Ok, let me get a few things straight.
1: I don't think moving out of the calamity's range would change your memory back to normal. If it were that easy, the mystery would've been solved LONG ago.
2: Supposing that to be true, that still wouldn't fix Reiko and that other guy's memories about 15 years ago, since
that particular memory alteration was caused by
graduation (IE, the muddled memories are due to their memories being 'reset').
3: Ok, all the theories about the calamity's range can be thrown right out the window. Either the calamity's range moves around like other people suggested, or... well I dunno. At least I like how the mystery isn't over yet.
4: Unless confirmed otherwise, I'm going to stick with Librarian Guy's explanation that these deaths don't happen on purpose.
5: Hot Countermeasures girl is hot.
6: