Rupture speed dependence on initial stress profiles: Insights from glacier and laboratory

stick-slip

Jacob I. Walter1,4*, Ilya Svetlizky2, Jay Fineberg2, Emily E. Brodsky1, Slawek Tulaczyk1, and

Sasha P. Carter3

1Department of Earth and Planetary Sciences, University of California, Santa Cruz

2Racah Institute of Physics, The Hebrew University of Jerusalem

3Scripps Institution of Oceanography, University of California, San Diego

*Correspondence to: jakeiwalter@gmail.com

4Present address: University of Texas Institute for Geophysics, University of Texas at Austin

Abstract:

Slow slip events are now well-established in fault and glacier systems, though the processes

controlling slow rupture remain poorly understood. The Whillans Ice Plain provides a window into

these processes through bi-daily stick-slip seismic events that displace an ice mass over 100 km long

with a variety of rupture speeds observed at a single location. We compare the glacier events with

laboratory experiments that have analogous loading conditions. Both systems exhibit average rupture

velocities that increase systematically with the pre-rupture stresses, with local rupture velocities

exhibiting large variability that correlates well with local interfacial stresses. The slip events in both

cases are not time-predictable, but clearly slip-predictable. Local pre-stress may control rupture

behavior in a range of frictional failure events, including earthquakes.