Large Earthquake Reshapes the Groundwater Flow System: Insight From the Water‐Level Response to Earth Tides and Atmospheric Pressure in a Deep Well

Abstract

Quantitative evaluation of earthquake‐induced permeability changes is important for understanding key geological processes, such as advective transport of heat and solute and the generation of elevated fluid pressure. Many studies have independently documented permeability changes in either an aquifer or an aquitard, but the effects of an earthquake on both the aquifer and aquitard of the same aquifer system are still poorly understood. In this study, we use the well water‐level response to earth tides and atmospheric pressure to study the changes in hydraulic properties in an aquifer and an overlying confining layer in Beijing, China, following the 11 March 2011 Tohoku earthquake in Japan. Our results show that both the tidal response amplitude and the phase shift increased and that the phase shift changed from negative to positive after the earthquake. We identified increased permeability in both the aquifer and aquitard by the barometric response function method. The horizontal transmissivity of the aquifer increased by a factor of 6, and the vertical diffusivity of the aquitard doubled.

Changes in Physical Properties of Inland Streamwaters Induced by Earth and Atmospheric Tides

“…Overall, the properties of the geologic strata are very important in the behavior of groundwater tides [38]. Methods to assess the influence of the local geology and environment on groundwater tide characteristics, such as phase shifts, range from analyzing special conditions [39] to applying various mathematical techniques. The decomposition of water-level time series containing tidal oscillations might be a useful tool for simplifying the data analysis [40].…”

Estimation of Groundwater Evapotranspiration Using Diurnal Groundwater Level Fluctuations under Three Vegetation Covers at the Hinterland of the Badain Jaran Desert

“…e GWL series are easily distinguished from each other except the cycles induced by atmospheric pressure and evapotranspiration, as the two have similar fluctuant shapes. Atmospheric pressure effects can also occur in unconfined aquifers typically mirroring each other [47][48][49]. e diurnal cycles induced by atmospheric pressure and evapotranspiration are both continuous time series.…”

Earthquake Hydrogeology

“…Tidal analysis thus offers a biased sampling of the crustbiased to deep, low-compressibility rocks far from coastlines. Extensive networks of wells exist globally, including the network hosting the monitoring well considered by Zhang et al (2019). The research 10.1029/2019WR025341…”

“…The ongoing increase in quantitative analysis owes both to the growing availability of suitable seismic and hydrologic data and to a realization that earthquake responses can provide new insights into hydrologic and mechanical properties of the crust. Zhang et al (2019) use coseismic and postseismic changes in the water-level response to Earth tides and atmospheric pressure to estimate earthquake-caused increases in aquifer and aquitard permeabilities. To the best of our knowledge, this is the first time that coseismic aquifer and aquitard responses have been separately distinguished, as well as the first application of wavelet analysis to this problem.…”