Fukishima style perhaps. Send one out in a trawler via a proxy. Detonate near Los Angles.
Think outside the box.
The US is moving an advanced missile system to the Pacific island of Guam as a precaution following threats by North Korea, the Pentagon has said.
Really? Only if they are already ashore; can't lob one from there to either of the US coasts.
Sell all your stocks! Run and hide folks from the fallout and incendiary blast wave that is imminent.