Final answer:
Divergent and transform boundaries have only shallow-focus earthquakes, whereas convergent boundaries have a range of depths from shallow to deep due to subduction.
Step-by-step explanation:
Plate boundaries that have only shallow-focus earthquakes are divergent boundaries and transform boundaries.
Convergent boundaries exhibit a range of earthquake depths from shallow to deep due to the subduction process, where the denser, oceanic plate descends into the mantle beneath the overriding plate. On the other hand, divergent boundaries, where plates move away from each other, and transform boundaries, where plates slide past each other laterally, are associated with shallow earthquakes without volcanism, particularly for transform boundaries.
Divergent boundaries have some volcanism due to upwelling of magma, while transform boundaries typically have no volcanism. Therefore, both divergent and transform boundaries are associated with only shallow earthquakes.