Quote:
Originally Posted by zelda_pinwheel
 does 20cm count as a tsunami ? don't you have bigger waves than that when the water is dead calm ? |
Tsunami's strength includes wavelength as well as amplitude:
http://en.wikipedia.org/wiki/Tsunami#Characteristics
It's a large body of water being shifted, compared to, let's say, a surface wind-wave. So, let's say the waves that come in are 2m, well, that water stays at that height for a long time and keeps coming. 2m normal waves are relatively common here, but a 2m tsunami would likely inundate Hastings Street (behind Main Beach).
Saying all this, yes, it's looking small (but impressive, considering the distance it has travelled, and the speed it did it in).