The application of satellite differential SAR interferometry-derived ground displacements in hydrogeology

Abstract

The application of satellite differential synthetic aperture radar (SAR) interferometry, principally coherent (InSAR) and to a lesser extent, persistent-scatterer (PSI) techniques to hydrogeologic studies has improved capabilities to map, monitor, analyze, and simulate groundwater flow, aquifer-system compaction and land subsidence. A number of investigations over the previous decade show how the spatially detailed images of ground displacements measured with InSAR have advanced hydrogeologic understanding, especially when a time series of images is used in conjunction with histories of changes in water levels and management practices. Important advances include: (1) identifying structural or lithostratigraphic boundaries (e.g. faults or transitional facies) of groundwater flow and deformation; (2) defining the material and hydraulic heterogeneity of deforming aquifer-systems; (3) estimating system properties (e.g. storage coefficients and hydraulic conductivities); and (4) constraining numerical models of groundwater flow, aquifer-system compaction, and land subsidence. As a component of an integrated approach to hydrogeologic monitoring and characterization of unconsolidated alluvial groundwater basins differential SAR interferometry contributes unique information that can facilitate improved management of groundwater resources.

Multi-temporal mapping of land subsidence at basin scale exploiting Persistent Scatterer Interferometry: case study of Gioia Tauro plain (Italy)

“…This approach uses long stacks of radar data and analyzes the signals backscattered from the observed scenes to retrieve estimates of the displacements that have occurred between different acquisitions, by distinguishing the phase signals related to ground motions from those due to topography, atmosphere, and noise (e.g., Ferretti et al, 2001). PSI techniques are highly suitable to monitor urban areas affected by land subsidence and related hazards, and in the last decade have demonstrated their potential for the analysis at both regional and local scales of very slow displacements (e.g., Cigna et al, 2012;Galloway & Hoffmann, 2007;Herrera et al, 2009), for which conventional investigation would not have provided comparable cost-efficiency, coverage and density of measures, and precision.…”

Interpolation of GPS and Geological Data Using InSAR Deformation Maps: Method and Application to Land Subsidence in the Alto Guadalentín Aquifer (SE Spain)

“…Over the past two decades, Interferometric Synthetic Aperture Radar (InSAR) techniques have revolutionized the study of ground displacements associated with different phenomena, including aquifer system compaction and ground subsidence [8,9]. InSAR has been used to detect and monitor many areas of subsidence produced by groundwater exploitation [10][11][12], deduce aquifer hydraulic properties [13][14][15] and estimate hydraulic head evolution [16].…”

Polarimetric Calibration of the Ku-Band Advanced Polarimetric Radar Interferometer

“…The ability to measure the line-of-sight component of movements over large areas makes it suitable for many applications. Some examples are the estimation of subsidence rate associated with temporal changes in the water table of aquifers, oil and gas extraction, deep mining and tunnel excavation [5]- [7], the monitoring of inflation/deflation connected to volcanic activity [8], the mapping of ice sheet and glacier motion [9], [10] , the observation of instable slopes in rugged natural terrain and open pit mines [11], [12] and the measurement of seismic displacements [13], [14]. Fully polarimetric radar data provides additional information on the scattering mechanism within each resolution cell, which is employed for classification of the surface cover [15], [16], to extract geophysical parameters such as moisture content [17], to estimate the orientation of the vegetation canopy [18] or the height of fresh snow [19].…”