Newly-acquired multibeam bathymetry of the entire Puerto Rico trench reveals numerous retrograde slope failures at various scales at the edge of the carbonate platform north of Puerto Rico and the Virgin Islands. The slumped material comprises carbonate blocks, which are cohesive and the edge of the carbonate platform is steeper than most continental slopes, resulting in a higher potential runup than along other U.S. coasts.
The style of sliding (rock falls and slide blocks vs. Debris avalanche and debris flow) appears to be correlated with the thickness of the carbonate layers at the headwall of the slide. Fissures, discovered in the ocean floor near the edge of the platform, indicate that the process is expected to continue in the future. Large submarine slides were discovered for the first time also on the northern side of the Puerto Rico trench. One of the slope failures, the Arecibo amphitheater, previously thought to represent a single giant slide with a volume of 900-1500 cu. km, appears to comprise several different slides. The expected maximum runup on the northern coast of Puerto Rico from one of these slides is <20 m, much lower than previously estimated. Although at larger depths (~6000 m), they aim toward Puerto Rico and have large horizontal and vertical dimensions. A 22-km wide slide scarp was discovered in the Upper Mona rift and could be associated with the 1918 tsunami and Earthquake that hit northwestern Puerto Rico.
Below are other science projects associated with this project.
Caribbean Tsunami and Earthquake Hazards Studies
Caribbean Tsunami and Earthquake Hazards Studies- Models
Caribbean Tsunami and Earthquake Hazards Studies- Stress Changes and Earthquake Hazard
Caribbean Tsunami and Earthquake Hazards Studies- Seafloor Map
- Overview
Newly-acquired multibeam bathymetry of the entire Puerto Rico trench reveals numerous retrograde slope failures at various scales at the edge of the carbonate platform north of Puerto Rico and the Virgin Islands. The slumped material comprises carbonate blocks, which are cohesive and the edge of the carbonate platform is steeper than most continental slopes, resulting in a higher potential runup than along other U.S. coasts.
The style of sliding (rock falls and slide blocks vs. Debris avalanche and debris flow) appears to be correlated with the thickness of the carbonate layers at the headwall of the slide. Fissures, discovered in the ocean floor near the edge of the platform, indicate that the process is expected to continue in the future. Large submarine slides were discovered for the first time also on the northern side of the Puerto Rico trench. One of the slope failures, the Arecibo amphitheater, previously thought to represent a single giant slide with a volume of 900-1500 cu. km, appears to comprise several different slides. The expected maximum runup on the northern coast of Puerto Rico from one of these slides is <20 m, much lower than previously estimated. Although at larger depths (~6000 m), they aim toward Puerto Rico and have large horizontal and vertical dimensions. A 22-km wide slide scarp was discovered in the Upper Mona rift and could be associated with the 1918 tsunami and Earthquake that hit northwestern Puerto Rico.
Sources/Usage: Public Domain.Perspective view of the edge of the carbonate platform. Viewing direction is from the NE to the SW. White arrows point to the boundary between multibeam bathymetry and single-beam bathymetry. Black arrows point to fissures in the seafloor. Dotted lines are debris toes. The locations of a previously suggested strike-slip fault (SPRSFZ) and the largest free-air gravity anomaly on Earth (-380 mGal) are shown. Stippled textures (e.g., near SPRSFZ) are multibeam acquisition artifacts. - Science
Below are other science projects associated with this project.
Caribbean Tsunami and Earthquake Hazards Studies
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. Plate movements have caused large magnitude earthquakes and devastating tsunamis. The USGS has an ongoing program to identify and map the faults in this region using various geophysical and geological methods in order to estimate the location...Caribbean Tsunami and Earthquake Hazards Studies- Models
The Puerto Rico trench exhibits great water depth, extremely low gravity anomaly, and a tilted carbonate platform between (reconstructed) elevations of +1300 m and -4000 m. we suggest that these features are manifestations of large vertical movements of a segment of the Puerto Rico Trench, its forearc, and the island of Puerto Rico that took place 3.3 m.y. ago over a time period as short as 14-40...Caribbean Tsunami and Earthquake Hazards Studies- Stress Changes and Earthquake Hazard
Strike-slip faults in the forearc region of a subduction zone often present significant seismic hazard because of their proximity to population centers. We explore the interaction between thrust events on the subduction interface and strike-slip faults within the forearc region using 3-D models of static Coulomb stress change.Caribbean Tsunami and Earthquake Hazards Studies- Seafloor Map
To help understand the origin of the unusual bathymetry, gravity, and vertical tectonics of the plate boundary and to provide constraints for hazard assessment, the morphology of the entire 770-km-long trench from the Dominican Republic in the west to Anguilla in the east was mapped with multibeam echosounder during three cruises in 2002 and 2003. Parts of the Puerto Rico Trench were previously...