Maybe it's due to increased regulation, once everyone became aware that Italy exports like three times as much as it produces. Maybe there are better tests available for detecting hazelnut oil, which I believe was the main adulterant.

I hadn't heard about any of that. Still, I find it hard to believe that increased testing (if any) would produce a doubling of price.

From what I just read, the situation was bad enough to easily double the price. Not for the testing, but for having to sell actual olive oil. Increased shipping costs are probably contributing as well.

I read earlier in the year that prices would go up. There was some glitch with the weather back in the spring, and it reduced the California olive crop by some serious margin. I can't remember what the specific problem was, and I can't find the article, but I promise that I read it.

If your problem is with foreign oil, well, they're probably just gouging.

Yeah, we generally buy foreign oil. Here in my neck of the woods, it's usually a lot cheaper than the Californian oils.
I read today that Spain is actually sitting on a huge surplus of olive oil from last year's crop, even as they are bringing in a huge crop this year.