Period-Multiplying Cycles & Implications for the Parkfield Period-Doubling Tremors

Event Type: Seminar

Date: 30 April 2021, 16:00 to 17:00

About the Event

The recurrence patterns of the Parkfield tremors with period-multiplying slow and fast ruptures provide new insights on the physics of earthquake cycles. However, the mechanisms behind the peculiar recurrence pattern and the coupling between slow-slip events and seismic radiations are still unclear. Here, we conduct direct-shear experiments on polycarbonate and granite fractures under varying stress conditions to investigate the variations of rupture properties near the stability transition. Laboratory slow and fast ruptures sequences produce slip-predictable period-multiplying cycles with correlative acoustic energy release, stress drop, event duration, and recurrence intervals. However, gouge accumulation by damage of the granite fracture provokes changes in stiffness and stress drops ratios over multiple cycles, affecting the recurrence intervals and energy release of consecutive slip events. These findings confirm the link between low-frequency earthquakes and underlying slow-slip events, with period-multiplying cycles naturally occurring near the stability transition.

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About the Speaker

Mei Cheng

Mei Cheng is a final-year Ph.D. student at School of Civil and Environmental Engineering, Nanyang Technological University. Mei's research covers earthquake mechanics, seismic cycles, acoustic emission, seismic data processing, machine learning, rock mechanics, etc. Mei recently published the laboratory finding on the recurrence pattern of Parkfield tremors and the coupling between slow-slip events and seismic radiations (Mei et al., Geophys. Res. Lett., 2021, https://doi.org/10.1029/2020GL091807). Mei is also experienced in machine learning and interested in earthquake prediction.