Here is a link for a list of the world's worst natural disasters
'Natural Disasters' [the famine in nothern China in 1969-71 is called a natural disaster, this is something of a misnomer]
Also the current death toll from the recent tsunami may come close to the 1730 toll (137,000) for an earthquake in Japan, putting it near the top 10 in world disasters.
Here is a link for Pompeii (many also died at Herculaneum) with refernces and other links
Pompeii. No figure is given for the number of deaths but I think it was in the ten's of thousands. Hard to know exactly anyway.
-Zeno