Computer Modeling of Large Rock Slides

A computer-based analysis of the runout dynamics of the Madison Canyon rockslide of August 17, 1959, is reported. Three levels of computer representation of the flow are considered. First is a representation of the actual canyon profile, where the model assumes incompressible linear viscous flow. Second is a horizontal profile in which gravitational forces are input by components, and again the flow is approximated by a single viscosity model. Third is a horizontal profile, for which a two viscosity model approaching a Bingham material representation is used. Results of each model are compared to actual slide runout, debris distribution, and maximum speed of the flow. The biviscous model, which depicts an active basal flow layer, also has physical characteristics consistent with measurements made of the Madison Canyon slide following the event.