When an oceanic plate and a continental plate converge, the oceanic plate slips under the continental plate in a region called the subduction zone . Oceanic plate bends downward, producing an oceanic trench . The deepest known place in the ocean is Challenger Deep in the Mariana Trench . The subducted plate partially melts to form magma. Magma rises to surface of the land, resulting in volcanic activity.
Volcanic activity produces mountain ranges called volcanic arcs .
As the oceanic plate subducts, sections of rock hang up but eventually shatter. This produces earthquakes along the plane of the subducting plate. This region is called the Benioff zone . One oceanic plate subducts under the other. The results are similar to the phenomena observed with oceanic-continental convergence, but volcanoes form on the sea floor.