# Correlation between Soil Moisture Change and Geological Disasters in E'bian Area (Sichuan, China)
## 2 Materials and Methods  
### Study Area  
The western Sichuan Basin, located in the western part of Sichuan Province and on the eastern edge of the Qinghai-Tibet Plateau, is characterized by complex terrain and diverse geological conditions, making it one of the regions in China where geological disasters frequently occur. The topographical features of E'bian Yi Autonomous County are mainly manifested as folds, faults, and ductile shear zones. These structural features have a significant impact on the occurrence and development of geological disasters, making this a frequent area of geological disasters in the western Sichuan Basin. E'bian is located in Leshan City, upstream of the Yangtze River. The terrain of this area is mainly composed of mountains, hills, and plains. Mountains account for most of the total area of the county, mainly distributed in the western and northern parts of the county. The hilly area is mainly distributed in the middle of the county, while the plain is mainly distributed in the eastern part of the county. Due to the influence of the E'meishan Fault Zone, the E'bian region is one of the areas with frequent seismic activity. The most prominent fault in this area is the E'bian Fault in Leshan, which is one of the main faults causing seismic activity. In addition to the E'bian Fault, there are also several minor geological faults distributed in the region, which also have an impact on the geological structure (Figure 1). Figure 1: Geological map of the study area. The stratigraphic geological development of the E'bian region reflects a complex geological evolution spanning multiple periods of geological history, primarily including the Paleozoic, Mesozoic, and Cenozoic eras. During the Paleozoic era, the E'bian region was submerged under marine environments, accumulating abundant marine sedimentary rocks such as limestone and shale. Granite is widely distributed in the E'bian region, particularly in mountainous and hilly areas. These granites formed under high-temperature and high-pressure conditions deep within the Earth's crust, undergoing prolonged cooling and crystallization, resulting in their hard and durable characteristics, commonly observed in outcrops and mountainous terrain. During the Mesozoic era, the E'bian region experienced tectonic movements and magmatic activity, giving rise to various igneous and metamorphic rocks. These include granites, graisses, schists, and quartzites. In sedimentary basins and river valleys of the E'bian region, sandstones and shales are commonly found, formed through prolonged sedimentation and compaction, recording the region's geological history and environmental changes. Since the Cenozoic era, the E'bian region has undergone tectonic uplift and erosion, shaping the present-day landscape. Sedimentary processes have continued during this period, resulting in the formation of new sedimentary rock layers in environments such as rivers and lakes. These rocks contain rich mineral resources, such as coal, iron ore, and copper ore [16; 17; 18]. The E'bian area belongs to a subtropical humid climate, with four distinct seasons, abundant rainfall, and sufficient sunlight. At the same time, the water system in this area is developed, with many rivers passing through, the most important of which is the Minjiang River, an important tributary of the Yangtze River. These rivers provide abundant water resources for the ecological environment of this area, so the vegetation in this area is rich and diverse. However, with the development of urbanization and the increasing demand for mineral resources, human activities have played a leading role in the destruction of the ecological environment. Excessive deforestation may lead to a decline in forest coverage, a reduction in biodiversity, an intensification of soil erosion, and a decrease in water source protection capabilities.