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

•Slow slip events on a glacier are analogous to plastic sliding block experiments.•Both systems have low rupture velocities, which increase with applied stress.•Local rupture behavior in both systems can be explained by variations in loading.

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.