Liquefaction damages in the Osaki plain, Miyagi Prefecture caused by the 2011 off the Pacific coast of Tohoku EarthquakeLiquefaction damages in the Osaki plain, Miyagi Prefecture caused by the 2011 off the Pacific coast of Tohoku EarthquakeAA00200173
40 , 2016 , Department of Geography, Tokyo Metropolitan University
Extensive liquefaction-induced damages caused by the 2011 off the Pacific coast of Tohoku Earthquake were observed in the Osaki plain, northern part of Miyagi Prefecture. A large number of sand boils were detected in the former river channels, natural levees and refilled gravel pits along the Eai and Naruse rivers. However, sand boils in the study area sparsely occurred rather than the Tone river lowland, Kanto Region. Many liquefaction damages such as uplift of underground structures, subsidence of road surfaces along the sewage line and settlement of ground around building were observed in the central area of Osaki City. This area is located in the back marsh and developed on the paddy fields since the 1970’s, and liquefaction damages tended to be observed in the back marsh (clayey or peaty ground) rather than on the natural levee (sandy ground). Significant damages of the sewage manholes were observed in the clayey or peaty ground. Settlement and tilt of house due to the liquefaction were observed at only a few sites.