Oscillations in fluid pressure caused by silica precipitation in a fracture

Ubiquitous quartz veins within the crust underscore the contribution of silica precipitation to fault sealing and fluid-pressure changes during earthquake cycles. However, quantifying silica precipitation, fluid pressure fluctuations, and earthquake rupture remains challenging. Here, we present the results of hydrothermal flow-through experiments with constant flow rates that show silica precipitation reduces permeability and induces fluid-pressure oscillations in the flow of highly supersaturated fluid. Following an induction period, the difference between inlet and outlet pressures in the experiments increased and oscillated, reaching a peak before abruptly decreasing, while the background pressure difference increased gradually. Such pressure oscillations resulted from the repeated blockage of flow pathways by silica and the failure of locally sealed layers, which produced characteristic quartz textures. The results suggest that the generation and transport of silica particles in fluid, driven by failure events, may induce transient and local variations in fluid pressure, thereby contributing to earthquake rupture.