Elastic interface waves propagating in a fracture

We have made the first direct observation of a new class of elastic interface waves that propagate along the discontinuity of a fracture in a solid. Two propagating eigenmodes were detected in a synthetic fracture in aluminum. The waves are dispersive and polarization dependent, verifying theoretical predictions. The existence of these waves has broad implications, requiring reinterpretation of data from seismic exploration, earthquake detection and nondestructive testing.