WadatiBenioff

Wadati-Benioff zone is the region of seismic activity in a subduction zone where earthquakes delineate a deep, dipping plane within the subducting oceanic slab. The term honors the seismologists Wadati and Hugo Benioff, who independently documented the pattern of earthquakes associated with subduction. Wadati observed earthquakes occurring at depths beyond the near-surface crust and following a downward-dipping distribution, while Benioff documented deep-focus earthquakes that occur within the subducting slab, solidifying the concept in the mid-20th century.

Earthquakes in the Wadati-Benioff zone extend from shallow interplate events near the trench to deep-focus events that can occur at depths approaching 700 kilometers (about 435 miles) beneath the surface. The seismicity traces a planar feature that reflects the geometry of the subducting plate as it descends into the mantle. This organized pattern provides direct evidence for the subduction process and the three-dimensional structure of subduction zones.

The concept is central to plate tectonics and seismology. It enables researchers to map slab geometry, study rock behavior under high pressure and temperature, and understand earthquake and volcanic activity linked to subduction. The Wadati-Benioff zone remains a fundamental framework for interpreting regional seismicity and assessing hazards in subduction-zone regions worldwide.