What happens where two plates meet?

• A. Plates never interact
• B. The interaction can cause earthquakes, volcanic activity, or mountain ranges, depending on the boundary type
• C. Only earthquakes
• D. Only mountain formation

Answer: (B)

When two plates meet, what happens depends on how they move at that boundary. At divergent boundaries, plates pull apart and magma rises to fill the gap, creating new crust and often volcanic activity, with earthquakes along the rift. At convergent boundaries, plates collide—one may dive beneath the other—producing deep and powerful earthquakes and volcanic arcs, or, when continents collide, building tall mountain ranges. At transform boundaries, plates slide past one another, causing frequent earthquakes but little volcanism. So the outcome can be earthquakes, volcanic activity, or mountain building, depending on the boundary type.