The Pacific ocean basin is rimmed by the most subduction zones.
The Pacific Ocean is the largest and deepest of the world ocean basins. It is the oldest of the existing ocean basins dated back about 200 million years.
Pacific basin is referred to as the “Ring of Fire” due to intense earthquake and volcanic activity occurring near areas of tectonic plate subduction.
It covers approx. 63 million sq. miles, big enough to fit all 7 continents into it. It contains more than half of free water on Earth. [Source]