Identification of a Soil Liquefied Layer due to the 2011 off the Pacfic coast of Tohoku Earthquake Using X-ray CT Scan Imaging

The 2011 off the Pacfic coast of Tohoku Earthquake caused an unprecedented and widespread soil liquefaction event especially in the southern part of the Kanto district. An improved understanding of the complex liquefaction processes involved and especially identification of the liquefaction layer, is needed to understand and mitigate against such events. We report here for the first time the application of X-ray computerized tomography (CT) scanning to core samples of the soft and water-saturated near-surface formations subjected to liquefaction. Our results clearly show images of the different sedimentary units and their internal structure, including ripple laminations and load casts. One unit was identified where the original sedimentary structures have been completely obliterated, which we interpret to be the zone of liquefaction. Our results show that X-ray CT scanning is a potentially useful tool for soil liquefaction research in the fields of geology and engineering.