Tsunomo

So, I was thinking... say I was a terrorist bent on striking down the infidels, how would I do it?

I'd have the resources to be able to wreak some decent havoc but can't actually engage American soil with said resources since the twin towers came down and everything went all pre-marshal law and stuff

What would I do? hmmm

I think that I would find an unprotected off shore cliff face or three that 'could' be havoc-ed with my resources and let the converging waves of the mega-tsunami I had created inundate about six miles of coastline to see just what kind of pressure that volume of water pushing and then pulling on the San Andreas fault-line would do and the destruction it could wreak.

I think we can all agree that this would be a bad thing, yes?

So, what to do? Can't protect every single cliff face in the south pacific from shenanigans but we might be able to disperse the effect of a tsunami altogether given a large enough budget.

Rows of perforated pipe stretching thousands of miles would parallel the coastline of [place-country-name-here]. Each section of pipe is equipped with enough compressed gas to equal the duration of the longest wavelength of tsunami yet recorded and when a tidal wave is detected, the system fills the water with bubbles before the wave reaches shore.
The physics of the wave amplification due to the elevation of the sea-bed would change entirely and the tsunami should... fizzle, (technical term, it will be on the test), and dissipate.
That's the way I see it going down in my head anyway. It should be pretty easy to test.

Crisis averted.