Coseismic responses of groundwater levels in the Three Gorges well-network to the Wenchuan M_S8.0 earthquake

We systematically analyze coseismic responses and post-seismic characteristics of groundwater levels in the Three Gorges well-network to the M_S8.0 Wenchuan earthquake on 12 May 2008. The results indicate that these characteristics differ among wells. On the conditions of similar borehole configurations, the differences are associated with geological structural sites of wells, burial types of aquifers monitored, and transmissivities of aquifer systems. We explored coseismic and post-seismic step-rise and step-drop mechanical mechanisms and their implication to earthquake prediction. We validated the inference that the residual step-rise zone is a possible earthquake risk zone based on recent seismic activity on the Xiannüshan fault in the area.