Determining the main controlling factors of earthquake-triggered geohazards is a prerequisite for studying earthquake geohazards and post-disaster emergency response. By studying these factors, the geomorphic and geological factors controlling the nature, condition, and distribution of earthquake-induced geohazards can be analyzed. Such insights facilitate earthquake disaster prediction and emergency response planning. The authors combined field investigations and spatial data analysis to examine geohazards induced by seismic events, examining 10 earthquakes including the Wenchuan, Yushu, Lushan events, to elucidate the main control factors of seismic geohazard. The authors observed that seismic geohazard occurrence is usually affected by many factors, among which active nature of the seismogenic fault, seismic peak ground acceleration (PGA), topographic slope and geomorphic height differences, and distance from the fault zone and river system are the most important. Compared with strike-slip earthquakes, thrust earthquakes induce more high-altitude and high-speed remote landslides, which can cause great harm. Slopes of 0–40° are prone to secondary seismic geohazards, which are mainly concentrated 0–6 km from the river system. Secondary geohazards are not only related to seismogenic fault but also influenced by the associated faults in the earthquake area. The maximum seismic PGA and secondary seismic geohazard number are positively correlated, and the horizontal and vertical ground motions play leading and promoting roles in secondary geohazard formation, respectively. Through our research, the spatial distribution of seismic geohazards is predicted, providing a basis for the formulation of emergency response plans following disasters.

Blindly developing shallow geothermal energy (SGE) may lead to difficulties in reinjection, a low coefficient of performance (COP), and the waste of funds. In order to avoid these problems and improve development efficiency, it is necessary to scientifically conduct a development suitability evaluation and classify the suitability levels before development. This article takes Chengde City, Hebei Province, China as an example and constructs an evaluation index system based on the analysis of regional basic conditions. The Analytic Hierarchy Process (AHP) was used to calculate the constant weight. A Fuzzy C-means Clustering (FCM) analysis was used to determine the critical value of evaluation index classification and the interval threshold of variable weights. The parameters of the variable-weight model were calculated using the method of model backcalculation. Based on the constructed variable-weight model, the suitability of SGE development for groundwater sources in the study area was evaluated, and it was divided into five levels: most suitable area, suitable area, relatively suitable area, less suitable area, and unsuitable area. Through a verification analysis of engineering examples and a comparison with the evaluation results under traditional constant-weight models, it was found that the evaluation results based on variable weight theory have better data discreteness and a higher accuracy. Research has shown that variable-weight models can adjust the weight of each index based on its state value. Through this study, the accuracy of the suitability evaluation for regional SGE development can be improved. This can provide a certain reference for the suitability evaluation of SGE development in other regions.

In recent years, China has invested substantial funds in ecological restoration, achieving significant accomplishments. The forest coverage rate in the Chengde Bashang area, located in the transitional zone between the monsoon and non-monsoon regions, has now reached 82%. However, the area has also encountered a series of environmental issues, including lake shrinkage, soil salinization, and large-scale die-offs of planted forests. Whether the forests in this region can achieve sustainable development in the future, and whether ecological restoration should prioritize tree planting or grass cultivation, are critical questions that require attention. By studying the historical vegetation dynamics in afforested areas, we can better understand the relationship between climatic environmental changes and vegetation, providing baseline data for future ecological restoration. This study utilized AMS ¹⁴C dates to establish a chronological framework for the core and employed pollen to investigate vegetation dynamics over the past 5000 years in the artificial Larix Mill. forest area. The vegetation and environmental history of this core can be divided into three zones: Zone 1 (5100–4100 a B.P.): vegetation was dominated by pine and spores, with low herbaceous pollen content. Zone 2 (4100–1400 a B.P.): vegetation was primarily herbaceous. Zone 3 (1400 a B.P.–present): arboreal pollen content increased slightly, but herbaceous plants remained dominant. This period included the warm–dry Medieval Warm Period (1400–900 a B.P.), the cold–humid Little Ice Age (900–300 a B.P.), and the recent 300 years of anthropogenic disturbance. Notably, the large-scale afforestation efforts in recent decades are clearly reflected in the profile. A comparative analysis of records from the monsoon–non-monsoon transition zone reveals that, except for Angulinao Lake, other records were dominated by herbaceous vegetation over the past 2000 years. Additionally, the Mu Us Sandy Land, Hunshandake Sandy Land, Hulunbuir Sandy Land, and Horqin Sandy Land in China have experienced aeolian sand accumulation over the same period. Given the anticipated warming–desiccation trend, phytoremediation strategies should favor xerophytic shrubs and herbaceous over monospecific forest plantations.