Atlantic and Gulf of Mexico Submarine Landslides-Tsunami Hazards Project

Science Center Objects

Submarine landslides and tsunamis along the U.S. Atlantic and Gulf of Mexico coasts are rare, but the risks associated with these natural hazards are high. While most earthquakes in these margins are low in magnitude, and so shaking from them is not intense, they can still cause a lot of damage. The Atlantic and Gulf of Mexico margins are heavily urbanized, support extensive port and industrial/resource facilities, and host 10 nuclear power plants. With just enough earthquake shaking, unstable seafloor conditions can result in landslides that in turn trigger tsunamis.

satellite image caption: One of the Expedition 40 crew members aboard the International Space Station photographed this nighttime image showing city lights in at least half a dozen southern states from some 225 miles above the home planet. Lights from areas in the Gulf Coast states of Texas, Louisiana, Mississippi and Alabama, as well as some of the states that border them on the north, are visible. (Photo Credit: NASA)

U.S. east coast preliminary interpretations of large submarine landslides

Preliminary interpretation of large submarine landslide complexes, major submarine fans, and contourite drifts along the U.S. east coast.

(Public domain.)

It is challenging to determine the probability of occurrence of a tsunami or submarine landslide, as well as its location and scale. To that end, the CMHRP has completed quantitative assessments of submarine landslides for the U.S. Atlantic coast from Maine to Florida and throughout the Gulf of Mexico. Using existing geophysical and geological data complemented by newly collected sediment cores and high-resolution seafloor mapping/subsurface imaging data, the CMHRP constructed a database of submarine landslide locations, dimensions, morphology, and age that provide the basis for modeling potential landslide hazards. The database also allows examination of the roles various long- and short-term environmental processes (e.g., atmospheric conditions, shallow and deep water oceanographic regimes, sea level variations, sediment supply, and external triggering mechanisms like earthquakes) play in submarine landslide potential. The database is being used to inform policymakers and the general public on the potential risks that these marine geohazard phenomena pose.

These geologic assessments of submarine landslide hazards are combined with evaluations of the likelihood and characteristics of other hazards such as earthquakes, volcanic eruptions, and subaerial landslides carried out by programs within the USGS. Such CMHRP studies provide the basis for qualitative and probabilistic tsunami hazard analyses conducted in cooperation with partners in the USGS earthquake program, the NOAA Center for Tsunami Research, the National Tsunami Hazard Mitigation Program, the U.S. Nuclear Regulatory Commission, and academic partners.

satellite image caption: One of the Expedition 40 crew members aboard the International Space Station photographed this nighttime image showing city lights in at least half a dozen southern states from some 225 miles above the home planet. Lights from areas in the Gulf Coast states of Texas, Louisiana, Mississippi and Alabama, as well as some of the states that border them on the north, are visible. (Photo Credit: NASA)

Screen shot of a tsunami forecast model

Pacific Tsunami Warning Center scientists used their tsunami forecast model, RIFT, to simulate how a weather-generated tsunami, or meteotsunami, may have propagated off of the east coast of the United States in the North Atlantic Ocean on June 13, 2013.

(Public domain.)