Abstract Fault zones are inherently heterogeneous and exert significant impacts on fluid injection‐induced activities. We conducted Low‐velocity shear experiments on homogeneous (HM) and layered (LM) clay‐quartz mixtures representing gouge heterogeneity under double direct‐shear and constant fluid injection. Cyclic fault‐valve is activated in LM faults when the clay content is ≥50%, while it is absent in HM faults. A segmental layer of low‐permeability clay perpendicular to the flow direction acts as a fault‐valve, causing cyclic build‐up then dissipation in pore pressure, hence influencing the magnitude of shear stress drop and sliding distance associated with seismic magnitudes. Recovered seismic moments from individual fault‐valve cycles are bounded by the maximum seismic moment M0max=c2(1−c)G∆V′ ${M}{0}^{\max }=\frac{c}{2(1-c)}G\mathit{{\increment}}{V}^{\mathit{\prime }}$ when a pre‐stress coefficient c ranges 90–99%. This study highlights the role of spatial distributions in pore pressure as controlled by gouge compositions and spatial heterogeneity on slip stability, and verifies the applicability of M0max−∆V′ ${M}{0}^{\max }-\mathit{{\increment}}{V}^{\mathit{\prime }}$ relation to fault‐valve systems.

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