Mineral reactions related to fluid flow operating before, during and after the seismic cycle have long been recognized in active and exhumed fault zones. Field studies indicate that earthquakes in subduction- and orogenic root zones may be spatially related to domains where mineral reactions take place at non-equilibrium conditions. Subduction zones, for example, are characterized by instabilities caused by increasing PT conditions that drive metamorphism and dehydration as the deeper parts are approached. Incremental lithification, phase transformations, and fluid-rock interactions can lead to the onset of localization of deformation and ultimately seismicity. At shallow depths seismicity has been related to either a lithification threshold within fault assemblages or diagenetic and low-grade metamorphic reactions. Two hypotheses have been proposed to explain the seismicity at depth; (1) that fluid-pressure-embrittlement triggers earthquakes, and (2) that melt-shear-instabilities trigger seismic slip. The quantitative relationships between metamorphism, fluid flow, and seismicity remain, however, not fully understood. We invite contributions that address these feedback relationships at all depths. We are looking for an interdisciplinary discussion with contributions based on field work, rock-deformation experiments, seismology and modeling.