A model of fault propagation in rocks under compression

In the literature, faults are often treated as shear cracks. However, laboratory and field observations, as well as theoretical reasoning suggest that shear cracks do not grow in their own planes. The proposed model assumes that the fault propagates by successive connections of wing cracks sufficiently grown due to the stress concentration at the fault front. This mechanism makes the fault “thick” and, hence, restricts the stress concentration. It is shown that while this stress concentration is sufficient for connecting wing cracks, it is not enough to produce tensile out-of-plane growth. The criterion of fault propagation has been derived for a particular case of low lateral pressure. The authors’ names are listed alphabetically.