An integrated approach [field, Interferometric Synthetic Aperture Radar (InSAR), hydrogeology, geodesy, and spatial analysis] was adopted to identify the nature, intensity, and spatial distribution of deformational features (sinkholes, fissures, differential settling) reported over fossil aquifers in arid lands, their controlling factors, and possible remedies. The Lower Mega Aquifer System (area 2 × 106 km2) in central and northern Arabia was used as a test site. Findings suggest that excessive groundwater extraction from the fossil aquifer is the main cause of deformation: (1) deformational features correlated spatially and/or temporally with increased agricultural development and groundwater extraction, and with a decline in water levels and groundwater storage (− 3.7 ± 0.6 km3/year); (2) earthquake events (years 1985–2016; magnitude 1–5) are largely (65% of reported earthquakes) shallow (1–5 km) and increased from 1 event/year in the early 1980s (extraction 1 km3/year), up to 13 events/year in the 1990s (average annual extraction > 6.4 km3). Results indicate that faults played a role in localizing deformation given that deformational sites and InSAR-based high subsidence rates (− 4 to − 15 mm/year) were largely found within, but not outside of, NW–SE-trending grabens bound by the Kahf fault system. Findings from the analysis of Gravity Recovery and Climate Experiment solutions indicate that sustainable extraction could be attained if groundwater extraction was reduced by 3.5–4 km3/year. This study provides replicable and cost-effective methodologies for optimum utilization of fossil aquifers and for minimizing deformation associated with their use.

中文翻译：

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使用地球物理和遥感数据评估含水层枯竭和相关土地变形

采用综合方法 [现场、干涉合成孔径雷达 (InSAR)、水文地质学、大地测量学和空间分析] 来确定报告的化石含水层上变形特征（天坑、裂缝、差异沉降）的性质、强度和空间分布干旱土地、其控制因素和可能的补救措施。阿拉伯中部和北部的下巨型含水层系统（面积 2 × 106 平方公里）被用作试验场。研究结果表明，从化石含水层过度抽取地下水是变形的主要原因：(1) 变形特征在空间和/或时间上与农业发展和地下水抽取的增加以及水位和地下水储存量的下降相关 (- 3.7 ± 0.6 平方公里/年）；（2）地震事件（1985-2016年；1-5 级）大部分（65% 的报告地震）是浅层地震（1-5 公里），从 1980 年代初期的每年 1 次事件（抽取 1 平方公里/年）增加到 1990 年代的每年 13 次事件（平均年开采量 > 6.4 平方公里）。结果表明，断层在定位变形方面发挥了作用，因为变形位点和基于 InSAR 的高沉降率（- 4 至 - 15 毫米/年）主要存在于 NW-SE 向地堑内，但不在其边界的 NW-SE 向地堑之外。 Kahf 故障系统。重力恢复和气候实验解决方案的分析结果表明，如果地下水开采量每年减少 3.5-4 平方公里，就可以实现可持续开采。这项研究为优化利用化石含水层和最大限度地减少与其使用相关的变形提供了可复制且具有成本效益的方法。