Evaluation of groundwater-caused deformation patterns in a metropolitan area using time series InSAR and retrieval of vertical and east-west displacement: a case study in Taipei City
Journal
Geomatics, Natural Hazards and Risk
Journal Volume
15
Journal Issue
1
ISSN
1947-5705
1947-5713
Date Issued
2024-07-12
Author(s)
Abstract
This study explores the influences of groundwater fluctuations in an urban area which lead to long-term ground surface subsidence using a time-series synthetic aperture radar interferometry (InSAR) technique. Unlike most prior studies that only focus on line-of-sight (LOS) deformation, assume negligible horizontal movements, and quantify InSAR-groundwater relationship on a sparse temporal scale, this study utilized the Persistent Scatterers InSAR (PS-InSAR) technique to extract east-west and vertical displacement by decomposing Sentinel-1 ascending and descending datasets spanning from 2018 to 2022. Additionally, an approach was proposed to effectively quantify the relationship between changes in groundwater levels and vertical displacement on a daily basis. The results underwent robust validation against ground-based leveling surveys, revealing a satisfactory NRMSE of 1.06 mm/yr. Furthermore, founded on the estimated vertical displacement, three districts within Taipei City (e.g. Wugu, Xinzhuang, and Taishan) were identified as subsidence hotspots, with maximum vertical deformation rates reaching −11.77 mm/yr. Eventually, the correlation analysis and quantification between vertical displacement and daily groundwater data underscore long-term groundwater fluctuations as the primary cause of subsidence. These findings, derived from InSAR-based 2D displacements, have proven valuable in understanding groundwater-caused ground subsidence hazards in urban areas and empowering relevant stakeholders to set out corresponding adaptation and mitigation measures.
Subjects
2D displacement analysis
geodetic leveling survey
groundwater depletion
groundwater well observation
Persistent scatterers InSAR (PS-InSAR)
sentinel-1A
urban aquifer-land surface dynamics
urban land subsidence monitoring
Publisher
Informa UK Limited
Type
journal article