Final answer:
The Mariana boundary is a convergent plate boundary within the Ring of Fire, characterized by subduction and volcanic activity. In contrast, the West Coast of North America features a mix of transform and convergent boundaries, including the subduction of the Juan de Fuca plate, leading to volcanic mountain ranges such as the Cascades.
Step-by-step explanation:
The Mariana boundary is a type of plate boundary located in the Ring of Fire, which is known for its high level of earthquake and volcanic activity. This boundary is a convergent plate boundary, where the Pacific Plate is subducting beneath the Mariana Plate, leading to deep-sea trench formation and volcanic activity, contributing to the creation of island arcs like the Mariana Islands.
Along the West coast of North America, from the Gulf of California northward to British Columbia, we encounter different types of plate boundaries. Starting with the San Andreas Fault, a transform boundary, where the Pacific Plate moves northward relative to the North American Plate.
Further north is the Juan de Fuca plate, located off the coast of Washington and Oregon, which is primarily a convergent boundary with the North American Plate. The movement of these plates leads to the subduction of the Juan de Fuca plate, which will eventually be consumed by the Earth's mantle. This subduction process is responsible for the formation of the Cascade Range, including Mount St. Helens, due to tectonic processes that cause volcanic activity.