[crz]

Campi Flegrei. This is the one to watch.

Yellowstone? Nope. Unless there comes a earthquake over 7 in that basin. That might unzip the thing.

[hinckley buzzard]

I visited Campi Flegrei last Spring. Lots of steam, the earth was hot to the touch, but not much seismic activity currently. Still, you are right, with Vesuvius considered still active, the area is active recently enough. I don't know if the earthquakes in central Italy are related though. Do you?