It's clear the Med region has experienced a great many flood-like events, from tsunamis caused by volcanic eruptions (Santorini) to prehistoric "global warming" when the Pleistocene ice sheets melted and raised sea levels. Untangling the very complex past from current-day geological clues is a difficult and very long-term project.
“Based on” an Assyrian epic I’m not sure of. I’ve done a little textual analysis in my day and you can usually tell when one text is based on another because it preserves certain idiosyncracies of the original. Like, you make a mistake and then I just copy the mistake.
There are obvious similarities between the two stories, but to my eye it looks more like they were both independent traditions that preserve an original, probably oral account of the event. And believing as I do in the infallibility of the Sacred Word, I know which account is correct. :)
But yeah, trying to attach this all to geological events is hugely difficult. I wish people would just keep their powder dry and not rush off to adopt wildly speculative theories to prove or disprove the Bible. Let’s make sure we have our exegesis right, and let’s make sure we have our geology right, and the rest will follow.