EFFECT OF MECHANICAL INTERACTIONS ON THE SCALING OF FRACTURE LENGTH AND APERTURE

The aperture (or opening) of a fracture indicates the energy available for fracture growth and controls fracture permeability. The relations hip between aperture and fracture length can therefore be used to infe r the factors affecting fracture formation at different length scales and is of practical importance to hydrogeologists and petroleum engine ers. A recent study(1) of the scaling properties of tensile fractures in the Krafla fissure swarm, Iceland, revealed a distinct break in slo pe in the aperture-length scaling relationship, corresponding to fract ures a few metres in length: this break in slope was interpreted quali tatively as indicative of non-universal, scale-dependent growth mechan isms(1), Here we show, using quantitative fracture simulations, that t he observed non-universal scaling of fracture apertures can be reprodu ced without recourse to multiple growth mechanisms. We argue that the break in slope is instead intrinsic to the fracturing process and repr esents the maximum length scale at which the apertures of smaller frac tures are affected by stress perturbations induced by larger fractures .