APPLICATION OF GEOMETRIC MODELS TO INVERTED LISTRIC FAULT SYSTEMS IN SANDBOX EXPERIMENTS. PAPER 1: 2D HANGING WALL DEFORMATION AND SECTION RESTORATION

Abstract

Fault geometry is a primary control on hanging wall deformation. In order to examine their geometrical relationships, a positive inversion analogue experiment was conducted using a rigid fault surface of listric geometry. The hanging wall deformation observed on a representative vertical section was examined with conventional 2D geometric models, and was restored to its pre-inversion phase with two techniques. These results suggest that the deformation can be best approximated by inclined simple shearing (ISS). The ISS model can determine the inclination of the apparent shear plane and the amount of apparent horizontal shortening, which is equivalent to that calculated with the conventional depth-to-detachment method. This estimated apparent shortening was generally smaller than the actual amount of the experiments, probably due to tectonic compaction.