scholarly journals SEISMIC BEHAVIOR OF THE TOKYO BAY AREA DURING THE 2011 OFF THE PACIFIC COAST OF TOHOKU EARTHQUAKE USING DOWNHOLE ARRAY RECORDS

2012 ◽  
Vol 68 (4) ◽  
pp. I_138-I_151
Keyword(s):  
Seismic Behavior ◽  
Pacific Coast ◽  
Tohoku Earthquake ◽  
Tokyo Bay ◽  
Bay Area ◽  
The Pacific ◽  
Downhole Array

scholarly journals Subsidence by liquefaction-fluidization in man-made strata around Tokyo bay, Japan: from geological survey on damaged part at the 2011 off the Pacific Coast of Tohoku Earthquake

2015 ◽  
Vol 372 ◽  
pp. 221-226
Author(s):  
O. Kazaoka ◽  
S. Kameyama ◽  
K. Shigeno ◽  
Y. Suzuki ◽  
M. Morisaki ◽  
...  
Keyword(s):  
Pacific Coast ◽  
Tohoku Earthquake ◽  
Geological Survey ◽  
Japan Meteorological Agency ◽  
Tokyo Bay ◽  
Great Earthquake ◽  
Reclaimed Land ◽  
Chiba Prefecture ◽  
Detailed Classification ◽  
The Pacific

Abstract. Geological disaster by liquefaction-fluidization happened on southern part of the Quaternary Paleo-Kanto submarine basin at the 2011 Earthquake off the Pacific Coast of Tohoku. Liquefaction-fluidization phenomena occurred mainly in man-made strata over shaking 5+ intensity of Japan Meteorological Agency scale. Many subsided spots, 10–50 m width, 20–100 m length and less than 1 m depth, by liquefaction-fluidization distributed on reclaimed land around northern Tokyo bay. Large amount of sand and groundwater spouted out in the terrible subsided parts. But there are little subsidence and no jetted sand outside the terrible subsided part. Liquefaction-fluidization damaged part at the 1987 earthquake east off Chiba prefecture re-liquefied and fluidized in these parts at the 2011 great earthquake. The damaged area were more wide on the 2011 earthquake than the 1987 quake. Detailed classification maps of subsidence by liquefaction-fluidization on the 2011 grate earthquake were made by fieldwork in Chiba city around Tokyo bay. A mechanism of subsidence by liquefaction-fluidization in man-made strata was solved by geological survey with continuous large box cores on the ACE Liner and large relief peals of the cores at a typical subsided part.

Performance of Piled Raft Foundation with Grid-Form Ground Improvement During the 2011 off the Pacific Coast of Tohoku Earthquake

2012 ◽  
Vol 7 (6) ◽  
pp. 726-732 ◽  
Author(s):  
Akihiko Uchida ◽  
◽  
Kiyoshi Yamashita ◽  
Nobuyuki Odajima ◽  
Keyword(s):  
Pacific Coast ◽  
Simulation Analysis ◽  
Ground Improvement ◽  
Tohoku Earthquake ◽  
Field Investigation ◽  
Soil Liquefaction ◽  
Tokyo Bay ◽  
Reclaimed Land ◽  
Piled Raft Foundation ◽  
The Pacific

Grid-form ground improvement by the deep cement mixing method is one of the countermeasures against soil liquefaction. Improvements by this method were confirmed during the southern Hyogo Prefecture Earthquake in 1995. The number of building foundations adopting this method has increased in the last years. During the 2011 off the Pacific coast of Tohoku Earthquake, which occurred on March 11, severe liquefaction damage was observed in reclaimed land in the Tokyo Bay area. Since then, liquefaction countermeasures have been recognized to be important to reclaimed land. A building foundation improved by grid-form ground improvement method is introduced in this paper. Field investigation results of ground around the building after the 2011 earthquake are presented. The effect of liquefaction prevention on gridform ground improvement is discussed based on dynamic nonlinear analysis of soil layers with actual acceleration records. Comparing field investigation results to simulation analysis, we concluded that gridform ground improvement prevented liquefaction of original soil surrounded by grid-form walls during the 2011 earthquake.

scholarly journals Maps of soil subsidence for Tokyo bay shore areas liquefied in the March 11th, 2011 off the Pacific Coast of Tohoku Earthquake

2013 ◽  
Vol 53 ◽  
pp. 240-253 ◽  
Author(s):  
Kazuo Konagai ◽  
Takashi Kiyota ◽  
Shota Suyama ◽  
Toru Asakura ◽  
Kenichi Shibuya ◽  
...  
Keyword(s):  
Pacific Coast ◽  
Tohoku Earthquake ◽  
Tokyo Bay ◽  
Soil Subsidence ◽  
The Pacific
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