March 15, 2011
A new before-and-after image pair from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA’s Terra spacecraft shows a region of Japan‘s northeastern coast, northeast of the city of Sendai, which was affected by the March 11, 2011 tsunami.
The images show the coastal cities of Ofunato and Kesennuma, located about 90 kilometers (55 miles) northeast of Sendai. Ofunato has a population of about 42,000, while the population of Kesennuma is about 73,000. Areas covered by vegetation are shown in red, while cities and unvegetated areas are shown in shades of blue-gray. The image on the left was acquired on March 14, 2011; the image on the right was acquired in August 2008. When compared closely, vegetation is no longer visible in many coastal areas in the new image, particularly around Kesennuma. Scientists believe this is most likely due to the effects of the tsunami.
The images show an area located at 39.4 degrees north latitude, 141.9 degrees east longitude, and cover an area of 28 by 46 kilometers (17 by 27 miles).
In the wake of the magnitude 9.0 earthquake and resulting tsunami that struck northeastern Japan in March 2011, ocean waters flooded croplands and settlements lining the Kitakami River. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA’s Terrasatellite captured these false-color images before and after the tsunami. The top image is from March 14, 2011, and the bottom is from January 16, 2011.
The images combine infrared, red, and green wavelengths of light to form a false-color image that distinguishes between water and land. Water is blue. Buildings and paved surfaces appear in shades of blue-gray. Fallow fields appear in shades of beige and brown. Vegetation is red, and the brighter the red, the more robust the vegetation. (Brighter shades of red in March and duller shades in January result largely from the difference in season.)
In the March image, water has spilled over the banks both north and south of the river. Although agricultural fields appear to have escaped the flooding farther inland (image left), some fields closer to the ocean have seemingly disappeared into the sea. North of the Kitakami, floodwaters extend far enough inland to create what looks like a parallel river. Near the coast, only the rugged peaks rising above the floodplains have escaped inundation. Floating debris from the tsunami has accumulated in several coves (particularly image lower right).
On March 15, 2011 (early on March 16 in Japan), NHK World reported that the number of dead and missing likely exceeded 10,000. While police reported 3,373 confirmed deaths, 7,558 people remained missing. More than 440,000 people had sought refuge in temporary shelters.