Nukes and Quakes

Someone posed this question to me today: What is the likelihood of detonation of nuclear weapons in silos in an area hit by an earthquake? The person didn’t specify the level on the Richter Scale. I am no physicist, but even with my rudimentary understanding of how nukes detonate and how missile silos are constructed, I felt pretty safe in saying, “Marginal at most.” Now I’m questioning my answer.

I can find plenty on the Internet about whether or not the detonation of nukes can cause earthquakes, but nothing on whether earthquakes can cause nuclear detonation. I also searched the SD archives with no luck. This leads me to assume that either a) this is such an incredibly stupid question that nobody has ever deigned to answer it or b) I have a great idea for a mindless action movie.

Was I right or wrong in my answer?

Please have patience with my lack of intelligence in this area. I like to think I make up for it with my spectacular looks. :cool:

Nuclear bombs are extremely precise, and it’s quite a difficult engineering process to get them to trigger. I think it’s safe to say that the shock of an earthquake, or even a big fire resulting from the quake, would be extremely unlikely to set one off. They are designed to survive plane crashes without triggering, so something like an earthquake wouldn’t stand a chance of setting one off.

Nuclear bombs are not like conventional bombs. You could stand there and pound on it with a sledgehammer and it won’t go off.

In 1966 a B-52 crashed in Spain that had four hydrogen bombs on board. None of them detonated.

ETA: Nuclear silos are also built to withstand nuclear attack. I doubt an earthquake will bother them overly much.

I don’t have a cite handy, but I recall reading somewhere that missiles armed with nuclear warhead cannot detonate unless an accelerometer confirms the missile has been moving at a speed consistent with its intended operating speeds in the thousands of miles an hour. Earthquakes wouldn’t do anything to that.

Not sure how gravity bombs with a nuclear payload are kept safe, but as Whack-a-Mole mentioned, plane crashes haven’t set them off in the past.

http://en.wikipedia.org/wiki/Nuclear_weapon_design#Warhead_design_safety

Hope this helps a little.

They have tested the safety/arming systems, and other things like setting them (the weapons) on fire or crashing the plane they are on into the ground.

I imagine the folks actually working on these things on a day to day basis don’t want them going off in their face.

See also: http://en.wikipedia.org/wiki/Nuclear_weapon_accident#Broken_Arrow for terminology.

I should note that in the case of the accident in Spain two of the four bombs had their conventional explosives detonate. This did not result in a nuclear detonation but did make them the first dirty bombs and contaminated the area.

Nil.

For the reason that has been stated, but also because silos are designed to handle extreme loads.

Pretty much what everyone has said. As far as I know, the nuclear weapons aren’t even armed when they are sitting in their silos, so it would be impossible to trigger them unless someone armed them first.

My guess is that a massive earthquake would basically render them completely inoperative, and if the silo collapsed could destroy them or set off the rocket at most. None of which would cause the bomb to go off (it could and would set off the conventional explosives though).

-XT

For your first point, I’d be delighted if I could find my book with the cite—it’s a Greenpeace publication on nuclear power. Obviously biased, but they claimed that during a riot aboard a U.S. Navy ship during the late 1970s, disgruntled crew entered a magazine containing special weapons.(!) Said crew proceeded to beat on the weapon(s) with a hammer, denting the weapon but causing no other harm. I was surprised reading the account that the Marine detail guarding the magazine didn’t kill the rioters. Again, it sounds incredible to recount, and I really need to find the book. I do know that Trident SLBMs have been dropped by accident during loading, and the impact loads were obviously insufficient to detonate the high explosives within the warhead (despite concerns over said HE sensitivity in the W-76 warhead initially within the Trident C-4).

For the second point, here’s a link concerning an accident in 1961 with a SAC B-52:

I don’t know but I imagine that current warhead/device designs are much more robust. In a memorable accident, a Titan II ICBM leaked its fuel, which then later exploded within the silo. The explosion threw the 740 ton silo cap of concrete and steel to one side, and the 9 MT RV was thrown 600 feet through the air.

Compared to those traumas, and especially since the U.S. doesn’t deploy liquid fueled ICBMs anymore, I wouldn’t worry about an earthquake setting weapons off. Now, in earthquake country, e.g. LLNL, I would make sure any pits or cores or other fissionable material, were stored in earthquake-resistant cradles, to prevent any inadvertent criticality accidents.

An IND (Inadvertent Nuclear Detonation) is extremely unlikely. Full scale designs can be easily tested in the most severe and drastic ways imaginable by simply replacing the nuclear materials with lead. You can then bake, freeze, shake, drop, immerse, vibrate or anything else you want to do to see how effective the safeguards are in a full scale design.

We are aware of some interesting accidents that have befallen Soviet weapons, and I recall a Chinese fighter jet landed with a live nuke (a big 'un) after the shackle release failed to , er, release. The bomb only had a few inches clearance between it and the runway when it landed. (this was an extremely serious ‘event’ and fortunately, the bomb was successfully safed)

I once read somewhere that US atomic weapons use a very clever safety mechanism - each one requires a unique code to arm it, and that code actually contains timing information for the detonators. Each bomb is machined slightly differently, and so the explosion wavefronts need to be precisely aligned by slight offsets in the detonator timing, in order to get the bomb to explode, and not just fizzle. I just did a Google search, and I couldn’t find any references, but I’m sure I’ve heard this somewhere. It would certainly make a lot of sense, even if it’s just a rumor.

Do you have a reference for this? I have never heard of that before.

I think I’m right in saying the silos are designed to survive (realatively) near-misses from nuclear weapons.

Yes.

A direct hit will annihilate them of course but a near hit won’t (say a couple miles away).

That is why our silos are spread out. Even if a nuke got a direct hit on one the next is too far away (couple of miles) that it will survive. This makes your enemy have to target every silo individually which is difficult and expensive.

Quite surprisingly, there have been many events where nuclear weapons have been accidentally subjected to extreme abuse such as an airplane crash.

Here is a list of a few dozen (:eek:) “broken arrow” events. In some of them, the high explosive of the bomb detonated, but no nuclear explosion resulted.

List of Broken Arrow events

As always, I’m a wiser, better-informed person because of the teeming millions. Thanks!

I think a nuclear missile silo can take a nuke hit WAY closer than a couple of miles. It wouldnt suprise me if that number was more like hundreds of yards. Just a gut feel and vague memories though. Now, thats for your typical 100 kiloton ICBM bomb, not those 20 megaton hydrogen monsters.

Why can’t it be both? Surely you’ve seen some of the retarded drivel Hollywood has used as movie premises?

Oh, I was banking on it being stupid enough to draw that highly coveted 12-15-year old audience.:slight_smile: I just figured if it was so incredibly stupid that even some sugar-hyped 12-year-old would be yelling, “Aw, THAT couldn’t happen!” through a mouthful of Skittles, I might have trouble getting it past the suits at Paramount…Wait. What am I saying? Those are the suits at Paramount!

I stand corrected. Thanks.

It’s likely enough that they created an acronym for it.

:cool: