Why do destructive plate boundaries create violent earthquakes and volcanoes?
Mainly because of the angle of the converging plate into the other. When one plate collides into another it usually subducts underneath the plate, which causes uplift and many violent earthquakes. When it is an oceanic plate colliding into a continental plate, there is most likely, what we call, a subduction zone. Depending on the angle of the subduction, that determines how violent the activity on the continent. When the angle is great such as sloping at a 45 deg angle, or steeper from the continental crust rather than a 20 degree angle from the crust, you are likely to have a lot of volcanism. the more shallow the angle, the more the continental uplift vs. volcanism, and the steeper the angle, the more volcanism. This is because of the pressure it causes on the mantle and that pressure has to be relieved, in some way, so it bursts out of the Earth’s crust violently. At divergent plate boundaries, you also have volcanism, but these volcano types are the calmer more safer type. Hawaii
