In 2002 and 2003, the National Oceanic and Atmospheric Administration (NOAA) conducted a major research study of the Puerto Rico Trench. Situated just north of the Commonwealth of Puerto Rico, the Puerto Rico Trench separates the Atlantic Ocean and the Caribbean Sea.

The ocean trench is a geologically complex site. The Caribbean and North American tectonic plates are scraping by each other, making a huge transform fault that extends from the Puerto Rico Trench to the coast of Central America. The Caribbean plate is shifting east, while the North American plate is shifting west.

In addition to the transform fault, the Puerto Rico Trench is also associated with a subduction zone. To the trench's east, the heavy North American plate, which carries the northern Atlantic Ocean as well as the continent of North America, is being subducted beneath the smaller Caribbean plate.