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Earthquake-induced soil displacements and their impact on rehabilitations.

Konagai K - Proc. Jpn. Acad., Ser. B, Phys. Biol. Sci. (2011)

Bottom Line: Therefore one of what required of us is to deduce as much hidden signs as possible from observable changes of landforms.An attempt was made to convert changes in elevation in Eulerian description for images obtained from remote-sensing technologies to Lagrangian displacements, because Lagrangian displacements can directly describe behaviors of soils, which are typically history-dependent.This paper documents some big pictures of earthquake-inflicted landform changes obtained through this attempt.

View Article: PubMed Central - PubMed

Affiliation: Institute of Industrial Science, The University of Tokyo, Japan. konagai@iis.u-tokyo.ac.jp

ABSTRACT
A large earthquake can trigger long lasting geotechnical problems, which pose serious issues on both rehabilitations and land conservations. Therefore one of what required of us is to deduce as much hidden signs as possible from observable changes of landforms. Though serious, damage caused by the October 23rd 2004, Mid-Niigata Prefecture Earthquake has given us a rare opportunity to study the landform changes in mountainous terrain hit by this earthquake. An attempt was made to convert changes in elevation in Eulerian description for images obtained from remote-sensing technologies to Lagrangian displacements, because Lagrangian displacements can directly describe behaviors of soils, which are typically history-dependent. This paper documents some big pictures of earthquake-inflicted landform changes obtained through this attempt.

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Related in: MedlinePlus

Inferred Lagrangian descriptions of (a) tectonic and (b) shallow displacements in Kizawa locality on the Japanese National Grid System, Zone VIII (see Appendix).
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fig11: Inferred Lagrangian descriptions of (a) tectonic and (b) shallow displacements in Kizawa locality on the Japanese National Grid System, Zone VIII (see Appendix).

Mentions: Referring back to past earthquakes, underground facilities and/or foundations closely follow the motions of their surrounding soils/rocks. Therefore, the problem at Kizawa was how large the shear plane had spread in the interior of the rock, and if the rock mass above the shear plane would move again in snow-melt seasons. Kizawa area, as shown by a square in Fig. 5(a), is within the NNE–SSW trending 1 to 2 km wide belt of large eastward tectonic movement to the west of and along the Kajigane syncline. Figure 11(a)is an enlarged view of this area showing that the entire area has shifted southeast. However, scaling down the window size for the moving-average method to a smaller square of 200 m × 200 m, a different image of soil movements appears reflecting shallower soil deformations. Therefore, the image of shallower soil deformation (Fig. 11(b)) was obtained by subtracting tectonic displacements vectors viewed through the larger moving window of 1 km × 1 km square from those through the smaller window of 200 m × 200 m square. In Fig. 11(b), soil masses on almost all sides of Futagoyama Mountain show 0.5 to 1 m downslope movements.


Earthquake-induced soil displacements and their impact on rehabilitations.

Konagai K - Proc. Jpn. Acad., Ser. B, Phys. Biol. Sci. (2011)

Inferred Lagrangian descriptions of (a) tectonic and (b) shallow displacements in Kizawa locality on the Japanese National Grid System, Zone VIII (see Appendix).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3313688&req=5

fig11: Inferred Lagrangian descriptions of (a) tectonic and (b) shallow displacements in Kizawa locality on the Japanese National Grid System, Zone VIII (see Appendix).
Mentions: Referring back to past earthquakes, underground facilities and/or foundations closely follow the motions of their surrounding soils/rocks. Therefore, the problem at Kizawa was how large the shear plane had spread in the interior of the rock, and if the rock mass above the shear plane would move again in snow-melt seasons. Kizawa area, as shown by a square in Fig. 5(a), is within the NNE–SSW trending 1 to 2 km wide belt of large eastward tectonic movement to the west of and along the Kajigane syncline. Figure 11(a)is an enlarged view of this area showing that the entire area has shifted southeast. However, scaling down the window size for the moving-average method to a smaller square of 200 m × 200 m, a different image of soil movements appears reflecting shallower soil deformations. Therefore, the image of shallower soil deformation (Fig. 11(b)) was obtained by subtracting tectonic displacements vectors viewed through the larger moving window of 1 km × 1 km square from those through the smaller window of 200 m × 200 m square. In Fig. 11(b), soil masses on almost all sides of Futagoyama Mountain show 0.5 to 1 m downslope movements.

Bottom Line: Therefore one of what required of us is to deduce as much hidden signs as possible from observable changes of landforms.An attempt was made to convert changes in elevation in Eulerian description for images obtained from remote-sensing technologies to Lagrangian displacements, because Lagrangian displacements can directly describe behaviors of soils, which are typically history-dependent.This paper documents some big pictures of earthquake-inflicted landform changes obtained through this attempt.

View Article: PubMed Central - PubMed

Affiliation: Institute of Industrial Science, The University of Tokyo, Japan. konagai@iis.u-tokyo.ac.jp

ABSTRACT
A large earthquake can trigger long lasting geotechnical problems, which pose serious issues on both rehabilitations and land conservations. Therefore one of what required of us is to deduce as much hidden signs as possible from observable changes of landforms. Though serious, damage caused by the October 23rd 2004, Mid-Niigata Prefecture Earthquake has given us a rare opportunity to study the landform changes in mountainous terrain hit by this earthquake. An attempt was made to convert changes in elevation in Eulerian description for images obtained from remote-sensing technologies to Lagrangian displacements, because Lagrangian displacements can directly describe behaviors of soils, which are typically history-dependent. This paper documents some big pictures of earthquake-inflicted landform changes obtained through this attempt.

Show MeSH
Related in: MedlinePlus