Landslide subsurface slip geometry inferred from 3‐D surface displacement fields

Abstract

Abstract The stability of many large landslides is determined in part by deformation along buried, often inaccessible, slip surfaces. Factors such as infiltrating rainfall on the slip surface lead to stability changes. Yet characterizing the depth and shape of this slip surface is challenging. Here we examine the hypothesis that the subsurface slip geometry can be constrained by ground surface displacements in concert with two, mechanically distinct, forward models. We estimate a 3‐D ground displacement field for the slow‐moving Cleveland Corral landslide in California using repeat terrestrial laser scanner data. We test the efficacy of two models to estimate slip depth and slip magnitude of the slide—a 2‐D balanced cross‐section method and an elastic dislocation model. The estimated slip surface depth using both methods matches in situ observations from shear rods installed in the slide within the ±0.45 m misfit indicating that these are valuable approaches for investigating landslide geometry and slip behavior.