The Japan quake and resulting tsunami was a bit of a wake-up call for modern society. Japan had engineered tsunami barriers for what they believed to be the maximum credible event. These were broken and tossed aside like toys.
This does not mean that we can or should do nothing. See 'Tsunami-Resistant' Port To Be Built In Crescent City This is not a major shipping port, but a commercial and recreational fishing port. As the story notes, the design measures being put in place will not counter the largest possible tsunami that can be generated, but they will reduce the damages from smaller events that have had a fairly regular occurrence and impact on that coastal town and port.
I equate these types of actions to wearing your seat belt in your car. You know that you might be seriously injured or even killed with your seat belt fastened, but the chances of that go way down because of the mitigating nature of the belt and its ability to restrain you and keep you safely within the confines of your car.
We need more "seat belt like" measures to improve our mitigation efforts across a wide variety of hazards here in the United States.