We argue that fracture surfaces may exhibit anomalous dynamic scaling
properties akin to what occurs in some models of kinetic roughening. We
determine the complete scaling behavior of the local fluctuations of a brittle
fracture in a granite block from experimental data. We obtain a global
roughness exponent χ=1.2 which differs from the local one, χloc=0.79. Implications on fracture physics are discussed.Comment: 4 pages, LateX, 4 figures, uses epsf. Accepted for publication in PR