Figure 14: Locality map for the Izu-Bonin-Mariana arc system. The IBM arc system shows tremendous variations in tectonic style and morphologic expression, from collision with Japan in the north to the greatest deep in the world, the Challenger Deep, in the south. The Mariana Trough is an actively spreading backarc basin and the Mariana forearc contains the only sites of active serpentine diapirism and fluid egress through a forearc. The detailed crustal section shown in Figure 9 is from the northern part of this arc system.