The Shanxi Rift System (SRS) is a prominent intracontinental rift in eastern Eurasia. However, its tectonic origin remains enigmatic, as the timing of rift initiation and its subsequent evolution is not well constrained. To evaluate the cooling history of rift flanks, we present joint apatite fission track (n = 15) and apatite (U‐Th‐Sm)/He (n = 62) thermochronological study across the Huo Shan and the Zhongtiao Shan in the central and southern SRS, respectively. Inverse modeling of the thermochronological data yields two episodes of enhanced exhumation during the Cenozoic. Both ranges record rapid cooling circa 50‐35 Ma, coeval with a phase of widespread rifting across entire North China. Data from the Zhongtiao Shan record renewed cooling from ∼8 Ma to the present, following a protracted near‐isothermal condition. Considering the SRS in the context of plate reconstructions, we propose that the Eocene rift initiation is triggered by the subduction of the trench‐parallel Izanagi‐Pacific mid‐ocean ridge followed by subduction of the Pacific plate. Tectonic quiescence along the Shanxi rift during Oligocene and Miocene time reflects slow thermal subsidence as the Pacific subduction regime was established. In late Miocene, faults associated with the SRS were reactivated in dextral transtension linked to fault systems that extend outward from the northeastern Tibetan Plateau. This kinematic reorganization implies a fundamental change in force balance throughout North China. Overall, our results reflect the changing influence of tectonic regimes along the eastern Eurasian plate boundary and intracontinental deformation associated with the India‐Eurasia collision.

A magnitude (Mw) 7.4 Maduo earthquake occurred on 22 May 2021 in the northern Qinghai-Tibet Plateau, with predominantly left-lateral strike-slip faulting and a component of normal faulting within the Bayan Har Block. The co-seismic surface rupture extended in a NWW direction for ~160 km with a complicated geometry along a poorly known young fault: the Jiangcuo Fault. The main surface rupture propagated bilaterally from the epicenter and terminated eastward in horsetail splays. The main rupture can be divided into five segments with two rupture gaps. Field surveys and detailed mapping revealed that the co-seismic surface ruptures were characterized by a series of left-lateral offsets, en echelon tensional cracks and fissures, compressional mole tracks, and widespread sand liquefication. The observed co-seismic left-lateral displacements ranged from 0.2 m to ~2.6 m, while the vertical displacements ranged from 0.1 m to ~1.5 m, much lower than the InSAR inverse slip maximum of 2–6 m. Based on the comprehensive analysis of the causative fault geometry and the tectonic structure of the northern Bayan Har Block, this study suggests that the multiple NWW trending sub-faults, including the Jiangcuo Fault, developed from the East Kunlun fault northeast of the Bayan Har Block could be regarded as the sub-faults of the East Kunlun Fault system, constituting a broad and dispersive northern boundary of the Block, controlling the inner strain distribution and deformation.

Induced earthquakes are becoming a significant issue. Several destructive induced earthquakes (⁠ $Ms$ ≥5.0) have occurred in shale gas fields located at the southwestern Sichuan basin, China, in the recent years. Specifically, two moderate earthquakes with magnitudes of $Ms$ 5.4 (occurred on 8 September 2019) and 5.2 (occurred on 18 December 2019) exceeded the largest earthquake ever recorded in the Weiyuan. It remains unclear which seismogenic faults were responsible for the two moderate events due to insufficient knowledge of the subsurface structure and contradictory hypocenter depths obtained from different seismological methods. In this study, mainshock locations, focal mechanisms, and precise relocations of microseismicity were used to map the 3D geometry of the seismogenic fault. The result shows that the two moderate earthquakes occurred on the same fault. High‐resolution seismic reflection profiles indicate several preexisting faults at various depths and a potential seismogenic fault. No large‐scale faults are identified in the sedimentary cover above the Cambrian at the shallow centroid depth of these earthquakes. However, the seismic reflectors show phase discontinuous feature, indicating the existence of preexisting faults in the basement. A preexisting fault in the basement is consistent with a seismogenic fault that may have induced the two moderate earthquakes. Our study suggests that poroelastic stress propagation is likely responsible for the basement fault reactivation. The rupture on a stressed basement fault was triggered and produced two moderate earthquakes in a short period during hydraulic fracturing. The previous strategy of avoiding direct injection of fluids into preexisting faults to reduce seismic risk in operation region is not enough to avoid the possibility of the coupled poroelastic stress triggering deep fault rupture. We need to reevaluate the potential seismic risk of shale gas development in Weiyuan, the southern Sichuan basin shale gas field considering the preexisting faults in sedimentary and in basement and the effect of the fully coupled poroelastic stress field.