Geophysical observations suggest that temporal changes in pore fluid pressure correlate with slow slip events (SSEs) at some subduction zones, including the Hikurangi and Cascadia subduction zones. These fluctuations in pore fluid pressure are attributed to fluid migration before and during SSEs, which may modulate SSE occurrence. To examine the effect of pore fluid pressure changes on SSE generation, we develop numerical models in which periodic pore-pressure perturbations are applied to a stably sliding, rate-strengthening fault. By varying the physical characteristics of the pore-pressure perturbations (amplitude, characteristic length and period), we find models that reproduce shallow Hikurangi SSE properties (duration, magnitude, slip, recurrence) and SSE moments and durations from different subduction zones. The stress drops of modeled SSEs range from similar to 20-120 kPa while the amplitudes of pore-pressure perturbations are several MPa, broadly consistent with those inferred from observations. Our results indicate that large permeability values of similar to 10(-14) to 10(-10) m(2) are needed to reproduce the observed SSE properties. Such high values could be due to transient and localized increases in fault zone permeability in the shear zone where SSEs occur. Our results suggest that SSEs may arise on faults in rate-strengthening frictional conditions subject to pore-pressure perturbations. Plain Language Summary Slow slip events (SSEs), with slower velocities and longer durations than regular earthquakes, have been detected at several subduction zones worldwide. Recent observations have led researchers to infer that pore fluid pressure-the pressure of fluids in the pore space of rocks-changes during SSEs that occur along the shallow (<15 km depth) portion of the Hikurangi subduction zone, where the Pacific Plate subducts beneath the Australian plate. Similar observations have been reported during SSEs in different subduction zones. However, how pore fluid pressure changes are linked to SSEs is poorly understood. To investigate this issue, we develop physics-based models in which periodic perturbations in pore fluid pressure are imposed on a fault governed by the expected frictional behavior of rocks derived from laboratory experiments. These pore fluid pressure perturbations induce SSEs, and the features of these events (duration, magnitude, peak velocity, recurrence interval) change with the characteristics of the pore fluid pressure change (size, amplitude, and period). After exploring different perturbation characteristics, we find models that capture the observed features of SSEs along the Hikurangi margin and in different subduction zones. This study suggests that pore fluid pressure changes may play an important role in SSE occurrence.
