As a core and priority region of the Beijing-Tianjin Sandstorm Source Control Project, the mountainous area of northern Hebei plays a critical role in restraining desertification and ensuring the ecological security and sustainable development of the capital region. To reveal the ecosystem service flow mechanism of windbreak and sand fixation and support regional ecological sustainability, this study first used the Revised Wind Erosion Equation (RWEQ) to evaluate the spatial distribution of windbreak and sand-fixation services in northern Hebei mountainous area. Then, the HYSPLIT model was applied to simulate the spatial flow paths, identify the radiation scope, and quantify the radiation intensity of these ecosystem services. The results reflect the modeled patterns under given assumptions rather than fully verified actual ecosystem service supply. In 2024, the total amount of windbreak and sand-fixation service in the study area reached 10.3553 × 10⁶ tons. Sand-dust weather mainly occurred in spring and autumn, accounting for 39.23% and 33.46% of the total, respectively. The spatial flow paths were dominated by the northwest pathway (43.01%) and west pathway (38.17%). The total radiation scope of windbreak and sand-fixation services was 396.16 × 10⁴ km², among which 342.96 × 10⁴ km² was within the study area, accounting for 86.57%. The average service density was 21.06 kg/hm². The service density along flow paths decreased with increasing transport distance, while the radiation scope expanded with the increase in trajectory frequency. Spatially, the sand-fixation material density showed a circular decreasing trend from the center to the periphery of the study area. This study clarifies the flow characteristics and radiation benefits of windbreak and sand-fixation ecosystem services, which can provide a scientific basis for regional ecological protection, ecosystem service management, and the promotion of regional ecological sustainability.

Deep and ultra-deep hydrocarbon resources are of strategic importance for energy security. The pronounced ductility of deep reservoirs and faults makes hydraulic fracture propagation and induced seismicity mechanisms fundamentally different from those in conventional brittle reservoirs. This review systematically synthesizes recent theoretical, experimental, and numerical advances in hydraulic-fracturing-induced seismicity, covering triggering mechanisms, fault reactivation risk evaluation, and perspectives. A core distinction is identified: brittle faults exhibit instantaneous stick-slip rupture with high seismic frequency and significant magnitude, whereas ductile faults undergo stable aseismic creep and progressive slip, with long-term deformation prone to delayed large earthquakes—their nucleation shows unique mechanical responses including high stress drop, low rupture velocity, and low seismic radiation efficiency. Subsequently, four major challenges are distilled for risk evaluation systems: insufficient dynamic characterization of mechanical parameters in ductile reservoirs, lack of fracturing-control strategies adapted to ductile behavior, poor understanding of multi-scale slip transition mechanisms, and inadequacy of multi-field coupling models in capturing long-term delayed evolution. Traditional brittle-based risk frameworks cannot characterize the time-dependent slip and progressive reactivation of ductile faults, limiting their applicability to deep reservoirs. Future works are proposed, including refined characterization of mechanical parameters under high temperature and pressure, intelligent full-cycle hydrofracturing control, quantitative criteria for slip activation, and optimization of long-term multi-field coupling models. This study elucidates recent progress in hydrofracturing-induced seismicity mechanisms and quantitative risk assessment in ductile reservoirs, filling a gap in the conventional brittle-dominant research. It also provides theoretical support for seismic risk evaluation and early warning in deep fracturing operations, with significant implications for improving induced seismicity management and ensuring safe, efficient, and sustainable deep-resource development.