A RESPONSE OF THE "RESERVOIR-WELL" SYSTEM TO DISTANT EARTHQUAKES

The results of joint processing of hydrogeological and seismic data obtained at the Large-Scale Research Facilities "Mid-Latitude Geophysical Observation Complex "Mikhnevo" for a 12-year observation period are presented in the article. Responses of the "reservoir-well" system to the passage of seismic waves from distant earthquakes with magnitudes of 6.3-9.0, recorded at the epicentral distances from 1863 to 16507 km, have been identified in the database. Maximum values of groundwater level variations and ground velocity under seismic impact have been determined. The power-law dependence of the levels amplitudes of confined and weakly confined aquifers on the maximum vertical ground velocity has been established. A spectral analysis of 6-hour intervals (3 hours before and 3 hours after earthquakes) of seismic and hydrogeological data was performed. The frequencies corresponding to the maximum values of ground velocity and groundwater level variations were determined in the normalized spectra. The intervals within which the extremes of the hydrogeological responses are traced at background values of the ground velocity are identified in the low-frequency range. The amplitude-frequency characteristics of the "reservoir-well" systems differ under seismic impacts at epicentral distances up to 4901 km. The responses of the systems to earthquakes at epicentral distances of 11024-14026 km are similar.

1. Batukhtin I.V., Besedina A.N., Gorbunova E.M., Petukhova S.M., 2020. Dynamic Deformation of Fluid-Saturated Collectors by Precision Hydrogeological Monitoring at "Mikhnevo" Geophysical Observatory. Processes in Geomedia 4 (26), 867‒876 (in Russian)

2. Besedina A., Vinogradov E., Gorbunova E., Svintsov I., 2016. Chilen Earthquakes: Aquifer Responses at the Russian Platform. Pure and Applied Geophysics 173, 321‒730. http://dx.doi.org/10.1007/s00024-016-1256-5.

3. Brodsky E.E., Roeloffs E., Woodcock D., Gall I., Manga M., 2003. A Mechanism for Sustained Groundwater Pressure Changes Induced by Distant Earthquakes. Journal of Geophysical Research: Solid Earth 108 (B8). http://dx.doi.org/10.1029/2002JB002321.

4. Gorbunova E.M., Besedina, A.N., Vinogradov E.A., 2018. Dynamics of Deformation in the Fluid-Saturated Collector from Precision Monitoring of Groundwater Level. In: Dynamic Processes in Geospheres. Collection of Scientific Papers of the Institute of Mining RAS. Iss. 10. Grafiteks, Moscow, p. 74‒83 (in Russian). https://doi.org/10.26006/IDG.2018.10.20178.

5. Kopylova G.N., Boldina S.V., 2020. Effects of Seismic Waves in Water Level Changes in a Well: Empirical Data and Models. Izvestiya, Physics of the Solid Earth 56, 530‒549. https://doi.org/10.1134/S1069351320030039.

6. Shalev E., Kurzon I., Doan M.-L., Lyakhovsky V., 2016. Sustained Water-Level Changes Caused by Damage and Compaction Induced by Teleseismic Earthquakes. Journal of Geophysical Research: Solid Earth 121 (7), 4943–4954. https://doi.org/10.1002/2016JB013068.

7. Shi Z., Wang G., Manga M., Wang C.-Y., 2015. Mechanism of Co-Seismic Water Level Change Following Four Great Earthquakes – Insights from Co-Seismic Responses throughout the Chinese Mainland. Earth and Planetary Science Letters 430, 66–74. http://dx.doi.org/10.1016/j.epsl.2015.08.012.

8. Shin D.C-F., Wu Y.-M., Chang C.-H., 2013. Significant Coherence for Groundwater and Rayleigh Waves: Evidence in Spectral Response of Groundwater Level in Taiwan Using 2011 Tohoku Earthquake, Japan. Journal of Hydrology 486, 57‒70. http://dx.doi.org/10.1016/j.jhydrol.2013.01.013.

9. Sun X., Wang G., Yang X., 2015. Coseismic Response of Water Level in Changping Well, China, to the Mw 9.0 Tohoku Earthquake. Journal of Hydrology 531 (3), 1028–1039. http://dx.doi.org/10.1016/j.jhydrol.2015.11.005.

10. Sun X., Xiang Y., Shi Z., 2018. Estimating the Hydraulic Parameters of a Confined Aquifer Based on the Response of Groundwater Levels to Seismic Rayleigh Waves. Geophysical Journal International 213 (2), 919–930. http://dx.doi.org/10.1093/gji/ggy036.

11. Xiang Y., Sun X., Gao X., 2019. Different Coseismic Groundwater Level Changes in Two Adjacent Wells in a Fault-Intersected Aquifer System. Journal of Hydrology 578, 124123. https://doi.org/10.1016/j.jhydrol.2019.124123.