Abstract

Observation of earthquake-induced changes in well water levels provides an opportunity to study the effects of seismic activity on the groundwater system. In this study, we used data from a plain-scale well network in the alluvial Canterbury Plain of New Zealand's South Island to document sustained and complex changes in well water levels, following the 2010 Darfield earthquake. We interpret that the sustained increases in well water levels in the midstream area, as well as sustained decreases in the downstream area, resulted from decreases in plain-scale permeability. These decreases in permeability were caused by the consolidation of the liquefied sediments following the earthquake. These results may provide a better understanding of the effects of large earthquakes on groundwater systems and resources, especially in liquefaction areas.