Reconnaissance report on damage in and around river levees caused by the 2011 off the Pacific coast of Tohoku earthquake

Sasaki, Yasushi; Towhata, Ikuo; Miyamoto, Kenya; Shirato, Masami; Narita, Akiyoshi; Sasaki, Tetsuya; Sako, Shunsuke

doi:10.1016/j.sandf.2012.11.018

Cited by 45 publications

(13 citation statements)

References 6 publications

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“…Hazarrika et al [9] reported major damage to river embankments during the backrush: "the overflowing tsunami while retreating made a concentrated attack on the weak part of the structure". Sasaki et al [28] similarly reported significant erosion of river dykes upon retreat of the tsunami water. Tanaka et al [32] discussed the drainage of river courses during the retreating tsunami phases.…”

Section: Discussionmentioning

confidence: 98%

Unsteady turbulence in expansion waves in rivers and estuaries: an experimental study

Leng

Chanson

2014

Environ Fluid Mech

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A sudden decrease in water depth, called a negative surge or expansion wave, is characterised by a gentle change in free-surface elevation. Some geophysical applications include the ebb tide flow in macro-tidal estuaries, the rundown of swash waters and the retreating waters after maximum tsunami runup in a river channel. The upstream propagation of expansion waves against an initially steady flow was investigated in laboratory under controlled flow conditions including detailed free-surface velocity and Reynolds stress measurements. Both non-intrusive free-surface measurements and intrusive velocity measurements were conducted for relatively large Reynolds numbers with two types of bed roughness. The data showed that the propagation of expansion waves appeared to be a relatively smooth lowering to the water surface. The wave leading edge celerity data showed a characteristic trend, with a rapid acceleration immediately following the surge generation, followed by a deceleration of the leading edge surge towards an asymptotical value: (U+V o )/(g×d o ) 1/2 = 1 for both smooth and rough bed experiments. The results indicated that the bed roughness had little to no effect, within the experimental flow conditions. Relatively large fluctuations in freesurface elevation, velocity and turbulent shear stress were recorded beneath the leading edge of the negative surge for all flow conditions. The instantaneous turbulent shear stress levels were significantly larger than the critical shear stress for sediment erosion. The present results implied a substantial bed erosion during an expansion wave motion.

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Section: Discussionmentioning

confidence: 98%

Unsteady turbulence in expansion waves in rivers and estuaries: an experimental study

Leng

Chanson

2014

Environ Fluid Mech

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“…Small liquefiable lenses surrounded by non-liquefiable soils may result in negligible deformations, whereas large, spatially-continuous liquefiable zones will likely cause significant deformations. Earthquake-induced liquefaction has caused levee deformations during past earthquakes in various locations around the world (though not in the Delta) (Miller and Roycroft 2004;Sasaki 2009;Green et al 2011;Sasaki et al 2012;Kwak et al 2016a). …”

Section: Seismic Threats To Leveesmentioning

confidence: 99%

Factors and Processes Affecting Levee System Vulnerability

Deverel¹,

Bachand²,

Brandenberg³

et al. 2016

SFEWS

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We appraised factors and processes related to human activities and high water, subsidence, and seismicity. Farming and drainage of peat soils caused subsidence, which contributed to levee internal failures. Subsidence rates decreased with time, but still contributed to levee instability. Modeling changes in seepage and static slope instability suggests an increased probability of failure with decreasing peat thickness. Additional data is needed to assess the spatial and temporal effects of subsidence from peat thinning and deformation. Large-scale, state investment in levee upgrades (> $700 million since the mid-1970s) has increased conformance with applicable standards; however, accounts conflict about corresponding reductions in the number of failures.Modeling and history suggest that projected increases in high-flow frequency associated with climate change will increase the rate of levee failures. Quantifying this increased threat requires further research. A reappraisal of seismic threats resulted in updated ground motion estimates for multiple faults and earthquake-occurrence frequencies. Estimated ground motions are large enough to induce failure. The immediate seismic threat, liquefaction, is the sudden loss of strength from an increase in the pressure of the pore fluid and the corresponding loss of inter-particle contact forces. However, levees damaged during an earthquake that do not immediately fail may eventually breach. Key sources of uncertainty include occurrence frequencies and magnitudes, localized ground motions, and data for liquefaction potential.Estimates of the consequences of future levee failure range up to multiple billions of dollars. Analysis of future risks will benefit from improved description of levee upgrades and strength as well as consideration of subsidence, the effects of climate change, and earthquake threats. Levee habitat ecosystem benefits in this highly altered system are few. Better recognition and coordination is needed among the creation of high-value habitat, levee needs, and costs and benefits of levee improvements and breaches.

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“…Because a more detailed report has been written (Sasaki et al, 2012), the present text picks up only one example of engineering importance. The Himuma Lake is connected to the mouth of Naka River in the Northern Kanto Region (Fig.…”

Section: Liquefaction In Levee Of Hinuma Lakementioning

confidence: 99%

Liquefaction in the Kanto region during the 2011 off the pacific coast of Tohoku earthquake

Towhata

Maruyama

Kasuda³

et al. 2014

Soils and Foundations

Self Cite

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The present text is a summary of liquefaction events that occurred in the Kanto Region during the 2011 off the Pacific coast of Tohoku Earthquake, excluding those events in the Tokyo Bay area that are discussed elsewhere. Most liquefaction occurred in the abandoned river channels and former lakes that had been recently filled with liquefiable soils. Noteworthy was the damage to private housing lands and river dikes that had not been well treated against liquefaction risk. Many sites experienced repeated liquefaction after former earthquakes in 1923 or 1987, if they existed in those times. In contrast to the recent liquefaction-prone soils, more-aged sands scarcely liquefied because of what is called the "ageing" effect. The present study analyzed cases in Tokyo area to quantitatively assess the temporal development of ageing so that liquefaction risk in more aged soils might be reasonably assessed. In the appendix, remarks are made of the reliability of air-photo survey in quick detection of liquefaction sites.

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Reconnaissance report on damage in and around river levees caused by the 2011 off the Pacific coast of Tohoku earthquake

Cited by 45 publications

References 6 publications

Unsteady turbulence in expansion waves in rivers and estuaries: an experimental study

Unsteady turbulence in expansion waves in rivers and estuaries: an experimental study

Factors and Processes Affecting Levee System Vulnerability

Liquefaction in the Kanto region during the 2011 off the pacific coast of Tohoku earthquake

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