Groundwater Responses to Earth Tides: Evaluation of Analytical Solutions Using Numerical Simulation

Harmonic Earth tide components in well water levels have been used to estimate hydraulic and geomechanical subsurface properties. However, the robustness of various methods based on analytical solutions has not established. First, we review theory examine latest solution relate tides. Second, develop verify a novel numerical model coupling hydraulics geomechanics strains. Third, assess conditions over depth for range realistic Fourth, simulate level response strains within 2D poroelastic layered aquifer system confined by 100 m thick aquitard. We find that non-linear inversion match two observations (amplitudes phases) multiple unknown parameters is sensible initial guess. reveal undrained, are necessary be valid. This occurs dominant M2 frequency at depths >50 requires specific storage constant strain Sϵ ≥ 10−6 m−1, conductivity aquitard kl ≤ 5 ⋅ 10−5 ms−1 ka 10−4 ms−1. further illustrate valid unconsolidated systems, whereas consolidated systems require additional consideration Biot modulus. Overall, priori knowledge supports interpretation groundwater response. Our results improve understanding effect tides its