Prevalent seismic nucleation phases indicating a common cascading earthquake rupture growth trajectory
Haoran Meng, & Wenyuan FanSubmitted March 1, 2021, SCEC Contribution #10957
Understanding the seismic nucleation phase is essential for deciphering earthquake rupture physics and can aid earthquake probabilistic forecasting. However, the impacts of the seismic nucleation phase on the later stage rupture are rarely systematically examined for a large set of events in a single fault system. With regional dense seismic arrays, we identify seismic nucleation phases of 527 0.9≤M≤ 5.4 events of the 2019 Ridgecrest earthquake sequence, including 48 earthquakes with series of precursors. The observations indicate a complex rupture development trajectory. These nucleation phases generate seismic precursory signals that are almost identical to the earthquake P-waves, but the precursor attributes show no clear scaling relationships with the earthquake magnitude. Our observations suggest that earthquake rupture may initiate in a universal fashion but evolves stochastically. This indicates that earthquake rupture is likely controlled by fine-scale fault heterogeneities, and the final magnitude is the only difference between small and large earthquakes.
Citation
Meng, H., & Fan, W. (2021). Prevalent seismic nucleation phases indicating a common cascading earthquake rupture growth trajectory. Geophysical Research Letters, (submitted).
