Different Sensitivities of Earthquake‐Induced Water Level and Hydrogeological Property Variations in Two Aquifer Systems. Issue 5 (13th May 2021)

• Record Type: Journal Article
• Authors: Zhang, Hui; Shi, Zheming; Wang, Guangcai; Yan, Xin; Liu, Chenglong; Sun, Xiaolong; Ma, Yuchuan; Wen, Dongguang
• Is Part Of: Water resources research. Volume 57:Issue 5(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-05-13
• Subjects: Aquifer -- earthquake -- response sensitivity -- tidal analysis -- wavelet transform; Hydrology -- Periodicals; 333.91
• DOI: 10.1029/2020WR028217
• Languages: English
• ISSNs: 0043-1397

Abstract

Abstract: Determining the factors that control the sensitivity of aquifer responses to earthquakes may provide insight into the interaction between hydrogeological and tectonic processes in the shallow crustal zone. Such response sensitivity varies randomly at the spatial scale and its determining factors have not been evaluated quantitatively and are still under debate. In this paper, we analyze seismically induced water level changes and then infer aquifer permeability changes following multiple earthquakes in two long‐term groundwater‐monitoring wells. While earthquake‐related water level changes were observed in one well, the second was insensitive to seismic events. These different seismic responses provide a unique opportunity to identify factors that control earthquake‐related changes. Wavelet transform, coupled with water level responses to tidal forcing, provides a methodology for comparing pre‐ and post‐seismic responses to periodic behavior. These methods found aquifer hydrogeological properties (e.g., transmissivity, storativity, degree of confinement) to be functions of their local hydrogeologic and tectonic settings. Key factors that may affect hydrogeological responses include the seismic energy arriving around the well, the degree of aquifer confinement, and the well location relative to local faults. Such factors favor seismic shaking and fracture unclogging, thus determining the sensitivity of hydrogeological responses to earthquakes. These findings are useful for designing wells for monitoring earthquakes, understanding earthquake‐inducing mechanisms, evaluating underground waste repositories, and estimating hydrogeological parameters using inversion. Plain Language Summary: The sensitivity of hydrological response to earthquakes seems varies randomly at the spatial scale or differentially from one earthquake to another. Understanding the factor and mechanism that control such phenomena provide insight into the interaction between hydrogeological and tectonic processes in the shallow crustal. In this paper, by comparing the sensitivity of hydrogeological response to different earthquakes in two long‐term groundwater monitoring wells, we evaluated the potential causal factors (i.e., seismic factor and hydrogeological factors). We proposed that factors favor seismic shaking and fracture unclogging would determine the sensitivity of hydrogeological responses to earthquakes. The finding of this study would be benefit in the field of earthquake‐monitoring wells designing, seismic triggering, underground waste repositories, etc. Key Points: Aquifer hydrogeological properties are estimated from the tidal responses of water level and used to evaluate the sensitivity to earthquakes The responses may be controlled by the seismic energy around the well, the aquifer confinement, and the location relative to local faults Factors that favor seismic shaking and fracture unclogging determine the sensitivity of hydrogeological responses to earthquakes