Blogs from the Coastal Structures Team - Tohoku, Japan Earthquake and Tsunami of 2011 - page 76

overtopping the 15-meter-high structure and sending water to the area upstream. The
photo shows easily seen water level marks on the gate towers (as marked with red
arrows). The considerable power of the water cascading over the gates is evidenced
by the scour holes and failed roadway bridge in the lee of the structure.
Dr. Shigeo Takahashi, director of PARI, Japan's Port and Airport Research Institute,
has been guiding and interpreting our visit to the tsunami-affected area. The PARI
team are our Japanese hosts on this survey and Takahashi planned the itinerary for
our survey together with Lesley Ewing, Ron Noble and Jim Marino. He has drawn on
his extensive experience with both tsunamis and port development in Japan to give us
valuable information on Japanese coastal construction and practices as well as data
from both the latest tsunami and historical disasters.
One kilometer down the coast, the houses of the fishing village of Otanabe remained
safe behind a 15-meter tsunami barrier. The tsunami height was 12.5 metetrs at the
barrier, most likely because of the orientation of the coastline and the presence of
coastal protection in the fishing harbor. Both here and at the Fudai River, the walls
were founded in bedrock and no flanking or end erosion was observed.
We continued southward down the Tanohata coast, passing the Hotel Raga which
experienced a runup of 22 meters. Arriving at the port of Omoto, we observed
reconstruction activities under way and new tetrapods staged for placement on the
seaward side of the breakwater. The hillside to the north of the harbor showed a
consistent damage line of around 20 meters.
Figure A.4 Amid tsunami damage all over Taro Bay were markers on a stone face
that recorded the heights of previous tsunamis in 1896 (top arrow) and 1933 (bottom
arrow). (Source: Catherine Petroff)