Poly-cataclasites: Implications to the Seismic Cycle

Abstract Poly-cataclasites are rocks that have undergone multiple episodic deformational histories. These rocks retained the microstructures developed from older deformational events. They are a common occurrence in the Median Tectonic Line Japan and can be used to evaluate the changes in rock deformational processes throughout the earthquake cycle. Based on the description of mineralogical changes and the microstructures of the cataclasitic clasts, we are able to establish two main deformational events Microstructures of the co-seismic phase relates to the randomly oriented clast developed through fluidisation. Clast that are foliated formed during the aseismic phase through creeping accompanied by the precipitation of phyllosilicate minerals and the consumption of feldspathic minerals. We propose that the presence of crustal fluid circulation is essential in governing the poly-cataclasites deformational cycle providing insights into the underlying deformational processes during the earthquake cycle.