234-1 A Physics-Informed GNSS–InSAR–GRACE Framework for Water Resources & Hazards Monitoring

Session: Advance Ground Surface Modeling for Hydrological and Environmental Applications

Presenting Author:

Authors:

Abstract:

Ground‐surface deformation encodes signals of surface and subsurface hydrologic change, but converting those signals into management-relevant estimates of water storage and dynamics remains difficult because multiple processes act together. The dominant hydrology-induced mechanisms, crustal elastic loading and poroelastic aquifer deformation, vary with geology and pumping hotspots, carrying different hazard implications. Clarifying how these mechanisms contribute to observed vertical land motion (VLM) can support both water-resources decisions and subsidence risk assessments.

I illustrate hydrologically driven deformation patterns across selected applications worldwide, with a focus on highly populated urban areas. In the Central Valley, California, I show how vertical land motion (VLM) from the Global Navigation Satellite System (GNSS) and Interferometric Synthetic Aperture Radar (InSAR) is useful for monitoring the health of confined aquifers and for predicting groundwater storage (GWS) changes that agree with the Gravity Recovery and Climate Experiment and its follow-on (GRACE/FO) mission. In Mexico City, we investigate high-resolution InSAR to demonstrate that not only poroelastic aquifer mechanics, but also elastic-loading-related uplift, can be monitored with InSAR. Around Lake Mead, I show that even modest declines in surface reservoir storage can be detected through observations of crustal loading and hint at GWS loss beneath. The challenge, however, is that the deformation signals have opposite signs and overlap; a clean separation is difficult because of temporal colocation and uncertainty in geophysical parameters.

Finally, I present a physics-informed, multi-sensor geodetic framework that uses elastic loading and poroelastic displacements, both observed at high resolution via GNSS and InSAR, together with mass change from GRACE/FO as a regional constraint, to estimate TWS and GWS variations. Rather than partitioning deformation a priori, gravity and deformation signals are co-analyzed within a shared (hybrid) inverse model. In California’s Central Valley during the 2019-2021 drought, the model yields TWS/GWS change fields that are dynamically and mechanically consistent across sensors. I discuss the limitations of existing models and ongoing work aimed at resolving them. Together, these results demonstrate how joint geophysical modeling with multi-sensor geodesy advances ground-surface modeling for hydrological and environmental applications—quantifying drought impacts, supporting water-cycle studies, and delineating subsidence-related infrastructure risk—while providing a scalable pathway to couple geodetic constraints with groundwater models for climate-impact assessment, and evaluation of strategies such as managed aquifer recharge.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-9065

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