Danqi Jiang’s research while affiliated with Hohai University and other places

This study investigates the geometry, kinematics, and interaction of thin- and thick-skinned tectonics at the western Sichuan Basin adjacent to the eastern margin of the Tibetan Plateau. A two-level detachment system, comprising a shallow Triassic and basal Precambrian detachment, was identified. Three-dimensional (3-D) structural modeling was applied to demonstrate the geometry of the shallow detachment that developed in the Sichuan foreland basin. The shallow detachment forming material is an evaporite sequence deposited in the Middle Triassic, which was subsequently buried beneath the foreland basin and later subsided rapidly during the flexural loading process during the Late Triassic. In the Cenozoic, this set of evaporite rocks developed into an effective shallow detachment, transferring geologic slip from the Longmen Shan range front to the Sichuan Basin. The structure of this shallow detachment exhibits an asymmetrical characteristic, with its deepest location consistent with the Mesozoic foreland depression. This relationship indicates that foreland subsidence in the Late Mesozoic is the main factor controlling the geometry of the detachment. In the southern Cenozoic foreland basin, the development of thrust faults above the Precambrian basal detachment resulted in a local deformation and uplift of the shallow detachment, resulting in a lower basal slope (0.5°–1°) of the sedimentary basin taper and a high internal distribution. In contrast, the sedimentary basin taper in the north has a high basal slope that mainly translates along the shallow detachment, lacking thrusting-related structures. This study reveals that the pre-existing stratigraphic architecture of the sedimentary basin can influence the subsequent structural deformation of the foreland basin. This has important implications for other foreland basins with multistage crustal shortening processes.

Human activity-induced earthquakes are emerging as a global issue, and revealing its underlying mechanisms is essential for earthquake hazard mitigation and energy development. We investigated the relationship between the seismotectonic model and seismic sequences from moderate Mw 4.3 and Mw 5.2 earthquakes that occurred in February and September 2019, respectively, in the Weiyuan anticline of Sichuan basin, China. We found that the Mw 5.2 earthquake ruptured a back thrust of structural wedges and released most aftershocks near the wedge tip. However, the two foreshocks of the Mw 4.3 earthquake sequence occurred in hydrofractured Silurian shale at depth of 2.5–3 km, and the mainshock ruptured the overlying oblique tear fault at a depth of ∼1 km. Hydraulic fracturing in the sedimentary cover of this block may induce earthquakes through fluid pressure diffusion in the Silurian shale and through poroelastic effects on back thrusts within structural wedges, respectively. We assessed the hazard potential of four seismic sources in the Weiyuan block and suggest it is critical to conduct a coupled flow-geomechanics assessment and management on induced seismicity and related cascading effects in the densely inhabited and seismically active Sichuan basin.

Along‐strike structural linkage and interaction between faults is common in various compressional settings worldwide. Understanding the kinematic history of fault interaction processes can provide important constraints on the geometry and evolution of the lateral growth of segmented faults in the fold‐and‐thrust belts, which are important to seismic hazard assessment and hydrocarbon trap development. In this paper, we study lateral structural geometry (fault displacement and horizon shortening) of thrust fault linkages and interactions along the Qiongxi anticline in the western Sichuan foreland basin, China, using a high‐resolution 3D seismic reflection dataset. Seismic interpretation suggests that the Qiongxi anticline can be related to three west‐dipping, hard‐linked thrust fault segments that sole onto a regional shallow detachment. Results reveal that the lateral linkage of fault segments limited their development, affecting the along‐strike fault displacement distributions. A deficit between shortening and displacement is observed to increase in linkage zones where complex structural processes occur, such as fault surface bifurcation and secondary faulting, demonstrating the effect of fault linkage process on structural deformation within a thrust array. The distribution of the geometrical characteristics shows thrust fault development in the area can be described by both the isolated fault model and the coherent fault model. Our measurements show that new fault surfaces bifurcate from the main thrust ramp, which influences both strain distribution in the relay zone and along‐strike fault slip distribution. This work fully describes the geometric and kinematic characteristics of lateral thrust fault linkage, and may provide insights into seismic interpretation strategies in other complex fault transfer zones.