Fig. 9
Adapted from Kupferschmied et al. (2015), 108, Copyright 2015 Elsevier Ltd., with permission from Elsevier
Sketches obtained from the macroscopic analysis of the typical BDZ-structures around a circular opening drilled parallel to the bedding plane orientation (S0): a dominating tangential fractures developed in only one direction (more often observed), b tangential fractures extending in opposing directions (occasionally observed).