Calculation of the BK_uvalue from the well-aquifer system response to seismic waves

The characteristics of groundwater oscillation and persistent variation caused by seismic waves have extensively been discussed. However, the response of groundwater level to S and Love waves and the correction of well storage effect in open self-flowing wells have not been quantified. Based on the theory of linear pore elasticity in the ideal porous elastic medium, the mathematical expressions between pore pressure variation and bulk strain and deviation strain in the well-aquifer system are investigated. By comparing the measured groundwater level variation of the Changping groundwater observation well caused by M_w9.0 earthquake in Japan on March 11, 2011 with the calculated values obtained by curve fitting, the influencing factors of pore pressure are confirmed and the linear elastic coefficient BK_u of the rock is solved. Compared with the tidal analysis, it is verified that the elastic characteristics of the rock derived from the seismic method represent the actual aquifer characteristics. In addition, the correlation coefficient shows that the groundwater level oscillation is affected by both the volumetric and the deviatoric dynamic strains.