I was just having a look at the Memory Alpha entry for Vulcanis Lunar Colony and it says it's not clear where this colony is located. I'm thinking that 'Lunar' only pertains to Earth's moon, as much as a Martian colony could only be located on Mars. So is it possible that Tuvok was born in our neighbourhood?
I dunno, for some reason the addition of the word 'Vulcanis', rather than 'Vulcan' would make me think otherwise, so it could be an odd translation issue. Unless there's a specific location on Lunar that's called Vulcanis?