Benioff zones are dipping, roughly planar zones of increased earthquake activity produced by the interaction of a downgoing oceanic crustal plate with an overriding continental or oceanic plate. They occur at boundaries of crustal plates called subduction zones. The earthquakes can be produced by slip along the subduction thrust fault or by slip on faults within the downgoing plate, as a result of bending and extension as the plate is pulled into the mantle. The zones have dips typically ranging from 40 to 60 degrees. The zones are also known as the Wadati-Benioff zone.

During the past century, improvements in seismic acquisition and processing led to the observation that the world's earthquakes are not randomly distributed over the earth's surface. Rather, they tend to be concentrated in narrow zones along the boundaries of continental and oceanic crustal plates. According to the plate tectonic theory, the crust of the...