sentence: The Pacific plate is subducted above the Mariana Plate, creating the Mariana trench, and (further on) the arc of the Mariana islands, as water trapped in the plate is released and explodes upward to form island volcanoes.
modified: fix grammar: The Pacifics plates is subducted above the Marianas Plates, creating the Marianas trenches, and (further on) the arcs of the Marianas island, as water trapped in the plates is released and explodes upward to form islands volcano.