Fluid inclusion evidence of post-seismic fluid flow induced by dynamic rupture

Abstract

Earthquake induced fault damage can create considerable fracturepermeability in and around fault zones initiating large fluxes of fluid, particularly at fault terminationsand dilatational jogs. In this work we show that fluids from both shallow and deep origins can also bechanneled and potentially mixed through a network of interconnected high angle microfracturesgenerated by transient stress perturbations associated with a passing earthquake rupture. By using theorientation, chemical composition and salinity in ca. 200 fluid inclusions trapped in healedmicrofractures in the damage zone of the Caleta Coloso Fault (Northern Chile), we constrain thesource and relative timing of fluid flow associated with earthquake induced microfractures in thedamage zone of a large crustal scale strike slip fault.