Satellite InSAR survey of structurally-controlled land subsidence due to groundwater exploitation in the Aguascalientes Valley, Mexico

REMOTE SENSING OF ENVIRONMENT

卷:254

Article

Cigna, Francesca¹  Tapete, Deodato¹ 

[1] Italian Space Agcy ASI, Via Politecn Snc, I-00133 Rome, Italy

关键词: Land subsidence;    Surface faulting;    Mexico;    InSAR;    Sentinel-1;    Aquifer depletion;    Groundwater pumping;    SAR;    SBAS;    Angular distortion;   

DOI  :  10.1016/j.rse.2020.112254

来源: Elsevier

【 摘 要 】

To address increasing water demands in expanding cities, many aquifers in Mexico are overexploited and deplete. The resulting land subsidence often combines with ground faulting/fracturing and damage to infrastructure. This study provides the longest Synthetic Aperture Radar (SAR) survey ever undertaken for the Aguascalientes Valley, aimed to constrain its structurally-controlled subsidence process and the induced risk. 275 ERS-1/2 1996-2002, ENVISAT 2003-2010 and Sentinel-1 2014-2020 C-band SAR images are processed with change detection, differential Interferometric SAR (InSAR) and Small Baseline Subset (SBAS) methods. Aguascalientes notably expanded over the last four decades, as revealed by Seasat 1978 L-band SAR, Landsat 1985-2010 and Sentinel-2 2020 optical imagery. The observed subsidence pattern involves alluvial/fluvial deposits within the N-S trending graben. Maximum settlement rates are -14 cm/year in 1996, -10 cm/year in 2000-2010 and over -12 cm/year in 2015-2020. An acceleration (-0.70 cm/year(2)) is recorded in 2015-2020 close to recently developed industrial plants and housing districts. Satellite estimates agree with in-situ observations, static GPS surveying and continuous GPS monitoring data. Rough correlation is found with piezometric level drop rates, whereas aquifer thickness plays a stronger role in the subsidence process. While these outcomes align with the existing literature, this InSAR survey: (i) unveils previously unknown E-W deformation affecting two N-S oriented bands within the valley, with up to similar to +/- 3 cm/year in 2015-2020 towards its center; (ii) identifies zones of sagging and hogging with horizontal strain (epsilon) of up to 0.05-0.1%; (iii) retrieves differential rates reaching 6-8 cm/year and angular distortions (beta) of 1/500 along the Oriente fault; and (iv) investigates the statistical distribution of, beta across field surveyed faults and fissures, and marks areas with potentially yetunmapped ground discontinuities. A new surface faulting risk matrix embedding beta and epsilon is therefore proposed to estimate subsidence impact on properties and population. Given its scale-dependency, the risk assessment provides a lower bound to the percentage of urban areas at risk within the Aguascalientes state: at least 2% of the urban areas were at high and very high risk in 2003-2010 (involving similar to 12,000 properties and similar to 39,000 inhabitants), but this increased to 6% in 2015-2020 (similar to 25,600 properties, similar to 85,200 inhabitants). The evidence of a subsidence process evolving spatially and temporally highlights the need for continuous updating of hazard information.

【 授权许可】

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