Tsunami seems to be a virus.

The W32/Zar (also called W32/VBSun.a,etc) worm spreads via email, tempting innocent users into clicking onto its malicious attachment by pretending to be information about how to donate to a tsunami relief effort. However, running the attached file will not only forward the virus to other internet users but can also initiate a denial-of-service attack against a German hacking website. The spreading and total impact at this moment is very low.