Why don't we use nukes to save Japan?

Now that I have your attention, I would like to propose a method of preventing a good deal of damage from tsunami waves. It's called phase cancellation.

Phase what?

The phase of a wave refers to the direction its traveling in. The top illustration shows two waves that are traveling in opposite directions. The bottom shows the two waves traveling in the same direction.

For you mathy people, two waves traveling in opposite directions with the same amplitude and frequency are shifted 180 degrees or pi radians away from each other.

How does it work?

When the ups of one wave line up with the ups of another wave, resonance occurs (bottom picture), which means the resulting wave is twice as large as the two other waves. When the downs of one wave combine with the ups one one wave, they cancel each other out and the wave no longer exists (top picture).

This is the same technology used by Bose in their noise-canceling headphones.

So what about Japan?

In the case of the Tsunami in Japan, given enough advance warning, we could use explosives to set off waves of the same frequency of the tidal wave but headed straight at the epicenter to hopefully cancel out the wave. This may sound reckless and destructive, but it takes massive amounts of energy to stop a massive tidal wave. Nuclear bombs probably would be a bad idea to use because of radioactive fallout (unless we're all itching for nuclear disarmament), so we would probably use more conventional explosives.

Science nerds, read on. Non-Science nerds, read at your own risk.

According to the Law of Entropy, the bombs we set off would have to release more energy than the wave we're stopping, which would result in creating another tidal wave, which could be larger or smaller, depending on the effectiveness of the charges. We would have to find a way to direct all the energy from the blast within 180 degrees (a half circle) instead of in a full circle to do so safely, just like Bose can use a speaker to direct sound energy in only one direction in their noise-canceling headphones.

Since we presumably can't detonate a bomb on top of the epicenter as the earthquake is occurring, the best strategy would be to detonate the charges in near any landmasses that lay in the path of the tsunami. By doing so, we eliminate the possibility of completely cancelling out the wave. However, we would be able to coordinate the charges to create an 'envelope of safety' around a landmass by aligning the nodes of the wave around the landmass in question. Take a gander at the highly technical drawing below.