## 2 Study Areas and Data  
### Study Area  
The research in this paper is focused on the area where the power transmission line project passes through Weinan City and Xi'an City, Shaanxi Province, China (Figure 1). It starts on the northwest side of Dongpoliwa Village, Baishui County, Weinan City, at the junction of Luochuan County and Baishui County, and ends at the Xi'an East Substation on the south side of Beizui Village, Lantian County, Xi'an City. The transmission line spans a length of 161 km. This segment of the transmission line is constructed as a double circuit on the same tower, passing through Baishui County, Chengcheng County, Pucheng County, Dali County, Linwei District and Huazhou District of Weinan City, and Lantian County of Xi'an City, a total of 2 districts and 5 counties. The overall terrain is high at both ends and low in the middle, sloping toward the Weihe River Valley. The north bank of the Weihe River is high in the north and low in the south, and the south bank of the Weihe River is low in the north and high in the south. The ground elevation is generally 340-1100 m [24]. The study area is located in the central basin region of Weinan City, within the stepped graben structure of the Weihe River. It is characterized by intense modern tectonic activity, with intersecting active faults showing significant vertical differential movement. The major faults include northeast-east-, east-west-, and north-northeast-trending faults. The exposed strata in the area primarily consist of the Mesozoic Triassic, Permian, Cenozoic Tertiary, and Quaternary periods. The Quaternary loess is extensively distributed, forming a thick cover over the underlying bedrock. The bedrock lithology is primarily composed of fluvial-lacustrine sandstones, limestones, mudstones, and interbedded shales [25; 26]. The regional geomorphic units are distributed from north to south, including the Luochuan Loess Tableland, low mountains and hills covered with loess (or with exposed bedrock), the Baishui River and Luo River valleys, the Weibei Loess Tableland, Weihe Plain, the Weinan Loess Tableland, the Loess Ridge and river valley depressions, and loess residual tabled. The overall terrain is high in the north and low in the south to the north of the Wei River and high in the south and low in the north to the south of the Wei River. It generally slopes toward the Wei River Valley. The boundaries of each geomorphic unit are obviously different, and the elevation difference along the line varies greatly. Controlled by the regional geological pattern of the Weihe River Basin, the topography around Weinan City is a typical \"two mountains and one river\" landform with high terrain in the north and south, decreasing and becoming flat toward the center of the basin. Taking the Wei River as the starting point of the Quaternary landform formation, the first-level terraces of the Wei River and its tributaries, the second- and third-level terraces covered with loess,the first and second-level loess tablelands, the piedmont alluvial plains with a certain slope, and the bedrock mountains are distributed in an orderly manner in the north and south directions. The climate under study belongs to the northern warm, temperate, subhumid climate zone, with cold winters, hot summers, significant temperature differences, and four distinct seasons. Spring is dry and windy, and the temperature rises sharply. Summer is hot and humid with rain. Autumn has a sudden drop in temperature and is short and windy. Winter has little rain and snow and is dry and cold for a long time. According to meteorological data from meteorological stations along the line, the average annual temperature in the area is 9.5-15.1 \({}^{\circ}\)C, the extreme maximum temperature is 34.6-42.9 \({}^{\circ}\)C, the extreme minimum temperature is \(-\)10.8-27.1 \({}^{\circ}\)C, the average annual rainfall is 513.9-710.4 mm, the average annual evaporation is 1347.0-1816.9 mm, and the maximum soil freezing depth is 29-93 cm [27].