when a downgoing plate (usually composed of oceanic lithosphere) submerges beneath an overriding plate shallow earthquakes occur at the plate boundary and deeper earthquakes occur in the downgoing plate as it sinks into the earth. the deep earthquakes caused by the downgoing plate form the wadati–benioff zone. the deepest recorded earthquakes come from wadati–benioff zones and can extend to depths as much as 650 km (400 mi) deep.