noun Geology, Oceanography.
- 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.
noun
- a long narrow region, usually adjacent to a continent, along which earthquake foci lie on a plane which dips downwards at about 45° and along which the oceanic lithosphere is thought to be descending into the earth’s interiorCompare subduction zone