The island sits where the Caribbean Plate meets the North American Plate, an area that can be very active.

Plate movements have caused large magnitude earthquakes and devastating tsunamis. Puerto Rico and the Virgin Islands are located at an active plate boundary between the North American plate and the northeast corner of the Caribbean plate. The highly oblique Puerto Rico subduction is associated with ≤ 5 mm/yr of plate boundary–normal convergence and is found to be uncoupled, hence transmitting little stress to the upper plate. Geology of Puerto Rico An Overview of the Plate Tectonic Origin of the Caribbean Slide 2 Outline • Rock types in Puerto Rico • Plate Tectonics review • Puerto Rico formed WHERE?

Here's how plate tectonics caused Puerto Rico's recent earthquakes. • Evidence • Tectonic Reconstruction . The major earthquakes in Puerto Rico and Haiti, as well as eruptions on Montserrat are all reminders that complex interactions between tectonic plates lie along the Caribbean Ocean's margins. The Northern Caribbean Plate, as well as the Hispaniola microplate and Puerto Rico-Virgin Islands (PRVI) is generally moving NNE relative to the North American Plate but with slight variations in direction and rate (Mann, 2005a; ten Brink & López-Venegas, 2012; Benford et al., 2012). To the north of the island, a portion of the North American plate subducts obliquely beneath the Caribbean plate along the 1,090 kilometer-long Puerto Rico Trench. 2 Slide 3 Rocks for Astronomers Astronomy: … The Caribbean plate lies beneath much of the ocean of the same name (see below).
Puerto Rico Seismic Network, Geology Department, University of Puerto Rico at Mayagüez, P.O. Box 9017, Mayagüez, Puerto Rico 00681 Search for other works by this author on: GSW