Caribbean Tsunami and Earthquake Hazards Studies

Narrator: In a new method called ‘multibeam’, the ship sends and receives simultaneously 120 narrow acoustic beams at different angles, allowing us to accurately map sections of the seabed up to 10 kilometers wide.

The sound beams are sent and received by this attachment under the keel of the boat. The data is processed aboard the ship.

(Background voices from technicians processing the data)
One Technician (unseen): Delete one right there!
(Background voices from technicians processing the data)

Narrator: The result of the data processing is a highly detailed, three-dimensional map of the Puerto Rico Trench and the surrounding area.

On the right, the gray is Puerto Rico. The deepest sea floor is in purple. Shallow under water areas are in red. The bottom of the Puerto Rico trench is nearly 28,000 feet or 8,350 meters below sea level, the deepest part of the Atlantic Ocean. If you could drop Mount Everest into the bottom of the trench, its peak would just form a hill above the water.

Why is the Puerto Rico trench the deepest place in the Atlantic Ocean, and why is Puerto Rico an island? This is a view of the trench, the island, the Lesser Antilles, Hispaniola, Cuba, the Bahamas Banks, and Florida in the upper right.

The North American tectonic plate on the top right sinks into the earth mantle under the Lesser Antilles, Puerto Rico, and Hispaniola. This subduction, or sinking, happens at the trench causing many earthquakes.