Meaning of Benioff zone

Ben'i•off zone"

Pronunciation: (ben'ē-ôf", -of"), [key]
— Geol., Oceanog. Geol.,Oceanog.
  1. a planar seismic zone in oceanic crust along which subduction of lithospheric plates gives rise to frequent earthquakes: marked by oceanic trenches sloping downward at about 45° toward adjacent island arcs or continents.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.