If you want to make your own visualizations of this type, you can download the software and the data free! From the UC Davis Keck Center for Active Visualization in the Earth Sciences. EPIC POWER to VISUALIZE.

Wadati's discovery of dipping tabular earthquake zones beneath Japan! The countour map of eq depth showing the top of the subducting slab
Also check out Cliff Frohlich's 1987 tribute to Wadati's career contributions

Benioff linked the dipping earthquake zones to plate boundaries: 1949 diagrams of the contact zone between ocean and continent
That figure comes from this paper, which also links these deep ocean trenches to tsunamigenesis