Analytical Prediction of Seismicity Rate Due to Tides and Other Oscillating Stresses

Oscillatory stresses are ubiquitous on Earth and other solid-surface bodies. Tides and seasonal signals perpetually stress faults in the crust. Relating seismicity to these stresses offers fundamental insight into earthquake triggering. We present a simple model that describes seismicity rate due to perpetual oscillatory stresses. The model applies to large-amplitude, nonharmonic, and quasiperiodic stressing. However, it is not valid for periods similar to the characteristic time t_a. We show that seismicity rate from short-period stressing scales with the stress amplitude, but for long periods with the stressing rate. Further, that background seismicity rate r is equal to the average seismicity rate during short-period stressing. We suggest that Aσ₀ may be underestimated if stresses are approximated by a single harmonic function. We revisit Manga et al. (2019, https://doi.org/10.1029/2019GL082892), which analyzed the tidal triggering of marsquakes and provide a rescaling of their seismicity rate response that offers a self-consistent comparison of different hydraulic conditions.