How Deep is the Puerto Rico Trench? 5.2 Miles Deep
In the early 2000s, scientists discovered a mud volcano in the Puerto Rico Trench that blasts saturated mud. The volcano is located at a depth of 4.9 miles (7,900 m).
Just forty-five miles of sea separate the U.S. Virgin Islands and Puerto Rico. Puerto Rico and the USVI sit atop towering submarine seamounts. If you drained the ocean around each island in the Caribbean archipelago, you’d be looking down from an enormous mountain.
A Massive Trench
The Puerto Rico Trench runs north of Puerto Rico, the USVI, and the British Virgin Islands. This submarine trench is home to the deepest point in the Atlantic Ocean. It’s also where the Caribbean Plate and the North American Plate meet, forming a subduction zone in which the North American Plate sinks beneath the Caribbean Plate.
The subduction zone is dramatic, with similarities to the Cascadia subduction zone that runs through California and the Pacific Northwest.
The Puerto Rico Trench is so extreme, that it ranks as the most negative gravity anomaly on Earth, -380mGal, a measurement researchers believe indicates the presence of an active downward force.
Mud Volcano and Tsunamis
The trench boasts one of the deepest submarine drop-offs in the region. Earthquakes occur every day throughout the Caribbean Plate.
In the early 2000s, scientists discovered a mud volcano in the Puerto Rico Trench that blasts saturated mud. The volcano is located 4.9 miles deep (a depth of 7,900 m). At the time, researchers said that despite posing a potential hazard to Puerto Rico and the Virgin Islands, the trench remained mostly unstudied.
Over 4 million U.S. citizens live on these islands, mostly along the coast.
The North American plate descends into the trench, is broken into steps with vertical offsets, and is sheared parallel to the trench.
In October 1918, a magnitude 7.2 earthquake originating in the Mona Passage, 98 miles west of the big island, struck Puerto Rico. The seismic event triggered a tsunami that struck Puerto Rico and Hispaniola, killing or injuring more than 100 people.
Researchers continue to study the trench to understand how subduction zones work and how often they produce megathrust quakes that trigger tsunamis.