Re:false warnings (Score 1)

Earthquake magnitude and orientation are the controlling factors in tsunami generation. It's not the vibrations, high frequency or otherwise, that cause the tsumani. It's the sudden displacement of mass in water (well, ok, you could argue that's a very low, 1-wavelength frequency signal, but that's getting away from the main point...).

Large enough earthquakes that have sufficent energy release to displace large quantities of mass will have very broad-spectrum vibrations anyway. High frequency earthquakes, will, by their nature, be small. And hence of very little tsunami-generating potential.