Conrad Discontinuity
Conrad Discontinuity : Seismic boundary between the upper and middle crust that is usually defined by an increase in seismic velocity from 6.2-6.4 km/sec to about 6.6-6.8 km/sec. The term has fallen into disuse in recent years due to the lack of universality of such a discontinuity. See: Mooney et al. (2002), and the biography of Victor Conrad in Howell (2003)