Close to the city of Huelva, SW Spain, and near the Atlantic Ocean, there is a phosphogypsum (PG) stack that accumulates 100 Mt of wastes and extends over 1000 ha. The stack lies directly over estuarine unconsolidated sediments with no protective layer in between. Here, we evaluate for the first time the structural stability of the PG stack, monitoring the deformation suffered by the salt-marsh basement. Through the web-based Geohazard Exploitation Platform (GEP) of the European Space Agency (ESA), a specific differential SAR interferometry (DInSAR) algorithm known as Parallel Small Baseline Subset (P-SBAS) has been used to process 279 ESA Sentinel-1 images acquired between October 2016 and June 2021. Resulting displacement maps and time-series curves reveal vertical displacements of up to 16 cm/year. This vertical motion has been associated to subsidence. In parallel with subsidence, horizontal movements > 2.5 cm/year have been also accounted and linked to talus destabilization. The analysis also demonstrates that the Huelva PG stack is vulnerable to adverse weather condition. The present study demonstrates that the InSAR-based methods are effective tools for monitoring the stability and ground motion of large waste stockpiles.

靠近西班牙西南部的韦尔瓦市和大西洋附近，有一个磷石膏 (PG) 堆，可累积 100 公吨的废物并延伸超过 1000 公顷。烟囱直接位于河口松散沉积物之上，中间没有保护层。在这里，我们首次评估了 PG 堆的结构稳定性，监测盐沼地下室遭受的变形。通过欧洲航天局 (ESA) 的基于网络的地质灾害勘探平台 (GEP)，一种称为并行小基线子集 (P-SBAS) 的特定差分 SAR 干涉测量 (DInSAR) 算法已被用于处理 279 ESA Sentinel-1在 2016 年 10 月至 2021 年 6 月之间获取的图像。生成的位移图和时间序列曲线显示垂直位移高达 16 厘米/年。这种垂直运动与沉降有关。在沉降的同时，水平运动 > 2.5 cm/年也被计算在内，并与距骨不稳定有关。分析还表明，Huelva PG 烟囱易受恶劣天气条件的影响。本研究表明，基于 InSAR 的方法是监测大型废物堆的稳定性和地面运动的有效工具。