Oceanic-oceanic refers to the interaction between two oceanic tectonic plates. When these plates converge, one plate may be forced beneath the other in a process called subduction. This can lead to the formation of deep ocean trenches and volcanic island arcs. An example of oceanic-oceanic interaction is the boundary between the Pacific Plate and the Philippine Sea Plate. As these plates collide, they create the Mariana Trench, the deepest part of the world's oceans, and the Mariana Islands, which are volcanic in origin.