Fracture rocks at depth are generally harder to break due to the increased confining pressure from the overlying rock layers. This confining pressure restricts the opening of existing fractures and requires a higher applied stress to cause further fracturing. Additionally, the presence of elevated temperatures at depth can cause the rocks to become more ductile, reducing their susceptibility to fracturing.«Characterisation and evolution of the full size range of pores and fractures in rocks under freeze-thaw conditions using nuclear magnetic resonance and three-dimensional x-ray microscopy »