A Wadati-Benioff zone is a deep level seismic zone on the line of subduction, which can be as deep as 700 kilometres.

The Wadati-Benioff Zone

The Benioff-Wadati zone.

It is the area of deep earthquake activity that follows the subducting oceanic plate as it grinds its way toward the mantle. The eartquake zones are called Benioff-Wadati zones, after Hugo Benioff, who discovered them in the 1950s

Kiyoo Wadati who discovered the zones of deep seismic activity that mark the downgoing slab of a subduction zone.

These are named Wadati-Benioff zones after Professor Wadati and Professor Hugo Benioff who discovered them at much trhe same time while doing independent research.