1. n. [Geophysics]
A type of event produced by the radial scattering of a wave into new wavefronts after the wave meets a discontinuity such as a fault surface, an unconformity or an abrupt change in rock type. Diffractions appear as hyperbolic or umbrella-shaped events on a seismic profile. Proper migration of seismic data makes use of diffracted energy to properly position reflections.
See: abnormal events, acquisition, arrival, hydrocarbon indicator, Kirchhoff migration, raypath, reflection, time migration, wavefront