Fluid Flux Passing through Fault Zones – One Step to Understand Whole Fluid Budget in the Subduction Zone

Abstract:

For fluid circulation in and around subduction zone, fluid of deep origin flown out at the surface is important source to infer the total fluid budget. We present here the results of chemical and physical modeling for fluid flux of the fault zone through hot springs at Arima area, SW Japan. After hot spring drillings at the 1940 to 1950's constant amounts and quality of these hot springs have been maintained by local government office of Kobe City.

Many researches have been done for the hot springs so far, including surface geology, shallow underground structure, source of fluids and fluids paths. Fluid paths are so clear to be fracture zones of particular fault zones by results of geological survey and resistivity analysis. It is also well known that fluids from Arima hot springs show specific isotopic compositions, which is inferred to be deep origin. In this presentation, we discuss about quantification of fluid flux from deep crust using long-term monitored chemical data from Arima hot spring. This is a first step to monitor the fluid dynamics along the fault zone associated with crustal activities. Further collaboration with geophysical observations is worthy in future.