Land subsidence of clay deposits after the Tohoku-Pacific Ocean Earthquake

Proceedings of the International Association of Hydrological Sciences. 2015;372:211-216 DOI 10.5194/piahs-372-211-2015

 

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Journal Title: Proceedings of the International Association of Hydrological Sciences

ISSN: 2199-8981 (Print); 2199-899X (Online)

Publisher: Copernicus Publications

Society/Institution: International Association of Hydrological Sciences

LCC Subject Category: Geography. Anthropology. Recreation: Environmental sciences | Science: Geology

Country of publisher: Germany

Language of fulltext: English

Full-text formats available: PDF, XML

 

AUTHORS

K. Yasuhara (Institute for Global Change Adaptation Science, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki, 310-8512, Japan)
M. Kazama (Graduate School of Engineering, Tohoku University, 2-1-1 Katahira Aoba-ku Sendai-shi, Miyagi, 980-8577, Japan)

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Time From Submission to Publication: 12 weeks

 

Abstract | Full Text

Extensive infrastructure collapse resulted from the cataclysmic earthquake that struck off the eastern coast of Japan on 11 March 2011 and from its consequent gigantic tsunami, affecting not only the Tohoku region but also the Kanto region. Among the geological and geotechnical processes observed, land subsidence occurring in both coastal and inland areas and from Tohoku to Kanto is an extremely important issue that must be examined carefully. This land subsidence is classifiable into three categories: (i) land sinking along the coastal areas because of tectonic movements, (ii) settlement of sandy deposits followed by liquefaction, and (iii) long-term post-earthquake recompression settlement in soft clay caused by dissipation of excess pore pressure. This paper describes two case histories of post-earthquake settlement of clay deposits from among the three categories of ground sinking and land subsidence because such settlement has been frequently overlooked in numerous earlier earthquakes. Particularly, an attempt is made to propose a methodology for predicting such settlement and for formulating remedial or responsive measures to mitigate damage from such settlement.