Question

mount st. helens and the cascade mountain range were formed where the juan de fuca (ocean) plate dives beneath the north american (continental) plate. what is it called when one plate buckles downward into the earths mantle? (1 point)
intertidal
pelagic
rift
subduction

Explanation:

Subduction is the process where one tectonic plate (oceanic in this case) moves beneath another (continental) into the Earth's mantle. Intertidal refers to the zone between high and low tide. Pelagic relates to the open sea. A rift is a linear zone where the Earth's crust is being pulled apart. So, the correct term for one plate buckling downward into the mantle is subduction.

Answer:

subduction