Slow-slip evolves into megathrust earthquakes in 2D numerical simulations
Article first published online: 28 SEP 2012
©2012. American Geophysical Union. All Rights Reserved.
Geophysical Research Letters
Volume 39, Issue 18, September 2012
How to Cite
2012), Slow-slip evolves into megathrust earthquakes in 2D numerical simulations, Geophys. Res. Lett., 39, L18308, doi:10.1029/2012GL052811., and (
- Issue published online: 28 SEP 2012
- Article first published online: 28 SEP 2012
- Manuscript Accepted: 14 AUG 2012
- Manuscript Revised: 10 AUG 2012
- Manuscript Received: 21 JUN 2012
- earthquake triggering;
- fault dynamics;
- slow slip
 Slow slip events (SSE) in many subduction zones incrementally stress the adjacent locked megathrust, suggesting that they could potentially either trigger or evolve into damaging earthquakes. We explore this with 2D quasi-dynamic simulations with rate-state friction, dilatancy, and coupled 1D pore-fluid and heat transport. Steady-state weakening friction allows transient slip to nucleate, but is inhibited by dilatant strengthening and destabilized by thermal pressurization. SSE spontaneously nucleate in Low Effective-Stress Velocity-Weakening (LESVW) regions. If the dimension of the LESVW is relatively small the SSE are trapped at its updip end, imparting a strong stress concentration in the locked zone. After several centuries SSE penetrate into the region of higher effective stress, where thermal pressurization eventually leads to dynamic rupture. For larger LESVW regions SSE tend to increase in length with time; ultimately higher slip speeds enhance thermal weakening, leading to dynamic instability within the SSE zone. In both cases the onset of the ultimate SSE is essentially indistinguishable from preceding events.