Benioff zone

1. n. [Geology]
A zone of the upper mantle in which earthquakes occur when a lithospheric plate is subducted, named in honor of seismologists Kiyoo Wadati and Hugo Benioff. The dip of this zone, also referred to as the Wadati-Benioff zone, coincides with the dip of the subducting plate. The Wadati-Benioff zone extends to a depth of about 700 km [435 miles] from the Earth's surface.