Exploring slow slip events and their scaling in 3D simulations of fault slip

Luca Dal Zilio, Nadia Lapusta, & Jean-Philippe Avouac

Published August 14, 2019, SCEC Contribution #9622, 2019 SCEC Annual Meeting Poster #175

Tectonic faults accommodate a wide spectrum of slip modes, ranging from earthquakes to slow slip events (SSEs). While regular earthquakes are events with rupture velocities governed by inertial stress transfer with elastic wave speeds, the physical mechanisms which govern slow fault slip phenomena are less understood. In particular, key questions remain about how SSEs nucleate and propagate and whether they follow scaling laws different or not from ordinary earthquakes. Here we investigate this issue by simulating sequences of SSEs, in the case of a three dimensional model of a subduction megathrust governed by rate and state friction with or without dilatant strengthening. By testing a wide spectrum of frictional properties, we investigate under which conditions sliding instability develops into sustained slow slip events. In particular, we study the processes that control variations in slip velocity, propagation speed, stress drop, as well as the aspect ratio of individual uni- and bi-directional SSEs. Finally, we compare the scaling laws relating the released moment to the duration and rupture area of the SSEs for comparison with scaling laws derived from kinematic inversions of GPS time series.

Key Words
Slow Slip Events; Modeling; Megathrust; Scaling

Citation
Dal Zilio, L., Lapusta, N., & Avouac, J. (2019, 08). Exploring slow slip events and their scaling in 3D simulations of fault slip. Poster Presentation at 2019 SCEC Annual Meeting.

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