EEPS Seminar: Ashley Griffith, Ohio State University
Abstract Title: Rock fracture and fragmentation during unstable crustal deformation
Most laboratory research focused on rock strength and failure has been limited to experiments featuring slow, “tectonic” loads; however, many natural processes that pose significant risk for humans (e.g., earthquakes, landslides, and bolide impacts), as well as risks associated with human activities (underground explosions, mine failure, projectile penetration), occur at rates that are hundreds to thousands of times faster than typically simulated in the laboratory. Exhumed rocks deformed during such catastrophic events preserve information about the elusive near-source physics of these processes in unparalleled spatial resolution, yet little experimental data exists to confirm or calibrate theoretical models explaining the connection between damaged rocks and the processes that form them. In this talk I will focus on the study of exhumed fault zones to demonstrate how structural geologists differentiate seismic slip from slow or aseismic slip based on evidence preserved in the rock record and use this information to study the mechanisms of earthquake instability by integrating field observations, laboratory rock mechanics experiments, and theoretical models. I will review some my group’s contributions to this field with particular focus on extreme transient stress conditions associated with propagating earthquake ruptures, including new experimental designs we are using to understand the physics of rock fragmentation in fault zones.