Changes in groundwater level and temperature induced by distant earthquakes

Abstract

We analyzed the co-seismic responses of groundwater level and temperature in the Tayuan Well, Beijing, China, induced by 85 distant earthquakes over the period from January 2004 to July 2009. The results show that the Tayuan Well records earthquakes worldwide and that the co-seismic response shows the following pattern: water-level oscillation, temperature decrease, oscillations stop, return to normal temperature. The amplitudes of changes in water level and temperature are related to the earthquake magnitude and the distance to the epicenter. We discuss the mechanisms of the decrease in water temperature during the period of oscillations in water level, and the mechanisms of the temperature increase subsequent to the cessation of oscillations. We also analyze the results of previous studies on co-seismic response mechanisms, and consider the mechanisms of gas escape, heat diffusion, and cold-water seepage. These mechanisms may have induced the decrease in water temperature recorded in the present study, and the subsequent return to normal temperatures was due to heat exchange between the well water and the surrounding wall rock.