The coefficients in Eqs. (1) and (2) indicate the magnitude of
groundwater level change under the applied force. They appear
as the co-seismic step change of a groundwater level anomaly.
The terms in brackets in Eqs. (1) and (2) indicate the recovery
behavior. Based on the linear poroelastic theory, the groundwater
level must recover to its original position under a constant external
force. In this study, only the co-seismic step anomaly is analyzed.
Therefore, with t?0 in Eqs. (1) and (2), the terms in each pair of
brackets become one and the co-seismic responses of Dh can be
respectively obtained as