Predictability of Extreme events in a dynamical model of earthquake cycles

Hojjat H. Kaveh, Jean-Philippe Avouac, & Andrew Stuart

Published September 10, 2023, SCEC Contribution #13083, 2023 SCEC Annual Meeting Poster #165

Earthquakes and Slow Slip Events (SSEs) result from episodic slips on faults. Elastic stress transfer between faults or slip patches on the same fault result in a chaotic evolution that challenges the predictability of large events. We quantitatively study the predictability of large slip events in a simplified dynamical model that involves a single planar fault governed by rate and state friction.

The model, featuring a rectangular fault with uniform properties and a constant loading rate, generates realistic sequences of slip events and shows chaotic behavior similar to earthquakes and SSEs in nature. Large slip events propagate through the entire fault and happen irregularly, due to the effects of chaos. The trajectory of the dynamical system has to pass through certain instability regions inside the chaotic attractor for such significant events to happen. Those regions correspond to specific distributions of the state of the frictional interface (characterized by the stress and state variable) that facilitate the propagation of ruptures throughout the entire fault. Outside those instability regions, earthquakes/SSEs can still nucleate but they stop prematurely as partial ruptures.

We find the optimal states in the interevent period that lead to large events while constraining them to be statistically feasible during the seismic cycle using a reduced order representation of the chaotic attractor. The measure of the system's proximity to these optimal solutions is employed to assess the likelihood of large ruptures occurring within a selected time window.

Key Words
Earthquake cycles, system-size ruptures, extreme events, earthquake prediction

Citation
Kaveh, H. H., Avouac, J., & Stuart, A. (2023, 09). Predictability of Extreme events in a dynamical model of earthquake cycles. Poster Presentation at 2023 SCEC Annual Meeting.

Related Projects & Working Groups
Earthquake Forecasting and Predictability (EFP)