Characterizing the Transition to Irrecoverable Deformation in the
Subsurface with an InSAR Multi-Sensor Time Series Analysis
Abstract
Tracking the onset of inelastic (permanent) deformation is critical to
quantifying the stress experienced by an aquifer system so that the
effects of current groundwater extraction practices are put in the
context of the sedimentary and geological histories of a region.
However, the pre-consolidation stress is rarely known due to the lack of
multi-decadal ground-based data. In this paper, we propose a new
approach to track the onset and spatial evolution of inelastic
deformation based on a 2003-2020 multi-sensor Interferometric Synthetic
Aperture Radar time series analysis. Our study reveals that in central
Iran, many locations that used to experience elastic (recoverable)
deformation just a few years ago, are now deforming inelastically,
leading to irreversible lowering of the ground surface and irreversible
loss of aquifer storage. Lithologic data reveals that the total
thickness of the drained clay layers controls the extent and timing of
the observed inelastic deformation, while groundwater data confirms that
the multi-decadal lowering of groundwater levels is driving the
long-term compaction. These results highlight that we are now at or near
a tipping point in time between sustainability and permanent damage to
our underground water resources, emphasizing the fact that current
decisions have the potential to change the natural resources landscape
permanently.