The Wadati-Benioff Zone is a dipping area of earthquake foci that tracks the path of a subducting tectonic plate as it sinks into the mantle. It can extend to depths of up to 700 km. It provides visual evidence that one plate is being forced beneath another into the Earth’s interior. ANSWER: (C) Wadati-Benioff Zone
In a subduction zone, the planar zone of seismicity produced by the down-going oceanic plate is called the: (A) Mohorovičić Zone (B) Gutenberg Zone (C) Wadati-Benioff Zone (D) Richter Zone
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This zone is characterized by shallow-focus earthquakes near the trench, intermediate-focus quakes further inland and deep-focus quakes at the furthest extent. As the brittle oceanic slab descends into the hotter, more plastic mantle, it remains cool enough to fracture and generate earthquakes for a few hundred kilometers. Beyond 700 km, the rock becomes too hot and ductile to break, ending the seismic zone. Mapping these zones allowed geologists to confirm the theory of Plate Tectonics and understand the geometry of subduction angles around the Pacific Ring of Fire.