Earthquakes can affect underground water resources in several ways. The shaking and ground movement during an earthquake can cause changes in the permeability of the rock layers, leading to the potential for increased water flow or the creation of new pathways for water movement. However, earthquakes can also damage wells and underground infrastructure, leading to contamination or loss of access to groundwater. Additionally, seismic activity can trigger landslides or ground subsidence, altering the flow of underground water and potentially causing changes in water quality.