FINITE STRAIN ANIMATIONS OF CONTINENTAL DEFORMATION FOR RESEARCH AND EDUCATION

Animations of finite strain within deforming continental zones can be an important tool for both research and education. I present finite strain models for western North America. These models use instantaneous rates of strain inferred from both space geodetic observations and Quaternary fault slip rates. Geodetic velocities and Quaternary strain rates are interpolated to define a continuous, instantaneous velocity field for western North America. This velocity field is then used to track topography points and fault locations through time, using small time steps. The strain rate solution is determined at each time step, accounting for changes in boundary conditions of plate motion, and changes in fault orientation. Assuming zero volume change, erosion rates, and Airy isostasy, the topography is also calculated as a function of time. The animations provide interesting moving images of continental evolution through. These animations are an excellent demonstration for education purposes and also hold potential as an important tool for research. The models point to numerous shortcomings of taking constraints from instantaneous calculations to provide insight into time evolution and reconstruction models. More rigorous calculations are needed to account for changes in dynamics (body forces) through time and resultant changes in fault behavior.