Physics-Based Relationship for Pore Pressure and Vertical Stress Monitoring Using Seismic Velocity Variations

Abstract

Previous studies examining the relationship between the groundwater table and seismic velocities have been guided by empirical relationships only. Here, we develop a physics-based model relating fluctuations in groundwater table and pore pressure with seismic velocity variations through changes in effective stress. This model justifies the use of seismic velocity variations for monitoring of the pore pressure. Using a subset of the Groningen seismic network, near-surface velocity changes are estimated over a four-year period, using passive image interferometry. The same velocity changes are predicted by applying the newly derived theory to pressure-head recordings. It is demonstrated that the theory provides a close match of the observed seismic velocity changes.

Advanced monitoring of tailings dam performance using seismic noise and stress models

“…We developed an effective approach to apply effective stress principles 46 to model dV s /V s in the near surface. An alternative approach 47 relies on physics-based modeling to demonstrate that changes in shear wave velocities are primarily caused by fluctuations in effective stress. Modeled changes in seismic surface wave velocity were obtained using relationships applicable to deeper structures in the order of hundreds of meters, using a spectral element method 48 .…”

The Seismic Signature of California's Earthquakes, Droughts, and Floods

“…Recent work by Fokker et al. (2021) suggests that pore pressure sensitivity may be shallower than shear‐wave sensitivity, therefore our assumed deepest sensitivity is likely an overestimate. For all models, t i is the best fitting delay between mean daily temperature and dv/v , in days.…”

“…This porosity value was chosen as a lower bound for sedimentary rocks, and an upper bound for effective porosity in fractured bedrock (Ehrenberg & Nadeau, 2005;Heath, 1998;Worthington, 2022). Recent work by Fokker et al (2021) suggests that pore pressure sensitivity may be shallower than shear-wave sensitivity, therefore our assumed deepest sensitivity is likely an overestimate. For all models, t i is the best fitting delay between mean daily temperature and dv/v, in days.…”

Probing environmental and tectonic changes underneath Ciudad de México with the urban seismic field

“…Several previous studies have applied detailed physics-based models to dc c , usually focusing on a small number of selected stations (Tsai, 2011;Richter et al, 2014;Lecocq et al, 2017;Fokker et al, 2021;Illien et al, 2021Illien et al, , 2022 or time series (Rodríguez Tribaldos and Ajo-Franklin, 2021). Previous array-wide analyses have mostly focused on empirical transfer functions between hydrologic and meteorologic parameters and observed dc c (e.g.…”

“…Under the assumption that the coda of the resulting waveforms is predominantly sensitive to changes in the elastic medium, one can measure subtle relative advances and delays in the current waveform compared to the reference, which are approximately linearly related to relative velocity changes dv v . Using this technique reveals that seismic velocity varies with groundwater level (Sens-Schönfelder and Wegler, 2006;Lecocq et al, 2017;Fokker et al, 2021;Rodríguez Tribaldos and Ajo-Franklin, 2021), precipitation, soil moisture and snow load (Obermann et al, 2014;Voisin et al, 2016;Wang et al, 2017;Donaldson et al, 2019;Andajani et al, 2020;Mordret et al, 2020;Feng et al, 2021;Illien et al, 2021), ground temperature (Richter et al, 2014), thawing of the permafrost (Ajo-Franklin et al, 2017;James et al, 2019;Lindner et al, 2021), and even centimeter-scale layers of soil freezing (Steinmann et al, 2021). Droughts can induce longer-term changes of seismic velocity (Clements and Denolle, 2018;Mao et al, 2021), as can soil compaction (Taira et al, 2018).…”