Caption: "A cross section cartoon of the Mariana Trench depicting main structures and features." (Slightly edited.)

Caption 2: "The Pacific plate is subducted beneath the Mariana Plate, creating the Mariana Trench, and (further on) the arc of the Mariana islands, as water trapped in the tectonic plate is released and explodes upward to form island volcanoes." (Slightly edited from Wikipedia: Mariana Trench.)

Credit/Permission: © D.M. Hussong & P. Fryer, (1981), Vanessa Ezekowitz (AKA User:Vanessaezekowitz), 2009 / Creative Commons CC BY-SA 3.0.
Image link: Wikipedia: File:Cross section of mariana trench.svg.
Local file: local link: mariana_trench.html.
File: Earth geology file: mariana_trench.html.