at least some of which would happen aboveground No reason to think this is true, All the major powers (US, Russia, China) have extensive underground testing ca

at least some of which would happen aboveground No reason to think this is true, All the major powers (US, Russia, China) have extensive underground testing capacity. All the recent powers have only done underground testing (Pakistan, India, North Korea). China was the last country to do an above ground test, in 1980, the 22 tests they've done since then were all underground.