I’M EXPECTING AN EARTH-SHATTERING KABOOM: U.S. Upgrades Its Biggest Non-Nuclear Bomb.

A fourth upgrade to the Boeing Co. bomb, the GBU-57, has been completed and the existing inventory is being retrofitted, Captain Emily Grabowski, an Air Force spokeswoman, said in an email. The modification “has improved the performance against hard and deeply buried targets,” she said.

Bombs known as bunker-busters have been in the Air Force’s arsenal for years for potential attacks against buried targets. The GBU-57, which is six times bigger than the 5,000-pound bomb the Air Force has had for years, could be used if the U.S. decided to hit underground nuclear or missile facilities in North Korea, as tensions persist over Kim Jong Un’s growing nuclear arsenal.

Three B-2 bombers were deployed to Guam this month in what the Air Force said was a planned rotation. Grabowski declined to say whether the GBU-57 also been sent to the Pacific region.

Bigger, please.