Christine McCarthy, Lamont Doherty Earth Observatory of Columbia University

Antarctic ice streams that exhibit stick-slip events sufficient to generate seismic waves are demonstrating velocity weakening behavior as defined by rate- and state- dependent friction. Healing between events is a necessary condition of stick-slip. We have conducted laboratory experiments to better constrain healing and frictional stability in a simplified ice-on rock system, quantifying the relevant parameters via velocity steps and slide-hold-slides. In particular, we measure healing rates that are orders of magnitude greater than typically measured in rock friction experiments. Additionally, oscillatory velocities were used to explore the role of tidal modulation on friction and healing and rate-state values obtained can be used to forward model to dynamic systems.  

Short biography
Christine McCarthy is an Associate Research Professor at Columbia’s Lamont-Doherty Earth Observatory. She received her Masters and Ph.D. from Brown University, after which she conducted a two-year postdoc in Tokyo at the Earthquake Research Institute. She specializes in designing and conducting laboratory experiments that measure how ice and other geologic materials respond to external forcing at various timescales, such as how glaciers slide or how seismic waves are damped as they travel through the Earth. In particular she is interested in how features at the microscopic scale affect macroscopic-scale behavior. Recent projects have expanded her research into carbon mineralization and technology testing for outer solar system mission design.