An analytical model for fracture nucleation in collapsible stratifications

Abstract

In collapsible stratifications a particular type of fracture can develop for which nucleation and propagation are governed by the transformation of gravitational energy into fracture energy. The associated nucleation problem is studied for a stratification consisting of an elastic surface layer, a collapsible intermediate layer and a rigid basal layer. An analytical model for fracture nucleation is obtained by calculating the energy ('crack energy') associated with a localized collapse of the intermediate layer. The size and energy of a critical crack are evaluated as functions of continuum properties of the strata. The theory is illustrated by an application to the case of whumpfs in collapsible snow stratifications. Copyright 2006 by the American Geophysical Union.