Multitemporal geohazard susceptibility analysis can not only provide reliable results but can also help identify the differences in the mechanisms of different elements under different temporal and spatial backgrounds, so as to better accurately prevent and control geohazards. Here, we studied the 12 counties (cities) that were severely affected by the Wenchuan earthquake of 12 May 2008. Our study was divided into four time periods: 2008, 2009–2012, 2013, and 2014–2017. Common geohazards in the study area, such as landslides, collapses and debris flows, were taken into account. We constructed a geohazard susceptibility index evaluation system that included topography, geology, land cover, meteorology, hydrology, and human activities. Then we used a random forest model to study the changes in geohazard susceptibility during the Wenchuan earthquake, the following ten years, and its driving mechanisms. We had four main findings. (1) The susceptibility of geohazards from 2008 to 2017 gradually increased and their spatial distribution was significantly correlated with the main faults and rivers. (2) The Yingxiu-Beichuan Fault, the western section of the Jiangyou-Dujiangyan Fault, and the Minjiang and Fujiang rivers were highly susceptible to geohazards, and changes in geohazard susceptibility mainly occurred along the Pingwu-Qingchuan Fault, the eastern section of the Jiangyou-Dujiangyan Fault, and the riparian areas of the Mianyuan River, Zagunao River, Tongkou River, Baicao River, and other secondary rivers. (3) The relative contribution of topographic factors to geohazards in the four different periods was stable, geological factors slowly decreased, and meteorological and hydrological factors increased. In addition, the impact of land cover in 2008 was more significant than during other periods, and the impact of human activities had an upward trend from 2008 to 2017. (4) Elevation and slope had significant topographical effects, coupled with the geological environmental effects of engineering rock groups and faults, and river-derived effects, which resulted in a spatial aggregation of geohazard susceptibility. We attributed the dynamic changes in the areas that were highly susceptible to geohazards around the faults and rivers to the changes in the intensity of earthquakes and precipitation in different periods.

Analysis of the driving mechanism of wetland change can help identify the spatial differences in the mechanisms of different elements in order to better scientifically prevent and utilize wetlands. The Beijing-Tianjin-Hebei Plain (BTHP) was selected as the study area, and the dynamic degree model and change intensity index were utilized to examine the spatial and temporal changes of wetlands based on four periods of land use data. After establishing a wetland change evaluation system that included topography, geology, meteorological, and human activities, we utilized a random forest model to study the driving mechanism of wetland change from 1990–2020. Based on the developed zoning map, we then offered specific protection policies. We have four major findings: (1) the wetlands reduced significantly in the BTHP and underwent a change process from decreasing to increasing, and reservoirs and rivers, particularly along the Bohai Rim, were the primary determinants of wetland changes; (2) the impact of topographic factors such as elevation showed a significant gradient effect, the impact of geological factors such as hydrogeological division was low and indirect, the impact of meteorological factors was nonlinear, and the impact of anthropic factors was most significant and showed clear spatial directivity; (3) the urban expansion and agricultural reclamation had significant dominant effects, coupled with the topographical effects of elevation and slope, the geological environmental effects of surface subsidence and hydrogeological division, and the cumulative effects of temperature and precipitation, which resulted in the spatial change of wetlands; and (4) protecting wetland integrity, dynamic monitoring, restricting human activities, and establishing wetland buffer zones should be applied to the general area, natural factors area, anthropic factors area, and significant comprehensive area, respectively.