Pulse-like ruptures linked to chaotic recurrence patterns in seismic cycles with compliant fault zones

Shiying Nie, & Sylvain D. Barbot

Published August 15, 2021, SCEC Contribution #11466, 2021 SCEC Annual Meeting Poster #150

Seismic cycles materialize in various rupture styles, from slow-slip events, to slow and fast earthquakes. Meanwhile, the paleoseismic record documents various recurrence patterns for large earthquakes, going from periodic to much more complex sequences. The connection between rupture styles and recurrence patterns is still poorly understood. Here, we explore the quasi-dynamics of two-dimensional faults embedded in a compliant zone for a wide range of frictional and compliant zone properties to document the relationship between rupture style and recurrence patterns. We consider seismic cycles of infinite strike-slip faults surrounded by a low-rigidity damage zone in two-dimensional antiplane strain. We show that a transition from crack-like to pulse-like ruptures can be obtained with increased compliance of the fault zone or reduced characteristic nucleation size of earthquakes. Accompanying the change of rupture style, the recurrence patterns evolve from single-periodic to multiple-periodic cycles, i.e., the repeating cycle of a sequence of slow and fast ruptures, to apparently chaotic cycles of full and partial ruptures. The variability of recurrence times of large earthquakes within the sequence – ignoring aftershocks and slow-slip events – co-evolves with the rupture style. The effects of the compliant fault zone and the other physical properties can be conflated into a single non-dimensional parameter, previously proposed by Kaneko et al. (2011), such that seismic cycles with similar rupture styles and recurrence patterns can be obtained with or without compliant fault zones in quasi-dynamic simulations. The clear connection between rupture style and recurrence patterns implies that detailed paleoseismic records may place important constraints on fault physical properties and rupture characteristics.

Citation
Nie, S., & Barbot, S. D. (2021, 08). Pulse-like ruptures linked to chaotic recurrence patterns in seismic cycles with compliant fault zones. Poster Presentation at 2021 SCEC Annual Meeting.

Related Projects & Working Groups
Fault and Rupture Mechanics (FARM)