Abstract
The Dupuit-Ghyben-Herzberg model was applied to the Awajishima Island to explain hydrologic changes associated with the 1995 Hyogo-ken Nanbu (Kobe) Earthquake, and hydraulic properties (hydraulic conductivity, specific yield) were estimated using the available quantitative data. Results indicate that the hydraulic conductivity has increase at least 5 times over the pre-seismic value, and that the specific yield of the unconfined aquifer is at around 0.3 to 1.7% depending on the assumed recharge rate but regardless of the depth to the impermeable basement. Upward migration of deeper water due to salt-water intrusion may explain the change of chemical composition of discharged water. This analysis suggests the necessity of measuring the increase of the discharged water just after an earthquake to properly estimate the change in the hydraulic conductivity of the aquifer.
