Discontinuous Crack Fronts of Three-Dimensional Fractures
  The relation between fracture surface morphology and the three-dimensional structure of crack fronts is investigated through direct observation of brittle cracks in gels. A key notion in this investigation is the discontinuity of the crack front, whose advancement creates the fracture surface. We discuss the significance of our findings in the studies of general three-dimensional brittle fractures. 
Yoshimi Tanaka, Koji Fukao, Yoshihisa Miyamoto, and Ken Sekimoto