial Vehicle (UAV) mapping, interpretation of optical images, InSAR, and Cosi-Corr (Co-registration of Optically Sensed Images and Correlation) monitoring analysis, we conducted insights into the deformation kinematics of large Xieliupo landslide. The Xieliupo landslide has the characteristics of graded sub-activity with eight secondary landslides. The secondary landslides I and II in the upper parts are loess slide-flow with a moving pattern of creep–rip–push on the condition of steep gradient and the triggering of intense precipitation. The middle part was divided into two sides by a relatively stable ridge, where the loess rotational landslides III and collapse VI in the northern side are controlled by low-lying terrain in the valley, and the landslides IV and V are moderately active under the influence of steep gradient and compression from the landslides I and II. The secondary landslides VII and VIII in the toe are relatively slightly active with a gentle slope gradient influenced by road construction and Bailong River erosion. Time-series InSAR deformation from 2015 to 2020 revealed a close positive correlation between accelerating displacements and increasing precipitation. The deformation response characteristics of cascade collapse retreat and fluctuating acceleration of the Xieliupo landslide to heavy rainfall were revealed. The seismic activity is one probable factor contributing to the reactivated displacement of Xieliupo landslide. Notably, the intense rainfall on August 13, 2020, triggered the maximum displacement of 5.93 m in a sliding direction of 319° (NW) at secondary landslide II. This study significantly provides new insight into the deformation characteristics and kinematics of Xieliupo and reference for catastrophic landslide hazard mitigation. The proposed technique strategy can be used for analyzing similar large complex landslides in other mountainous regions. [ABSTRACT FROM AUTHOR]

The North Liuleng Shan Fault (NLSF) is one of the major active faults in the northern Shanxi Graben System (SGS) in North China. Although the fault has been investigated extensively in terms of late Quaternary activity, its active deformation pattern is still poorly characterized. In this study, we conducted a morphometric analysis of the fault using various geomorphic indices to assess the along-strike relative uplift rates, which include basin relief, slope, mountain front sinuosity (S mf), hypsometric integral (HI) and curves, valley floor width-to-height ratio (V f), asymmetry factor (A f), basin elongation ratio (R e), and normalized channel steepness indices (k sn). Our findings indicate that the central portion of the fault has experienced higher relative uplift rates than the southwestern and northeastern portions, as demonstrated by higher basin-averaged slopes and k sn values, and lower V f , R e , and S mf values. This spatial distribution pattern of relative uplift rates appears to correlate well with along-strike changes in the fault geometry and kinematics of the NLSF. We interpret the EW-striking, central portion of the NLSF as a releasing bend formed by the NE-striking, right-stepping, en-echelon southwestern and northeastern portions of the fault system, which are characterized by right-lateral oblique slip. Furthermore, the northeastward increase in HI values along with the regional basin evolution history suggest that the NLSF likely propagated from southwest to northeast. We propose that the southwestern portion of the fault most probably initiated earlier and that the central and northeastern portions formed later as extensional structures at the termini of the fault zone. Our findings contribute to a better understanding of the tectonics and genesis of the basin-and-range geomorphology in the northern SGS. • The relative uplift rate is highest in the central portion of the North Liuleng Shan Fault. • Oblique-slip releasing bend model explains the deformation along the North Liuleng Shan Fault. • The North Liuleng Shan Fault propagated gradually from southwest to northeast. [ABSTRACT FROM AUTHOR]

The Tan–Lu Fault Zone (TLFZ) is the largest continental‐scale strike‐slip fault zone in East China. It experienced a complex Meso‐Cenozoic deformation and controlled the development and evolution of the Bohai Bay Basin (BBB). Though its Mesozoic sinistral and Cenozoic dextral motions have been well documented, its strike‐slip transition history and mechanism from sinistral to dextral motions in the Early Paleogene remain poorly understood. To investigate these issues, we made a thorough analysis on the fault geometry and kinematics as well as the response of depocentre in the Early Paleogene of the sags adjacent to the TLFZ across the southeast BBB. The results show that the WNW‐/NW‐, E‐W‐, and ENE‐/NE‐trending extensional faults developed in the Early Paleogene of those sags share almost the same geometrical and kinematic features. Such features indicate that the TLFZ is sinistral in Ek3‐Ek2 depositional stage, extension dominated in Ek1 depositional stage, and dextral in Es4L depositional stage. Such strike‐slip transition of the TLFZ is a comprehensive effect of the plate events around the Eurasian Plate. The NNW‐directed subduction of the Pacific to the Eurasian plates triggers the sinistral motion of the TLFZ during 65–55 Ma, but this sinistral motion is terminated by the far‐field effect of the NNE‐directed India–Eurasia collision initiating at 55 Ma. Then, the kinematic adjustment of the Pacific Plate from NNW to WNW breaks the stress balance exerted on the TLFZ by the subduction of the Pacific to Eurasian plates and the India–Eurasia collision and makes it turn into dextral motion gradually during 48–42 Ma. [ABSTRACT FROM AUTHOR]

The Yilan-Yitong Fault Zone (YYFZ), which is composed of two nearly parallel branches with a spacing of 5–30 km and a length of ∼1100 km, is considered to be the key branch of the Tancheng-Lujiang Fault Zone (TLFZ) in NE China. It was traditionally believed that the YYFZ experienced weak activity or was inactive during the Late Quaternary, without the capability to generate strong earthquakes (M ≥ 7), based on the absence of typical outcrops and large historical or instrumental earthquakes (M > 6). However, our paleoseismic study shows that the YYFZ is the primary seismotectonic structure (M ≥ 7) that poses significant earthquake threats to NE China. The synthesis of data collected from geologic investigations, geomorphic mapping, trench logging and the dating of samples indicates that the YYFZ is an active structure that has undergone segmented strong tectonic deformation since the Late Quaternary with a characteristic assemblage of landforms, including linear scarps and troughs, offset or deflected streams, linear sag ponds, small horsts and grabens. The latest ruptures of the YYFZ migrated from previous boundary faults into the basin interior, forming a left-stepping en echelon pattern in plain view, and the kinematics of these events in the Late Quaternary were dominated by reverse dextral slipping. Multi-segment cluster faulting might have occurred during three cluster periods, i.e., ∼34750–35812 a BP, ∼21700–22640 a BP, and ∼4000 a BP-present, which implies that the recurrence interval of large earthquakes along the YYFZ may be as long as tens of thousands of years. [ABSTRACT FROM AUTHOR]

The main brittle faults in the Jiangsu part of the Tan-Lu Fault Zone, East China, are, from east to west, faults F 1 , F 5 , F 2 , F 3 , and F 4 . The details of their Quaternary activity remain controversial. We present structural, depositional, topographical, and geochronological evidence that indicates widespread fault activity during the Quaternary. Our fieldwork revealed that faults F 1 , F 5 , F 2 , and F 3 cut Quaternary sediments. Each fault produces a narrow gouge belt in the Quaternary sediments and incohesive fault rocks consisting of gouge, unconsolidated breccia and cataclastic belts in the bedrock. With the exception of dextral faulting along the northern part of the fault F 1 , the main Quaternary faults show evidence of thrusting with a minor dextral component. Analysis of a large amount of fault-slip data demonstrates that ENE–WSW compression was responsible for the Quaternary faulting. Our OSL dating results, combined with observed changes in Quaternary sediment thicknesses, indicate that except for Holocene activity on the northern part of fault F 1 , and probable Quaternary activity on the northern part of fault F 4 , the most recent period of activity on the main faults in the Jiangsu part of the Tan-Lu Fault Zone was the late Pleistocene. These inferences are consistent with the absence of M ⩾ 4.0 earthquakes along the fault zone. Fault displacement data and Quaternary sedimentation suggest that Quaternary activity was more intense in the late Pleistocene, and that faults F 2 and F 5 were the most intensely active. Our field investigation shows that faults F 1 –F 4 originated from the reactivation of Cretaceous graben-boundary faults whereas fault F 5, with its varied dip directions, was derived from the reactivation of antithetic normal faults associated with the boundary faults in the eastern graben. [ABSTRACT FROM AUTHOR]

The middle segment of the NNE–SSW-striking Tan-Lu Fault Zone (TLFZ) crosses the Bohai Bay in East China. This fault zone is a large seismically active belt that was responsible for the 1969 M (magnitude) 7.4 Bohai earthquake. However, the geometry, kinematics, and detailed characteristics of the most recent Quaternary seismic activity along the TLFZ in the Bohai Bay area are debated, primarily as the fault crops out below sea level in this area. Here, we present the results of a series of seismic profiles that enable the identification of Quaternary activity along the TLFZ within the Bohai Bay area. These data indicate that the Quaternary TLFZ crops out over a wide area of the Bohai Bay and is dominated by two main faults, both of which dip steeply to the west. Each of these two main faults consists of several left-stepping en-echelon faults. Quaternary activity along the TLFZ was generally focused along pre-existing Paleogene–Neogene faults. The seismic profiles, combined with the distribution of earthquakes in this area, demonstrate that the TLFZ in the southern and central areas of the Bohai Bay was last active during the Holocene, whereas the last movements along the faults in the northern Bohai Bay area range from late Pleistocene in the south to early–middle Pleistocene and the end of the Neogene in the north. The seismic profiles show both normal and reverse offset of the base of the Quaternary sediments by the Tan-Lu faults, although the normal offset predominates. Anticlines developed in Quaternary sediments occur close to the Quaternary Tan-Lu faults, and the TLFZ is also associated with an angular unconformity between Holocene and Pleistocene sediments. It is likely that the TLFZ was dominated by reverse dextral slip during the Holocene, whereas all of the Quaternary faulting before this involved alternating reverse and normal dextral slip. Oblique extension is most likely responsible for the normal dextral slip along the TLFZ, whereas focal mechanisms, GPS (global positioning system) data, and in situ stress measurements all suggest that ENE–WSW compression led to the reverse dextral faulting associated with numerous recent earthquakes in the Bohai Bay area. [ABSTRACT FROM AUTHOR]

Early Mesozoic geodynamic and tectonic relations between different blocks in East China remain controversial. The Subei-South Yellow Sea Basin (SB-SYSB) is located at the junction of different blocks and tectonic zones, including the North China Block (NCB), South China Block (SCB), Sulu Orogen and Tan-Lu Fault Zone (TLFZ). Therefore, the basin is a key location for understanding the regional geologic evolution of East China. Here, we present the geometry and kinematics of opposite thrust systems (OTSs) under the SB-SYSB based on seismic profiles, well data, magnetic reversion data and field observations. The OTSs are composed of two sets of thrust systems with opposite senses of motion: the northern top-to-the-southeast thrust system (N-TS) and southern top-to-the-northwest thrust system (S-TS). According to the structural styles, the N-TS and S-TS can be divided into the root, middle and frontal belts. The strikes of thrusts show a shift from NNE to N E - ENE and then to nearly E-W from west to east. The OTSs were suggested to have formed during the end of the middle Triassic to the middle Jurassic, and its deformation intensity decreased from west to east and from the root belt to the frontal belt. Combining these lines of evidence with published geochronological data for the Dabie-Sulu Orogen and other structural elements in East China, we provide a comprehensive synthesis and propose a new tectonic model to explain the early Mesozoic geodynamic and tectonic relations in East China. We emphasize the following points: (1) The Sulu Orogen might extend to the Northern Depression in the offshore SYSB and be bounded by the North Fault of the Central Massif to the south, indicating that the Sulu Orogen is significantly wider than stated in previous studies. (2) The N-TS was driven by the subduction of the YZB and the exhumation of the Sulu HP–UHP metamorphic rocks. In contrast, the S-TS was probably controlled by the orogenic uplift of the Jiangnan Orogen. (3) The dragging of the thrusts in the SB-SYSB and adjacent areas indicates that the sinistral motion of the TLFZ was coeval with the formation of the OTSs and was likely caused by the clockwise rotation of the SCB. (4) Finally, this clockwise rotation probably triggered intense corner compression between the Sulu Orogen, TLFZ and East Marginal Fault of the Yellow Sea, resulting in a genetic relation among the Sulu Orogen, the SCB, the Korean Peninsula and the Xu-Huai Belt. • The OTSs were controlled by subduction of the SCB, the exhumation of the Sulu Orogen and the uplift of the Jiangnan Orogen; • The Sulu Orogen might extend to the Northern Depression in the SYSB and be bounded by the North Fault of the Central Massif; • The TLFZ was coeval with the formation of the OTSs; • We proposed a model to illustrate the relationship among the Sulu Orogen, the SCB, the Korean Peninsula and the Xu-Huai Belt. [ABSTRACT FROM AUTHOR]

Abstract: The Tan–Lu Fault Zone (TLFZ) extends in a NNE–SSW direction for more than 2000 km in Eastern China. It has been considered either as a major sinistral strike-slip fault, as a suture zone or as a normal fault. We have conducted a structural analysis of the southern segment of this fault zone (STLFZ) in the Anhui Province. The ages (Triassic to Palaeocene) of the formations affected by the faults have been re-appraised taking into account recent stratigraphical studies to better constraint the ages of the successive stages of the kinematics of the STLFZ. Subsequently, the kinematics of the faults is presented in terms of strain/stress fields by inversion of the striated fault set data. Finally, the data are discussed in the light of the results obtained by previous workers. We propose the following history of the STLFZ kinematics during the Mesozoic. At the time of collision, a ∼NNE orientated Tan–Lu margin probably connected two margins located north of the Dabie and Sulu collision belts. During the Middle–Late Triassic, the SCB has been obliquely subducted below the NCB along this margin which has acted as a compressional transfer zone between the Dabie and Sulu continental subduction zones. The STLFZ has been initiated during the Early Jurassic and has acted as a sinistral transform fault during the Jurassic, following which the NCB/SCB collision stopped. A ∼NW-trending extension related to metamorphic domes was active during the basal Early Cretaceous (∼135–130 Ma); it has been followed by a NW–SE compression and a NE–SW tension during the middle–late Early Cretaceous (∼127 to ∼105 Ma, possibly ∼95 Ma); at that time the TLFZ was a sinistral transcurrent fault within the eastern part of the Asian continent. During the Late Cretaceous–Palaeocene, the STLFZ was a normal fault zone under a WNW–ESE tension. [Copyright &y& Elsevier]

Structural style along the active, NW-striking, right-slip Karakoram fault in western Tibet ranges from transpression in the north (37° to 34°N) to transtension in the south (34° to 32°N). This transition in structural style occurs at a 27-km-wide bend in the fault. Our new neotectonic mapping has documented the long-asserted structural linkage between the ENE-striking Gozha–Longmu Co fault system and the similarly oriented active, leftslip Altyn Tagh fault to the northeast. This mapping also indicated that the restraining bend in the Karakoram fault is located where this fault intersects the Gozha-Longmu Co extension of the Altyn Tagh fault to the west. Additional observations from remotely sensed imagery suggest that the total left-separation along the Gozha-Longmu Co fault system is 25-32 km. We use the new neotectonic mapping and published slip rates to develop a simple kinematic model for the main active faults in western Tibet to explore the genetic relationship between slip along the Gozha- Longmu Co fault system and the geometric and kinematic evolution of the Karakoram fault. This model combines published geodetic and Quaternary slip rates with the known fault geometries and demonstrates that the transition from transpression to transtension along the Karakoram fault can be explained by differential motions between the NW Himalaya, the Tianshuihai terrane, and the Tibetan Plateau. These motions produce bending and transtension along the central and southern Karakoram, respectively, and movement of the Tibetan Plateau at a rate of 6–13 mm/ yr toward the east-southeast relative to the Pamirs. We also fi nd that the Gozha–Longmu Co fault system likely initiated between 10 and 3 Ma to accumulate 25–32 km of total left separation. We suggest that the Gozha-Longmu Co fault system formed during late Miocene to Pliocene structural reorganization of the southwestern Altyn Tagh and southern Karakoram fault systems to allow eastward migration of the Tibetan Plateau and northward migration of the Pamir syntaxis. [ABSTRACT FROM AUTHOR]

The collision of the Indian subcontinent with Asia drives the growth and evolution of the greater Tibetan Plateau region. Fault slip rates resulting from the relative motion between crustal blocks can provide a kinematic description of the distribution of present-day deformation. I construct a three-dimensional, regional-scale elastic block model of the India-Asia collision zone that is consistent with geodetic observations of interseismic deformation, mapped fault system geometry, historical seismicity, and the mechanics of the earthquake cycle. This mechanical model of the elastic upper crust yields a set of kinematically consistent fault slip rates and block motions that may serve to constrain dynamic models of continental crustal dynamics. [ABSTRACT FROM AUTHOR]

Integrated geological-geophysical methods have been used to depict the geometric characteristics and kinematic evolution of the Shunbei 5 (SB5) and adjacent Shunbei1 (SB1) strike-slip faults in the central Tarim Basin, China. Geometric evidence for strike-slip faulting includes the occurrence of positive and negative flower structures in stepover zones, oblique secondary splay faults, en echelon folds, and adjacent secondary faults. The multi-humped along-strike and along-dip displacement variations of the SB5 fault provide insights into the initial segmentation, interaction and polycyclic growth of the fault zones both in plan and section views: The SB5 fault initiated as an apparent "X-type" conjugate pure shear fault system in the north and a simple shear fault system in the south respectively. At depth (mainly in Cambrian to Middle Ordovician rocks), the northern and southern parts of the SB5 fault exhibit a typical dextral strike-slip architecture consisting of multiple fault segments connected via transpressional push-up or transtensional pull-apart stepovers or bends. The southern part has a linear, narrow sinistral ridge system. At shallower depths (in Upper Ordovician to Middle Devonian rocks), the lower subvertical faults propagated upwards as en echelon normal faults in the north, and as a two-phase, partitioned system consisting of boundary grabens and en echelon normal faults that dissected the early-formed border grabens in the south. With progressive deformation, the northern and southern parts of the SB5 fault reactivated and transferred into one large, sinistral fault in Upper Devonian to Permian rocks. Four major tectonic phases matching the kinematic evolutions of regional fault systems and uplifts in the study region, have also been recognized in the Middle Ordovician to Cretaceous. The pull-apart stepover and single fault zones developed in Middle Ordovician rocks are favorable fracture-related reservoirs. • Temporospatial distributions of the SB5 fault have been interpreted. • Along-strike and along-dip displacements have been investigated to analyze fault segmentation and polycyclic evolution. • Four major strike-slip movements that occurred from the Middle Ordovician to Permian have been recognized. • The SB5 fault initiated as different strike-slip systems, then reactivated as one large fault with the same sinistral motion. [ABSTRACT FROM AUTHOR]

• Field observations demonstrate the geometry and kinematics of Seertengshan Piedmont Fault. • Both planar and curved normal faults characterize the outcropping fault zones. • Sequential development of normal faults resulted in rotation of fault blocks. • Similarity of geometry and kinematic behaviors exists at multiple spatial scales. Although rotation of fault blocks during seismic and long-term periods has long been recognized in extensional tectonic regimes, the geometry and kinematic behaviors of normal faults at outcrop scale have scarcely been investigated in sufficient detail. In this study, combining with the analysis of high-resolution topography acquired by small unmanned aerial vehicle (sUAV) using the structure-from-motion (SfM) technique, we present the results of our field observations on the structural characteristics of the Seertengshan Piedmont Fault (SPF), a major active normal fault bounding the northern margin of the Hetao Graben, North China. Although previous studies have reported the recent tectonic activity of this fault including timing of most recent earthquake, average slip rate and repeat time of paleo-earthquakes, few of them have focused on geometric patterns of the outcropping fault zones, which provide excellent outcrop-scale examples to investigating geometry and kinematics of active normal faults. Besides the observed prominent fault scarps indicative of recent tectonic activity along the SPF, outcrop observations indicate that in some cases both planar and curved normal faults are developed, forming complex fault zones. Sequential development of normal faults may have rotated the early-formed fault blocks, resulting in shallowly dipping faults and highly tilted strata. Collectively, structural similarities probably exit among normal faults at multiple spatial scales. We suggest that the results of this study are also helpful for a better understanding of structural development and evolution in other actively extending areas. [ABSTRACT FROM AUTHOR]

Gaoqing-pingnan fault zone characterized as "S" plane shape is the boundary ofwestern Dongying depression. The western Dongying depression includes twosecondary negative tectonic units: Huagou and Boxing sub-depression. The study areaunderwent several phases of extension in the early Cenozonic, but the extensionaldirection mainly deflects along nearly N-S. According to the changes of the faultstrike, Gaoqing-pingnan fault zone can be divided into three segments: Huagou(E-W), Pingnan (NNE), and Binnan (NEE). By analysis of 3D seismic interpretationresults and geometry model, we find that the attitude and combination type of thethree segments are markedly different although they are influenced by the sameextension stages. On attitude, Huagou and Binnan segments paralleling to earlyCenozoic structural strike of Dongying depression are characterized by slowerdip angles, but the Pingnan segment which parallels to strike of Tanlu fault zoneis characterized by steeper dip angles. On combination types of faults, Huagouand Binnan segments mainly develop extensional types; Binnan segment not onlydevelop extensional types like formers, but also develop strike-slip types such as halfa flower and horsetail faults in vertical profile, feathery and en echelon faults inplane. In order to explain the structural differences, further study on kinematics wasdone with seismic coherence cube and Strata thickness data of wells. The timeslices of coherence cube and seismic sections indicate that nearshore fans whichdevelop in hanging wall of Pingnan segment in the Es4-Es1 migrate along the NWdirection. What is more important, Strata isopachous map reveals the same kinematicsregularity that the depocenter of Boxing sub-depression also migrate along the NNEdirection in Es4 -Es1. In contrast, both of migratory direction of fans and depocenter inHuagou sub-depression are perpendicular to the strike of Huagou segment during Es4-Es1. In conclusion, the structural evolution of Pingnan segment is controlled bythe oblique extension, but the Huagou and Binnan segments are controlled by theperpendicular extension in the early Cenozonic. This study offers a case study onunderstanding the evolution of a segmented normal fault zone in rift basin of eastern China. [ABSTRACT FROM AUTHOR]