Kinematics and visualization of strain in three dimensions
Koomen, Amy Corinne
Gordon, Richard G.
Master of Arts thesis
A new computer program for strain visualization has been written. Given an upper triangular deformation tensor, which corresponds to homogeneous deformations where no shearing occurs in the z-direction (assuming a right-handed reference system), the program calculates and displays the strain ellipsoid. In addition, it can show the orientations and magnitudes of the finite strain axes, paths of particle motion, instantaneous strain axes, vorticity vector, and flow apophyses. The strain visualization program has been applied to the wrench-dominated transconvergence of the Pacific-Sierra Nevada plate boundary. I find that, within the uncertainties, the two end-members of accommodation of fault-normal contraction can produce finite strain axes matching the orientation of the mean fold-axis azimuth of the California Coast Range. Furthermore, I find that modeling the regional geology as though it were experiencing coaxial deformation is not an invalid oversimplification.