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Spatiotemporal Analysis of Land Subsidence in the Koohdasht Plain Using the SBAS-InSAR Technique and Sentinel-1 Images
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Ava Osman pour  , Peyman Heidarian * , Seyed Davoud Mohammadi , Somayeh Fathtabar Firoozjaei , Ali Movahedian , Habib Salehi |
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Abstract: (9 Views) |
Abstract
Objective: In recent years, the Koohdasht Plain has experienced significant land subsidence due to intensive groundwater exploitation and its distinctive geological characteristics. This study aims to monitor, quantify, and analyze the spatiotemporal rate and pattern of land subsidence across the plain over two time periods (2018–2023 and 2015–2024), to compare the results of these intervals, and to examine surface manifestations of ground deformation.
Methods: The SBAS-InSAR (Small Baseline Subset-Interferometric Synthetic Aperture Radar) technique was applied in conjunction with regional hydrogeological and geological data. Ascending and descending Sentinel-1 SAR images were processed using the LiCSBAS software package. After atmospheric phase correction using GACOS data, ground surface displacement time series were derived for five-year and nine-year intervals. Annual subsidence rates were then calculated from the SBAS results, and the spatial distribution of subsidence across the plain was evaluated through integration with hydrogeological and geological datasets.
Results: The maximum annual subsidence rate was estimated at approximately 59.9 mm yr⁻¹ for the five-year period and 71.9 mm yr⁻¹ for the nine-year period. Given that the nine-year interval encompasses a longer observation window, its results were adopted as the primary basis for interpretation. Within this period, the years 2015–2016 and 2017–2018 exhibit the highest cumulative subsidence. These intervals show clear correspondence with groundwater-level declines recorded in hydrographs of the selected Omour-Ashayer and Sari piezometers, indicating a direct relationship between groundwater depletion and subsidence rates. The spatial distribution pattern reveals that the highest subsidence values are concentrated in the southern, southeastern, and southwestern sectors of Koohdasht City, coinciding with significant groundwater drawdown and thicker fine-grained alluvial deposits.
Conclusion: Overall, within the Koohdasht aquifer, the annual variation in subsidence rate demonstrates a decreasing trend from east to west, while persistent subsidence continues in the westernmost sector. This pattern suggests a reduced capacity of the aquifer to recover its initial conditions and an increasing vulnerability to sustained groundwater extraction. Furthermore, the findings confirm the decisive role of hydrogeological and lithological factors in controlling land subsidence in the Koohdasht Plain and highlight the effectiveness of advanced remote sensing approaches—particularly the SBAS-InSAR technique—for accurate and continuous monitoring of geological hazards. |
Article number: 5 |
| Keywords: Time-series interferometry, Remote sensing, Land subsidence, Koohdasht Plain, Geological hazards |
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Type of Study: Research |
Subject:
Special
Received: 2026/02/15 | Accepted: 2026/02/15 | Published: 2026/02/15
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