A New Method for Isolating Elastic From Inelastic Deformation in Aquifer...

Chaussard, E., and T. G. Farr (2019), A New Method for Isolating Elastic From Inelastic Deformation in Aquifer Systems: Application to the San Joaquin Valley, CA, Geophys. Res. Lett., 46, doi:10.1029/2019GL084418.

Separating recoverable (elastic) from permanent (inelastic) deformation of aquifer systems is critical to develop sustainable pumping practices but remains a challenge because the preconsolidation stress is unknown. Previous works often assume that inelastic deformation occurs over years while elastic deformation is seasonal. This assumption may not hold for systems where groundwater extraction controls drawdowns and recharge because elastic deformation may not be exclusively seasonal (e.g., drought and recovery periods). Here we present an independent component analysis‐based method for extracting elastic aquifer properties without relying on sedimentary data or on curve fitting of seasonal signal. We applied this method to 2015–2019 Interferometric Synthetic Aperture Radar measurements of deformation in the San Joaquin Valley and show that elastic deformation is always present and captured by IC2 with both seasonal patterns and post drought recovery longer‐term deformation. Independent component analysis is the first method which enables isolating elastic deformation and properties even through periods that do not exhibit a clear seasonal signal.

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Earth Surface & Interior Program (ESI)