Not one big enough to cause another great extinction, but small enough to just turn a whole small country and parts of neighboring ones into a huge crater. Will the people who was evacuated out after NASA stated a warning try to rebuild the country after everything has settled down or do they’d become citizens of another country?

Edit: after reading the comments, maybe turning a small country into a crater is too much, what about just level the place, or in any way that make it uninhabitable for a period of time?