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...

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Veröffentlicht in:Geophysical research letters 2020-12, Vol.47 (23), p.n/a
Hauptverfasser: Heimisson, Elías R., Avouac, Jean‐Philippe
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Sprache:eng
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Zusammenfassung: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 ta. 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. Plain Language Summary The surface of Earth and many other planets and moons is constantly being stressed in an oscillatory manner, for example, by the gravitational pull of moons, planets, and suns. Further, weather, climate, oceans, and other factors may also generate oscillatory stresses. The resulting fluctuations in stress may result in an increased or decreased probability of earthquakes with time. Here we derive a simple formula that can help scientists understand how these oscillatory stresses relate to seismic activity. Moreover, we revisit a recent estimate of the maximum sensitivity of marsquakes to tides and reach a different conclusion. Key Points We derive a simple analytical model for seismicity rate based on rate‐and‐state friction The model can be applied to perpetually oscillating stresses on Earth and other solid‐surface bodies We reevaluate recent work on possible tidally triggered seismicity on Mars
ISSN:0094-8276
1944-8007
DOI:10.1029/2020GL090827