Potential for landsliding: Dependence on hyetograph characteristics

This paper examines the effect of hyetograph shape on the potential for landsliding in soil-mantled landscapes. An existing pore pressure response model (Iverson, 2000) is used to study the effects of unsteady rainfall infiltration in hillslopes, and the effect of slope and convergent topography is expressed using a steady state model of slope-parallel subsurface flow. Slope stability is assessed using an infinite slope analysis. This theoretical framework is coupled with simple hyetograph models and to intensity-duration-frequency functions to determine the return period of landslide-triggering rainfall. Results also show that hyetographs with a peak at the end of a rainfall event have a stronger destabilizing effect than hyetographs with a constant rainfall or with a peak at the beginning of a storm. Thus the variability of hyetograph shapes adds uncertainty to the assessment of landsliding triggered by rainfall.