The main issues: the volcanoes and earthquakes are a result of the tectonic boarders: where there is a hole between the plates, volcanoes rise. And where the plates move towards and along each other, this causes vibrations. 

The Ring of Fire is a direct consequence of plate tectonics (shape of the plates) and the movement and collisions of these plates. For instance the eastern section of the ring is the result of the Nazca Plate and the Cocos Plate being pressed beneath the westward moving South American Plate. And there are a lot of other contacts with plates along the Ring of Fire. The southern part of the Ring of Fire is the most complex part, here there are collisions between a number of smaller tectonic plates and the Pacific plate from the Mariana Islands, the Philippines, Bougainville, Tonga, and New Zealand.