Classification of fracture patterns by heterogeneity and topology Andreas Hafver, Espen Jettestuen, Maya Kobchenko, Dag K. Dysthe, Paul Meakin and Anders Malthe‐Sørenssen EPL, 105 5 (2014) 56004 Published online: 14 March 2014 DOI: 10.1209/0295-5075/105/56004