Because that is where thee is most magma exerting force
pacific
Usually along convergent plate boundaries, but they can also occur at divergent plate boundaries and hotspots.
Volcanoes occur at divergent and convergent plate boundaries due to the fact that crust is either being destroyed or created. Volcanoes also occur at hotspots, for example in Hawaii. Hotspots occur where the crust is particularly thin or weak, and plumes of magma rising from the asthenosphere (between upper mantle and the crust) end up giving rise to volcanoes or volcanic islands.
At interpolate hot spots
the plates might crash together causing the water above them to jolt, which can cause tsunamis.
Composite volcanoes most often are found near subduction zones. They can be found at either oceanic-oceanic convergent plate boundaries, oceanic-continental plate boundaries, or continental-continental plate boundaries. They are especially prevalent in the Pacific Ring of Fire. A few composite volcanoes, however, have been found at divergent boundaries and away from plate boundaries at hot spots.
Volcanoes are most often found along plate boundaries. Here, conditions cause rocks in the upper mantle to melt, either by introducing volatiles or by reducing pressure.
Earthquakes occur most often along the boundaries of tectonic plates.
At this type of convergent boundary the oceanic plate will be subducted, or sink into the mantle underneath the continental plate. Volcanoes often form near these boundaries.
A reverse fault is often found at convergent plate boundaries.
Volcanoes are distributed as they are because most occur at the boundaries of the world's tectonic plates. Subducted crust rises as magma at constructive or destructive plate boundaries, and escapes through vents in the crust, often forming volcanoes on the surface. The only exceptions to volcanoes at plate boundaries are what are known as "hot-spot" volcanoes, that occur where a particular section of the Earth's crust is very thin and being heated by the mantle below. An example of this would be the Hawaiian Islands.
They can be associated with both, but are most often found near convergent boundaries.