In message , griz
writes
reading your reply, I was hoping you would actually explain what the
difference is ...

In my dictionary
tidal wave:
1. a nontechnical name for tsunami
2. an unusually large incoming wave, often caused by high winds and
spring tides

tsunami
a huge destructive wave, esp one caused by an earthquake. Also called:
tidal wave.

Does this mean that in the common use they are synonymous, but only
tsunami is really caused by earthquakes?

Following this discussion, I though I would surf around a few European
newspapers to see what they have done: Le Monde, which I would have
expected to use a French word, seems to use tsunami; Der Spiegel seems
to refer to Flut - flood; in Spanish papers I saw 'maremoto' which is, I
think, tidal wave; Corriere della Sera has tsunami; and Hungarians use a
word that roughly translates as 'leaping flood'.

--
Klara, Gatwick basin