- The 11 March 2011 East Japan Earthquake and Tsunami caused unprecedented
damage to well-engineered buildings and coastal structures. This report presents some notable
field observations of structural damage based on our surveys conducted along the Sanriku coast
in April and June 2011. Engineered reinforced concrete buildings failed by rotation due to the
high-velocity and deep tsunami inundation: entrapped air in the buildings and soil liquefaction
by ground shaking could have contributed to the failure. The spatial distribution pattern of
destroyed and survived buildings indicates that the strength of tsunami was affected significantly
by the locations of well-engineered sturdy buildings: weaker buildings in the shadow zone
tended to survive while jet and wake formations behind the sturdy buildings enhanced the
tsunami forces. We also found that buildings with breakaway walls or breakaway windows/doors
remained standing even if the surrounding buildings were washed away or destroyed. Several
failure patterns of coastal structures (seawalls) were observed. Flow-induced suction pressure
near the seawall crown could have caused the failure of concrete panels that covered the infill.
Remarkable destruction of upright solid-concrete type seawalls was closely related with the
tsunami induced scour and soil instability. The rapid decrease in inundation depth during the
return-flow phase caused soil fluidization down to a substantial depth. This mechanism explains
severely undermined roads and foundations observed in the area of low flow velocities.
- Yeh, H., Sato, S., & Tajima, Y. (2013). The 11 march 2011 East Japan earthquake and tsunami: Tsunami effects on coastal infrastructure and buildings. Pure and Applied Geophysics, 170(6), 1019-1031. doi:10.1007/s00024-012-0489-1
|Funding Statement (additional comments about funding)
- This work was supported by the US National Science Foundation RAPID Program (1135768),
the Oregon State University Edwards Endowment, and the Japan Science and Technology
Foundation J-RAPID Program.