Generation of oxidising fluids by comminution of fault rocks

Mechanochemical reactions exert a crucial control on the chemical environments of crustal fault zones during co-seismic and post-seismic periods. Comminution due to faulting causes activation of fault rock surfaces, such as the production of reactive radical species. In this study, we report on the generation of H2O2 by immersion of comminuted sedimentary, igneous, and metamorphic rocks that are broadly representative of those present at a variety of depths in subduction zones. Our experiments demonstrate that fresh surfaces of these rocks have an H2O2 productivity of 1.3-10.4 nmol m(-2) (mean = 5.4 nmol m(-2)). Ina natural fault zone environment, H2O2 produced after a slip event is likely to react with Fe-bearing mineral surfaces or Fe2+ in porewater, or thermally decompose to produce more oxidative center dot OH. The oxidising fluid produced by fault rupture in one patch may spread and induce corrosion and degradation of surrounding fault zones. These chemical processes are likely to be important factors influencing the interaction between neighbouring seismic activities.

Automated summary

Mechanochemical reactions in crustal fault zones play a crucial role in controlling the chemical environment during seismic events. The production of H2O2 after a slip event may react with Fe-bearing minerals or Fe2+, leading to further oxidative reactions. These chemical processes could influence the interaction between neighboring seismic activities.