Inferring fault characteristics using fold geometry constrained by Airborne Laser Swath Mapping at Raplee Ridge, Utah

Abstract

We used Airborne Laser Swath Mapping (ALSM) data to define the geometry of strata in Raplee Ridge in southeastern Utah that were likely deformed by slip on an underlying fault. The fold geometry was used to infer the fault geometry and loading responsible for the folding using the Boundary Element Model, Poly3D. Monte Carlo Markov-Chain (MCMC) methods created probability density functions (pdfs) that reveal the most likely fault geometry and loading conditions and their uncertainties. Despite the restrictive assumptions of Poly3D, in which body deformations occur from slip on displacement discontinuities in a homogeneous linear-elastic half-space, the strata deflections are matched remarkably well, and the resulting inferences of fault geometry and stress field appear reasonable. We propose that similar methods may be used with models that include more complicated rheologies and heterogeneous and anisotropic material properties to estimate fault geometries and loading conditions where only deflection of strata record these parameters. Copyright 2007 by the American Geophysical Union.