A Consideration Aimed at Improving the Resiliency of Protective Structures Against Tsunami - Post-Tsunami Hazard: Reconstruction and Restoration - page 212

isestimatedtobelessthan0.1undereverytsunamiconditionbycomparingcases5
and 2. The effect of breakwaters in the shallow region also decreases as the tsunami
height increases and it estimated to be 0.1-0.2 by comparing cases 6 and 2.
Therefore, the influence of both the protective effect of breakwaters in the deep
region and the crown height of breakwaters becomes larger as the tsunami height
becomes higher.

14.4.2 Effect of Countermeasures

Figure 14.11 shows that the effect of the different countermeasures. The crown
height is the same as the original height, but a hard countermeasure against sliding
is designed in each case. Countermeasure A in the figure is that all breakwaters
including submerged breakwaters can withstand twice the height of the 2011 tsu-
nami. Countermeasure B is that only breakwaters not including submerged break-
waterscanwithstand1.5timestheheightofthetsunami.CountermeasureCisthat
breakwatersinthedeepregioncanwithstand1.5timestheheightofthetsunami.
The protective effect of each countermeasure can be estimated by comparison with
theoriginalcase.CountermeasureCseemstobebetterunderlessthan1.5timesthe
height of the tsunami. Even so, in the case of twice the height of the tsunami, all
countermeasure except Countermeasure A would be useless. From this point on,

Fig. 14.11 Protective effect of countermeasures