If there is a device, and NEST can't findit, and it goes off, then what? 8 miles offshore and surface detonated? Unless it's a really big device, you get a big flash, followed by lots of steam, and some radioactive, vaporized fish, ship parts and cargo parts blowing farther out to sea. Unless the wind shifts. A quick look at the current winds shows it blowing off shore in that area.
I would recommend not looking in that direction the moment it goes off, though.
Oh, and by the way, 8 mi out is still within US territory, and we would probably lose several ships and several hundred guys. Which means that it will be time to turn the perp's turf into a hot, glowing parking lot.
Test: Umbrella
Time: 23:15 8 June 1958 (GMT)
11:15 9 June 1958 (local)
Location: Enewetak lagoon
Test Height and Type: Underwater, -150 feet
Yield: 8 kt
Umbrella was a DOD sponsored weapons effects test for a
medium depth underwater explosion. A Mk-7 bomb was used for
the test (30 inches in diameter, 54 inches long, device weight 825 lb.)
in a heavy pressure vessel (total weight 7000 lb.). Very similar to the Wahoo device.
The device was
detonated on the lagoon bottom NNE of Mut (Henry) Island.
An underwater crater 3000 feet across and 20 feet deep was produced.
