a floor of Cocos, Nazca and Caribbean plates. Moving Northeast at 10 cm/year, the Cocos plate is subducted beneath the Caribbean plate resulting in the volcanism. From this same image Jeff Marshall has noted the boundary between the smooth sea floor associated with the Cocas plate and the rough elevation below sea (Nazca plate) that bounds to the southeast. Shown lower left is the boundary of the Middle America Trench (purple) off shore of Nicaragua and Costa Rica's Nicoya Peninsula. The Trench is even more dramatic in 3-D from the perspective looking East at the subduction zone (image lower right). 
