US President Donald Trump warned on Tuesday that "all options" are again on the table after Pyongyang tested a ballistic missile, this time a rare firing of a projectile over Japan.

The new missile test has triggered consternation on the ground, causing sirens to blare in Japanese towns, stocks to dip on Wall Street, and diplomats from Seoul and Beijing to Moscow to call for either further sanctions or more restraints.

But what can the average citizen do under the apocalyptic threat of a missile or nuclear war? Among a myriad of answers, the headline of a news story caught my attention: "Bomb shelter business booms as Trump and North Korea posture".