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?
There is a country expected to be submerged in the near future. They are trying to aquire some new space for thier country to exist. I imagine similar if there were enough survivors.