Hydrological Changes Induced by Distant Earthquakes at the Lujiang Well in Anhui, China

Abstract

The Lujiang well, a 63 °C artesian well, recorded sustained hydrological changes following the 1999 Chi–Chi M w 7.6, the 2008 Wenchuan M w 7.9, and the 2011 Tohoku M w 9.0 earthquakes, including rises in the water radon concentration, water pressure, discharge and water level, and drops in the water temperature. These hydrological changes are synchronous and have similar amplitudes. The permeability inferred through the tidal response of water level showed insignificant change after the three earthquakes. We attribute the observed hydrological changes to the increase in the vertical recharge on the basis that the water radon concentration of the Lujiang well increased following the increase of recharge to the well; significant vertical flow exists in the well-aquifer system; the well has a lower water radon concentration and a higher water temperature than its adjacent wells with different aquifers.