Process of rock fracturing caused by geofluid: Focus on geological evidence

Abstract

Geofluid is considered to provide important effect on earthquake generation related to the subducting slab. We found recently cataclastic rocks in Hiraodai-Karst, which was probably formed by hydrofracturing. In this study, we tried to clarify the formation mechanism of the cataclastic rocks and origin of the fluid. We succeeded in identifying the area of distribution of the cataclastic rocks, which suggests that it was not created by fault activity. And the present data reveals that (1) fluid-induced differential stress produceed cataclasite zone in the marble body, (2) this cataclasite-producing fluid was possibly cogenetic to the magma of adjacent the granodiorite.