Azimuthal variation in shear wave speed and existence of two shear wave arrivals are commonly assumed to be diagnostic of fractured rock. These properties derive from a representation of fractured rock as an effective anisotropic medium. Work on effects of single fractures suggests that energy can be partitioned in ways that are not captured by the effective medium representation. Single fractures cause frequency dependent reflections, refractions and group time delays in plane waves and can trap energy as interface waves. These effects can result in distinctive seismic signatures in multiply fractured rock.