基于PS-InSAR技术的武威市地面沉降时空变化特征

武威市位于甘肃省中部，是一座典型的农业城市，分布有大量农业耕地。由于土壤疏松，地面容易受到降水和地下水的影响，易发生地面沉降地质灾害对居民的生产、生活造成不利影响。本文利用2017年2月至2022年12月的Sentinel-1A数据，通过PS-InSAR技术提取了武威市的地面沉降监测数据，包括视线向形变速率和累积形变量。对形变场的时空分布特征进行了详细分析，并引入Mogi模型反演地下深部变形范围。最后，结合研究区的降水数据和GRACE重力卫星获取到由陆地水负荷引起的地表形变数据，并对研究区的沉降成因进行了初步分析。结果表明，研究区存在两个主要沉降区，其中主沉降区A的最大累积沉降量达到-290.9 mm，视线向形变速率为-52.0 mm/a；主沉降区B的沉降量达到-178.1 mm，视线向形变速率为-43.8 mm/a。地表沉降呈现周期性变化，且向东南方向逐步扩展，与降水和地下水变化特征相似。通过Mogi模型反演，得出了主沉降区的地下影响范围（半径）和深度，其中主沉降区A为40.96 m和133.67 m，主沉降区B为38.60 m和140.78 m。按季节划分统计形变数据，结果表明，由于研究区所属干旱区，自然降水无法对地面沉降产生显著影响，而农耕时大量地下水的抽取才是导致区域地面沉降的主要原因。

Temporal and spatial characteristics of ground subsidence in Wuwei City based on PS-InSAR technology

Wuwei City, located in the central part of Gansu Province, is a typical agricultural city with extensive agricultural farmland. Due to loose soil, the ground is susceptible to the influence of precipitation and groundwater, leading to subsidence that adversely affects the production and livelihood of residents. In this study, we utilized Sentinel-1A data from February 2017 to December 2022 and employed PS-InSAR technology to extract ground subsidence monitoring data for Wuwei City. This data includes line-of-sight deformation rates and cumulative deformation values. A detailed analysis of the spatiotemporal distribution characteristics of the deformation field was conducted, and the Mogi model was introduced to invert the deep-seated deformation range. Finally, in conjunction with precipitation data for the study area and GRACE satellite-derived information on land water storage changes, an initial analysis of the causes of subsidence in the study area was performed. The research results indicate the presence of two main subsidence areas in the study region. In subsidence area A, the maximum cumulative subsidence reached -290.9 mm, with a line-of-sight deformation rate of -52.0 mm/a. In subsidence area B, the subsidence amounted to -178.1 mm, with a line-of-sight deformation rate of -43.8 mm/a. Ground subsidence exhibits periodic variations, gradually expanding towards the southeast, showing similarities with the characteristics of precipitation and groundwater changes. Through Mogi model inversion, the underground influence range(radius)and depth of the main subsidence areas were determined, with subsidence area A having values of 40.96 m and 133.67 m, and subsidence area B having values of 38.60 m and 140.78 m. Seasonal division and statistical analysis of deformation data revealed that, due to the study area being in an arid region, natural precipitation had a limited impact on ground subsidence, while the substantial extraction of groundwater during agricultural activities emerged as the primary cause of regional ground subsidence.