Trees and hills versus sea walls.
Going green in tsunami thinking means engineering a series of hills to slow down a tsunami wave and also planting those hills with trees. It may take decades before the trees are mature enough to make a serious difference, but at the rate that governments are not reacting to the tsunami threat -- it might be much faster than building a sea wall.
See this article, Rethinking tsunami defense.
I do have to point out that there will be those people who object to having their ocean views obstructed by hills and eventually trees. Which shows that you can't make everyone happy all of the time. Just, maybe at the time of the tsunami ...
It was shared by Professor David Hill.