Which type of plate boundary or zone would be most likely to lead to above-ground volcanic activity?

Convergent plate boundary

Explanation:

The convergent plate boundary refers to the type of boundary where two plates move towards each other. Due to this type of motion, there forms a subduction zone, where the denser plate subducts below the lighter plate. This zone of subduction is commonly identified by the presence of a deep and narrow V-shaped depression which is commonly known as the oceanic trench.

When the subducting plate enters into the region of the asthenosphere, the rocks melt and mix with the magma. This magma is then pushed upward due to the force exerted by the convection current that forms in the mantle, and further reaches the over-riding plate and eventually give rise to the formation of volcanoes and volcanic/island arcs.

Thus, this type of plate boundary is responsible for the formation of above-ground volcanic activities.