I try not to think about that.
If I had a time machine, I'd go back the night before the eruption and steal the scrolls, digitally scan all of them, then return them ten minutes after stealing them. It wouldn't matter how long it took to get the scanning done, as long as I set up the scanning lab in a different time and place prior to their rediscovery. :^)
I've got some other great plans regarding the use of technology that doesn't exist (AFAIK) and using money I don't have. :^)
I’d go back 2 nights before and tell them to get the hell outta Dodge.