What would happen if a nuclear weapon were detonated in deep water?

Suppose a nuclear warhead were lowered to the bottom of the Marianas Trench and detonated… what (aside from the obvious ecological impact) effect would be noticed at the surface?

You’re going to say that a lot depends on the yield of the device, OK; pick any figure you like for yield (or more than one, if you like).

I guess the question is whether or not the hot vapor makes it to the surface, or get absorbed on the trip. I myself have no idea.

I don’t want this to happen, but I’d still sure like to see it, if it did happen!

Some would speculate that there would be massive volcano eruptions, tidal waves, and earthquakes. I would say that’s BS, and that even with a very large-yield nuke there wouldn’t be much to see on the surface. If you really detonated it at the bottom of the Marianas Trench (36,198 feet deep) the disturbance would surely dissipate by the time any energy reached the surface.

A slight hijack:

If you dropped a nuclear weapon off of a boat into the trench, would the water pressure be enough to compress the sphere of fissionable material together and cause a chain reaction? IIRC, this is done with high explosives in a real bomb, would the weight of 36,000 feet of water do the job?


There is a picture of a nuke going off in water on the left side of this page:

Rest of the page has some cool things that happen when you use a nuke.

Another site with underwater test info, shallow water:

As far as I know, the military only tested nukes in shallow water.

As far as the nukes being compressed by pressures of the deep, it hasn’t set off any of the nuke bombs currently sitting on the ocean bottom. The US and Russia have both lost bombs which are still on the bottom in various places around the globe. I know there are some which were lost in water over 10,000 feet deep.

handy and Harald Bluetooth seem to have covered the detonations in shallow water. However, the alleged deep-water test is the supposed South African/Isreali explosion. In practice, apparently barely noticed by either East or west.

The U.S. tested an underwater explosion as part of Operation Crossroads. The first detonation was a plane-delivered bomb that detonated above the surface, designated Able. The underwater test was the second shot, designated Baker. Baker was detonated at a depth of about 90 feet, and it was a much more impressive explosion than Able. The damage it caused to the test ships on the surface was catastrophic. Battleships were literally tossed into the air by the explosion. This page from the Department of Energy has films of the tests, plus some stats: “Two million tons of water were contained in the eruption and two million yards of sediment were removed from the lagoon floor. Nine [test] ships were sunk.”

A planned third, deep-water test, Charlie, was never performed. I reckon they either feared the result, or they just plain ran out of ships to sink after Baker. Baker was, by the way, a 21-kiloton device, the size of the Nagasaki explosion. We have much bigger stuff now.

No. Theres more to causing an explosion than merely compressing the core to supercriticality. It must be done very quickly, and in practice, high explosives are used to do this, as you pointed out.

Max Torque got part of it. However, the scrapped Charlie shot from Crossroads was later done. Not as deep as 36,000 feet, of course, but I believe at about 1000 feet or so. They set up some old submarines, put cameras in them, and detonated a test. I believe the device was suspened from a barge, similar to the Baker shot at Crossroads. You can hear the creaking and such on the audio of the tape, and then the water rushes in and takes out the cameras and, of course, the ship. Of course, it depends on whether you call 1000 feet deep water–seems plenty deep enough for me. So, in theory, we could use nuclear depth charges without affecting the surface ships if the enemy sub was deep enough.

According to this compilation of all the nuclear tests performed in the Pacific Ocean (PDF), the deepest underwater detonation was 600 feet below the surface:

Operation Wigwam, May 14, 1955

I’ve seen video of the French tests that they did under the sea floor. It was done off the coast of a tropical island in the South Pacific. Amazingly clear blue water, and then WHUMP there was an image for a second that looked a lot like a giant version of the “droplet” shot of milk that was made with high speed photography.

I take it that marine life, especially hearing dependant mammals such as whales, don’t really cope too well with submersed nuclear tests, yes? Are we safe in assuming that whales and dolhpins had ringing ears for absolute yonks thereafter?

According to Glasstone and Dolan (Effects of nuclear weapons 1977).
The Wigwam test at 2000ft produced a gas bubble which as it rose to the surface expanded upto a point where it was below ambient water pressure, then contracted again, doing this 3 times before bursting through the surface at 200mph.
They say that after 3 cycles of expansion and contraction enough steam will have condensed out to make any more pulsations unlikely.
The plume produced when the bubble reaches the surface seem to depend on whether the bubble was expanding or contracting on breakthrough.
Though in all cases a nasty radioactive “base surge” (expanding rolling mist cloud) is produced.
The following pdf file contains details on the test, mostly about how it was carried out and the cleanup/monitoring of ships afterwards http://www.dtra.mil/td/pubs/t8579.pdf

How about this? (even has a picture!)


Are we safe in assuming that whales and dolhpins had ringing ears for absolute yonks thereafter?

This is why people were refusing to buy French wine while that was going on…

Now, did the boycott work, or did people get bored with it and the French are still doing that?

Boo Boo Foo wrote:

In this U.S. Army Corps of Engineers document, you can find equations for estimating the amount of fish an explosion will kill in this section. Per Young’s equation, the safety zone range for, say, 10-pound fish with swim bladders around the Wigwam explosion would have been about 107,000 feet. Per Hill’s model (and the example fish used on the cited page), 50% of the Pacific herring 118,500 feet (over 22 miles) from the explosion would have been killed (a higher percentage closer, fewer farther).

The document also states that marine life without gas-filled organs (like swim bladders) tolerate explosions fairly well. Plants, on the other hand, can have their structural parts crushed by the shock waves, and most of them quit photosythesizing for a while, at least.

Unfortunately, the section on marine mammals appears to be missing a table, so I can’t follow Hill’s model for them, and the equations listed from Young all assume a 200-foot blast depth (however, had the Wigwam explosion gone off at 200 feet, then according to Young, 20-foot whales more than 49,250 feet away would have had no injuries, and adult porpoises 65,370 feet away would be unharmed, as well).

The next section on marine mammals, says in part: