Question

multiple select question
select all that apply
at which plate boundaries do earthquakes tend to be shallow, typically less than 70 km depth?
□ divergent plate boundaries
□ convergent plate boundaries
□ transform plate boundaries

Explanation:

• Divergent plate boundaries: At divergent boundaries, tectonic plates move apart. The stress and movement here lead to relatively shallow earthquakes as the plates are just separating at the surface - level (upper crust) in most cases. For example, along the Mid - Atlantic Ridge, the separation of plates causes earthquakes that are shallow.
• Transform plate boundaries: At transform boundaries, plates slide past each other horizontally. The movement is mainly along a fault plane in the upper crust. Since the interaction is at the surface - level (compared to the deep - seated processes at some convergent boundaries), the earthquakes are shallow. The San Andreas Fault is a classic example where shallow earthquakes occur due to the lateral sliding of plates.
• Convergent plate boundaries: At convergent boundaries, one plate is subducted under another. While there can be shallow earthquakes near the trench (where the plates first interact at the surface), there are also deep - seated earthquakes as the subducting plate goes deeper into the mantle. So, convergent boundaries are not characterized by only shallow (less than 70 km depth) earthquakes.

Answer:

• divergent plate boundaries
• transform plate boundaries