3:15 PM - 3:30 PM
★ [SCG60-12] Coseismic fluid-rock interactions in subduction-zone faults: Constraints from geochemical analyses of fault rocks
Keywords:fluid-rock interactions, fault rocks, earthquake, geochemistry, subduction zones
Geochemical evaluation of coseismic fluid-rock interactions in fault zones is useful means not only to understand the slip mechanism (e.g. thermal pressurization) but also to constrain compositions of the fluids in the fault zones. Trace element and isotope characteristics of slip-zone rocks from the Midian Tectonic Line in Japan (Ishikawa et al., 2014) and from the Kodiak accretionary complex (Yamaguchi et al., 2014) both requires interactions with high-Li fluids, which implies that coseismic hydrothermal processes took place in the presence of fluids that had migrated from the depth.