Volcanic eruptions that occur over subduction zones at convergent plate boundaries are (20points)

small-scale and nonviolent

made mostly of relatively cool slow-moving lava

infrequent but highly explosive

frequent but with slow-moving lava

Infrequent but highly explosive  

Explanation:

At a subduction zone, the descending plate carries with it sediments containing water and carbon dioxide.

These substances are trapped as fluids at high pressure in the rising magma.

When they reach atmospheric pressure at the surface, they become gases that expand suddenly and explosively.