If you look at the U.S. Nuclear Regulatory Commission’s interactive map of nuclear power plants in the United States, you will see several in states bordering the Atlantic Ocean. This prompted the Nuclear Regulatory Commission to request the U.S. Geological Survey (USGS), along with other governmental and academic partners, to research the potential for tsunamis to strike the U.S. Atlantic and Gulf of Mexico coasts, and prepare maps using sonar (originally an acronym for SOund Navigation And Ranging). Note that the March 11, 2011 earthquake near Honshu, Japan, created a tsunami that resulted in a nuclear disaster that is still being remediated.
Courtesy National Oceanic and Atmospheric AdministrationThrough this research, initiated about five years ago, the leading potential source of dangerous tsunamis to the East Coast was identified as landslides, either originating in submarine canyons or on the continental slope of the submerged margin of the continent of North America.
According to USGS marine geologist Jason Chaytor, many years of data collection and integration of existing data sets was needed in order to produce seafloor maps with the resolution needed to identify all of the relevant features for this study. The first field effort of this project was a multibeam bathymetric mapping cruise conducted aboard the National Oceanic and Atmospheric Administration (NOAA) Ship Nancy Foster from June 4 to June 16, 2011. Using echosounders installed on the hull of Nancy Foster, the science team mapped canyons and shelf regions at high resolution over more than 380 square miles (1,000 square kilometers) of seafloor from south of Cape Hatteras, located offshore of North Carolina, to the eastern tip of Long Island in New York.
Courtesy United States Geological Survey
A number of submarine landslides, some previously unknown, were either partly or completely mapped. Characteristics collected include the size and number of landslides, soil and rock properties, the water depth they occur in, and the style in which they fail. This information is often used in numerical modeling of tsunamis generated by landslides.
The scientists detailed their findings in the September/October issue of the USGS newsletter Sound Waves.
See photographs of the Japan earthquake/tsunami damage on Gigapan. (You can zoom and pan to explore each image.)
Check out this amazing map. It shows the number of foreshocks, the big quake, and aftershocks, as well their location, date/time, depth, and magnitude. Stick with it: it starts off slowly, but it gets pretty horrifyingly spectacular.