Everything

Has a tsunami ever affected the United States? Yes… just last week.

Chaos Theory

Manmade and natural events can change important characteristics of U.S. waterways, ports, and harbors, and investigating those changes are an important responsibility for NOAA’s Office of Coast Survey. Following last week’s tsunami, Coast Survey’s staff and equipment on the West Coast are assisting with detection of submerged debris in critical marine transportation arteries along the coast.

The tsunami left the port at Crescent City, Calif., in a shambles, with marine debris and wreckage above and below the waterline. The U.S. Army Corps of Engineers asked Coast Survey to assist with hydrographic survey support there, to help make sure commercial and recreational vessels can begin to navigate safely and efficiently once again.

The U.S. Coast Guard and the Army Corp of Engineers also asked Coast Survey to survey the federal channel at Santa Cruz, Calif., which also experienced extensive damage and destruction to boats.

Coast Survey staff and navigation response teams have deployed to both port areas, and are coordinating with USCG and USACE to begin the hydrographic surveys.

Using a small boat equipped with powerful echo-sounding SONAR equipment, the teams will search the seafloor for sunken vessels, debris, and other hazards dangerous to commercial shippers and recreational boaters. The teams will also check the areas for shoaling. If the teams find shoaling, they will measure the bathymetry for updating NOAA’s nautical charts of the areas.

The Coast Survey navigation manager based in California is coordinating rapid response survey requests and navigational resources from areas impacted by last week’s tsunami.

Flooding From Tsunami

Japan's Coast Before the Earthquaker

NASA’s Terra satellite’s first view of northeastern Japan in the wake of a devastating earthquake and tsunami reveal extensive flooding along the coast. The Moderate Resolution Imaging Spectroradiometer (MODIS) acquired the top image of the Sendai region on March 12, 2011, at 10:30 a.m. The lower image, taken by Terra MODIS on February 26, 2011, is provided as a point of reference.

Water is black or dark blue in these images. It is difficult to see the coastline in the March 12 image, but a thin green line outlines the shore. This green line is higher-elevation land that is above water, presumably preventing the flood of water from returning to the sea. The flood indicator on the lower image illustrates how far inland the flood extends.

Both images were made with infrared and visible light, a combination that increases the contrast between muddy water and land. Plant-covered land is green, while snow-covered land is pale blue. Clouds are white and pale blue. The paved surfaces in the city of Sendai colors it brown.

MODIS detected a fire burning near the shore north of Sendai. The fire is marked with a red box. It is also surrounded by floods.

The photo-like true-color image acquired a few hours later shows plumes of sediment washed into the ocean along the coast and a dark plume of smoke near Sendai. Both images are from the MODIS Rapid Response System, which provides twice-daily images of Japan.

NASA images courtesy the MODIS Rapid Response Team at NASA GSFC. Caption by Holli Riebeek.

Instrument: Terra – MODIS