Supersonic impact, shock and frictional processes in planetary materials

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This proposal seeks funding to investigate high strain-rate phenomena in planetary materials. Many geological processes take hundreds, thousands or millions of years to complete. In contrast, dynamic events associated with asteroid impact typically occur in less than a second (shock wave passage), with a total event lasting minutes (dominated by gravity-driven readjustments). Coseismic slip is typically several seconds duration for a large earthquake. Our collective knowledge of "fast" deformation is limited, especially in terms of the response of natural ceramics (i.e., most planetary materials). I will investigate two main areas of dynamic behaviour: (1) hypervelocity impact, and associated shock wave-materials interactions, and (2) seismogenic faulting via laboratory-based simulations and field studies. The impact research will embrace shock wave generation and the transformation of materials in the solid state (e.g., the creation of new high-pressure and high-temperature mineral states), as well as their conversion into melt and vapour. Associated graduate student training at the Master's and PhD levels will focus on terrestrial impact craters (e.g., Manicouagan), lunar, martian and asteroid materials, and shock and frictional processes. Emphasis will be placed on understanding shock and associated shock focussing mechanisms, the latter resulting in shock energies greater than the bulk shock. Seismogenic faulting research will relate the mechanics of the sliding interface to seismic hazard in terms of fault lubrication and earthquake magnitude. Along with a state-of-the-art laboratory-based friction apparatus used to simulate earthquakes, my recently established high-speed impact laboratory provides the research foundation for directly investigating shock wave-materials interactions. The proposed activities will further our understanding of materials behaviour under extreme conditions. This is relevant to (a) understanding impact and shock as fundamental planet-building and planet-modifying processes, and (b) developing protective materials for our society (e.g., impact shielding for space-based infrastructure). An enhanced knowledge of earthquake mechanics will help characterize hazardous fault systems, with the goal of developing new predictive tools.