The Pacific Realm has been called the “Pacific Ring of Fire” because it is an area of intense volcanic activity. More than 75% of the earth’s volcanoes are in this region. Since volcanoes are associated with lava and fire, the area comes to be called the “Ring of Fire.”
We should note that not all of the Pacific Realm is part of what is typically called the Ring of Fire. The term “Ring of Fire” is typically used to refer to the area around the rim of the Pacific Ocean. In other words, places like Hawaii and most of Micronesia are not typically included in the Ring of Fire.
The Pacific Ring of Fire is generally defined as the horseshoe-shaped region that runs from New Zealand up along the coast of Asia, and then around to and down the west coast of the Americas. This entire region is very seismically active because of the fact that there are subduction zones on both sides of the ocean. As various oceanic plates slide under continental plates, volcanoes arise.
For these reasons, much of the Pacific Realm is referred to as the Pacific Rim of Fire.