# How exactly does an underground nuclear detonation happen?
**URL:** https://boards.straightdope.com/t/how-exactly-does-an-underground-nuclear-detonation-happen/375834
**Category:** Factual Questions
**Created:** [October 9, 2006, 8:40pm UTC](https://boards.straightdope.com/t/how-exactly-does-an-underground-nuclear-detonation-happen/375834 "2006-10-09T20:40:32Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@xanthous](https://boards.straightdope.com/u/xanthous)
#### Post date: [October 9, 2006, 8:40pm UTC](https://boards.straightdope.com/t/how-exactly-does-an-underground-nuclear-detonation-happen/375834/1 "2006-10-09T20:40:32Z")
As simple as “bury it and set it off”? Maybe I’ve been spoon-fed too much irrational fear, or maybe I haven’t fought ignorance hard enough, but a nuclear explosion seems so very gigantic and horrific, I’d think that setting it off underground would still cause massive damage to something somewhere. I remember hearing that the earthquake that created the Indonesian tsunami in Dec 04 knocked the earth off its axis (very slightly, but still…) Would not an underground nuke do the same kind of thing? What about radiation?
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### Author:  [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)
#### Post date: [October 9, 2006, 8:48pm UTC](https://boards.straightdope.com/t/how-exactly-does-an-underground-nuclear-detonation-happen/375834/2 "2006-10-09T20:48:31Z")
A nuke isn’t a moth fart in strength compared to the kind of earthquake that caused the tsunami and that created an effect to the earth as a whole that was so small that the most delicate and sophisticated instruments were needed to detect it. Volcanoes, hurricanes, earthquakes, meteor strikes: almost any violent event in nature is far more powerful than a tiny atomic bomb.
You put a bomb underground primarily to keep radiation from reaching the atmosphere. Doesn’t mean you’d want to vacation there, but that’s about all the far-reaching effect it would have.
The earth is very, very big, and we’re very, very small. Stuff that’s devastating to humans is less than nothing to the planet.
Unless you happen to be under an atomic bomb as it’s going off, you don’t need to worry the tiniest bit about it. Even places that have been hit by bombs, from Hiroshima to the Pacific islands used for hydrogen bomb tests, have recovered their ecosystems and are thriving. I don’t want to minimize the seriousness of the Korean event, but the test itself doesn’t threaten anything.
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### Author:  [@UncleRojelio](https://boards.straightdope.com/u/UncleRojelio)
#### Post date: [October 9, 2006, 8:50pm UTC](https://boards.straightdope.com/t/how-exactly-does-an-underground-nuclear-detonation-happen/375834/3 "2006-10-09T20:50:41Z")
> [@annewaldron](#):
>
> As simple as “bury it and set it off”? Maybe I’ve been spoon-fed too much irrational fear, or maybe I haven’t fought ignorance hard enough, but a nuclear explosion seems so very gigantic and horrific, I’d think that setting it off underground would still cause massive damage to something somewhere. I remember hearing that the earthquake that created the Indonesian tsunami in Dec 04 knocked the earth off its axis (very slightly, but still…) Would not an underground nuke do the same kind of thing? What about radiation?
The USGS has [this](http://earthquake.usgs.gov/learning/faq.php?categoryID=12&faqID=87) to say.
Containing the radiation is part of the reason why it is buried.
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### Author:  [@xanthous](https://boards.straightdope.com/u/xanthous)
#### Post date: [October 9, 2006, 9:15pm UTC](https://boards.straightdope.com/t/how-exactly-does-an-underground-nuclear-detonation-happen/375834/4 "2006-10-09T21:15:11Z")
This was included in the above USGS link: “For example, the magnitude 6.5 earthquake in Afghanistan (5/30/98 at 06:22:28 UTC 37.4 N, 70.0 E) had a source duration of about 5 seconds and an estimated source volume of order 4000 cubic kilometers. This earthquake also had a focal depth of 18 km. The energy release is equivalent to a 2000 kiloton nuclear explosion.”
How many kilotons in your “basic” nuclear/atomic explosion (like Hiroshima, et al)? I’m trying to get my perspective corrected, as I’ve always (wrongly) thought a nuke was WAY worse than a huge earthquake.
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### Author:  [@Smeghead](https://boards.straightdope.com/u/Smeghead)
#### Post date: [October 9, 2006, 9:28pm UTC](https://boards.straightdope.com/t/how-exactly-does-an-underground-nuclear-detonation-happen/375834/5 "2006-10-09T21:28:50Z")
[Here’s](http://www.youtube.com/watch?v=H_oop7VxEx4) a video.
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### Author:  [@Duke\_of\_Rat](https://boards.straightdope.com/u/Duke_of_Rat)
#### Post date: [October 9, 2006, 9:29pm UTC](https://boards.straightdope.com/t/how-exactly-does-an-underground-nuclear-detonation-happen/375834/6 "2006-10-09T21:29:09Z")
> [@annewaldron](#):
>
> This was included in the above USGS link: “For example, the magnitude 6.5 earthquake in Afghanistan (5/30/98 at 06:22:28 UTC 37.4 N, 70.0 E) had a source duration of about 5 seconds and an estimated source volume of order 4000 cubic kilometers. This earthquake also had a focal depth of 18 km. The energy release is equivalent to a 2000 kiloton nuclear explosion.”
>
> How many kilotons in your “basic” nuclear/atomic explosion (like Hiroshima, et al)? I’m trying to get my perspective corrected, as I’ve always (wrongly) thought a nuke was WAY worse than a huge earthquake.
[Little Boy](http://en.wikipedia.org/wiki/Little_Boy) that was dropped on Hiroshima had a yield of about 15 kilotons.
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### Author:  [@MikeS](https://boards.straightdope.com/u/MikeS)
#### Post date: [October 9, 2006, 10:36pm UTC](https://boards.straightdope.com/t/how-exactly-does-an-underground-nuclear-detonation-happen/375834/7 "2006-10-09T22:36:49Z")
> [@Exapno Mapcase](#):
>
> The earth is very, very big, and we’re very, very small. Stuff that’s devastating to humans is less than nothing to the planet.
Or, in the words of the incomparable [How to Destroy the Earth](http://qntm.org/destroy) website:
> [@](#):
>
> The Earth is built to last. It is a 4,550,000,000-year-old, 5,973,600,000,000,000,000,000-tonne ball of _iron_. It has taken more devastating asteroid hits in its lifetime than you’ve had hot dinners, and lo, it still orbits merrily.
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### Author:  [@mks57](https://boards.straightdope.com/u/mks57)
#### Post date: [October 9, 2006, 10:59pm UTC](https://boards.straightdope.com/t/how-exactly-does-an-underground-nuclear-detonation-happen/375834/8 "2006-10-09T22:59:38Z")
The US performed many underground nuclear tests in Nevada. They would drill a deep hole in the Earth, lower the device to the bottom of the hole, and fill the hole with dirt and concrete. The device was connected to control and measurement equipment on the surface with cables. When the device was detonated, it would vaporize the rock and dirt in the immediate vicinity, creating a spherical void, which often collapsed, leaving a dimple on the surface.
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### Author:  [@633squadron](https://boards.straightdope.com/u/633squadron)
#### Post date: [October 10, 2006, 12:02am UTC](https://boards.straightdope.com/t/how-exactly-does-an-underground-nuclear-detonation-happen/375834/9 "2006-10-10T00:02:02Z")
> [@Duke of Rat](#):
>
> [Little Boy](http://en.wikipedia.org/wiki/Little_Boy) that was dropped on Hiroshima had a yield of about 15 kilotons.
That was a pure U235 bomb, very crude and clumsy. The Nagasaki bomb was 22 kilotons, and it too was crude. By the 1950s we managed to put 5 kt bombs into artillery shells. My dad (a career US Army Reserve officer) once told me we even had a nuke **hand grenade**. They discontinued it after they discovered it had a blast radius of 500 yards, but the typical soldier could only throw it 300 yards… :smack:
The first thermonuclear (H) bomb detonated by the US was about 3 megatons (3000 kilotons). As I remember, the Russians detonated a 100 megaton monster but never had anything like that in their arsenal. We sensibly (relatively speaking) settled on a 550-kiloton warhead.
An underground detonation is visible from the surface, but only as an explosion without the mushroom cloud, etc. and substantially less dangerous. My guess is that all that rock moderates the heck out of neutrons and absorbs x-rays.
Interesting note about earthquakes and nukes: by the time the US was ready to test Mike, our first H-bomb shot, Dr. Edward Teller (father of? mother of? the H-bomb) had ditched Los Alamos for his own laboratory in Livermore. He was persona non grata at the Mike test, so he arranged to be be at the seismograph at Cal Berkeley at the time of the test. Someone kindly telephone through to him when the shot went off, and Teller saw it on the seismograph.
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### Author:  [@treis](https://boards.straightdope.com/u/treis)
#### Post date: [October 10, 2006, 12:14am UTC](https://boards.straightdope.com/t/how-exactly-does-an-underground-nuclear-detonation-happen/375834/10 "2006-10-10T00:14:05Z")
> [@633squadron](#):
>
> That was a pure U235 bomb, very crude and clumsy. The Nagasaki bomb was 22 kilotons, and it too was crude. By the 1950s we managed to put 5 kt bombs into artillery shells. My dad (a career US Army Reserve officer) once told me we even had a nuke **hand grenade**. They discontinued it after they discovered it had a blast radius of 500 yards, but the typical soldier could only throw it 300 yards… :smack:
300 yards is a hell of a throw.
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### Author:  [@633squadron](https://boards.straightdope.com/u/633squadron)
#### Post date: [October 10, 2006, 12:53am UTC](https://boards.straightdope.com/t/how-exactly-does-an-underground-nuclear-detonation-happen/375834/11 "2006-10-10T00:53:06Z")
> [@treis](#):
>
> 300 yards is a hell of a throw.
Oh carp. I meant _feet_.
The head guard takes a new prisoner out into the “yard”. As they go through the gate, the new guy hears someone shout out “59!” Everybody else in the yard convulses in laughter. After a few moments, another prisoner shouts out “119!” Again, a round of laughter.
Puzzled, the new guy turns to the guard and asks, “What the hell is going on?”
“Oh!” laughs the guard. “These guys have been in for such a long time they’ve memorized all the jokes. They don’t even have to tell them any more, they just shout out the numbers!”
“No kidding!” says the new guy. “How many numbers are there?”
“Oh, thousands.” replies the guard. “Go ahead, give it a try!”
The new guy waits for the laughter to die down, and then shouts out “42!”
Nothing but silence.
“What happened?” said the new guy.
“Well, ya know,” replies the guard. “Some can tell 'em, and some can’t.”
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### Author:  [@commasense](https://boards.straightdope.com/u/commasense)
#### Post date: [October 10, 2006, 1:12am UTC](https://boards.straightdope.com/t/how-exactly-does-an-underground-nuclear-detonation-happen/375834/12 "2006-10-10T01:12:29Z")
> [@633squadron](#):
>
> My dad (a career US Army Reserve officer) once told me we even had a nuke **hand grenade**. They discontinued it after they discovered it had a blast radius of 500 yards, but the typical soldier could only throw it 300 yards… :smack:
I hate to tell you this, but Dad was either putting you on or misinformed. (On preview, maybe your joke in the previous post is a sign that you were putting _us_ on.)
For the record, the smallest nuclear weapon ever made was the [w-54 Davy Crockett](http://www.brook.edu/FP/PROJECTS/NUCWCOST/davy6.jpg), which weighed 23 kg (50.6 lb). How far can you throw 50 pounds?
Regardless of what anyone thinks of government employees, no one has ever seriously considered actually making a nuclear hand grenade, for all the obvious reasons.
[Here’s](http://nuclearweaponarchive.org/News/DoSuitcaseNukesExist.html) an interesting page about small nuclear weapons that offers some reasons why a man-throwable bomb is physically impossible.
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### Author:  [@T\_SQUARE](https://boards.straightdope.com/u/T_SQUARE)
#### Post date: [October 10, 2006, 3:25am UTC](https://boards.straightdope.com/t/how-exactly-does-an-underground-nuclear-detonation-happen/375834/13 "2006-10-10T03:25:47Z")
> [@633squadron](#):
>
> Oh carp. I meant _feet_.
300 feet is also one hell of a throw. Maybe you’re thinking of a rocket?
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### Author:  [@633squadron](https://boards.straightdope.com/u/633squadron)
#### Post date: [October 10, 2006, 3:47pm UTC](https://boards.straightdope.com/t/how-exactly-does-an-underground-nuclear-detonation-happen/375834/14 "2006-10-10T15:47:12Z")
> [@commasense](#):
>
> I hate to tell you this, but Dad was either putting you on or misinformed. (On preview, maybe your joke in the previous post is a sign that you were putting _us_ on.)
:rolleyes:
Sigh. In my best Foghorn Leghorn voice: “That’s a _joke_, son.”
The worst thing is that _I have told it before in SDMB General Questions_. People didn’t get it that time, either.
end of hijack.
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### Author:  [@commasense](https://boards.straightdope.com/u/commasense)
#### Post date: [October 10, 2006, 3:54pm UTC](https://boards.straightdope.com/t/how-exactly-does-an-underground-nuclear-detonation-happen/375834/15 "2006-10-10T15:54:42Z")
Well, being as you inserted it into a post that, AFAICT, was factual and reasonably accurate, I was concerned that someone else might leave here thinking it wasn’t a joke.
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### Author:  [@633squadron](https://boards.straightdope.com/u/633squadron)
#### Post date: [October 10, 2006, 4:05pm UTC](https://boards.straightdope.com/t/how-exactly-does-an-underground-nuclear-detonation-happen/375834/16 "2006-10-10T16:05:01Z")
> [@633squadron](#):
>
> As I remember, the Russians detonated a 100 megaton monster but never had anything like that in their arsenal. We sensibly (relatively speaking) settled on a 550-kiloton warhead.
The yield was only 50 megatons, though the decision could have yielded 100. A [description of this monster](http://nuclearweaponarchive.org/Russia/TsarBomba.html) is at the highly informative Nuclear Weapons Archive site [http://nuclearweaponarchive.org](http://nuclearweaponarchive.org).
I also need to correct my statement about 550 kt being the standard. I was thinking of weapons in the family of [this warhead](http://nuclearweaponarchive.org/Usa/Weapons/W78.html), the W-78 MIRV warhead for ICBMs, whose maximum yield is 350 Kt. The movie _The Abyss_ prominently features a nuclear warhead whose shape is very similar to the W-78. In my poor memory, the movie also shows someone carrying the thing around, which is clearly impossible since they weigh about 800 lbs.
More modern designs are in use now, though I was unable to find out exactly which warhead equips the Trident. That probably means it’s classified.
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### Author:  [@Jake](https://boards.straightdope.com/u/Jake)
#### Post date: [October 10, 2006, 6:18pm UTC](https://boards.straightdope.com/t/how-exactly-does-an-underground-nuclear-detonation-happen/375834/17 "2006-10-10T18:18:42Z")
I remember throwing grenades in basic training. Them things were HEAVY. Concussion grenades were lighter, but fragmentation grenades were like throwing a ball of solid iron. Don’t remember how far I threw it but by the trajectory it couldn’t have been more than 30 or so feet. (Had to duck, y’know) :eek:
And I was in good shape!
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### Author:  [@bump](https://boards.straightdope.com/u/bump)
#### Post date: [October 10, 2006, 8:31pm UTC](https://boards.straightdope.com/t/how-exactly-does-an-underground-nuclear-detonation-happen/375834/18 "2006-10-10T20:31:06Z")
Tridents carry [W-76](http://nuclearweaponarchive.org/Usa/Weapons/W76.html) warheads of 100 kilotons each.
As for the Nevada Test Site and warhead test dimples/craters, check this link out:
[Nevada Test site from Google Maps](http://maps.google.com/maps?ie=UTF8&z=12&ll=37.043395,-116.002922&spn=0.13181,0.2314&t=h&om=1)
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### Author:  [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)
#### Post date: [October 10, 2006, 8:42pm UTC](https://boards.straightdope.com/t/how-exactly-does-an-underground-nuclear-detonation-happen/375834/19 "2006-10-10T20:42:06Z")
> [@](#):
>
> The movie The Abyss prominently features a nuclear warhead whose shape is very similar to the W-78. In my poor memory, the movie also shows someone carrying the thing around, which is clearly impossible since they weigh about 800 lbs.
I don’t recall anyone carrying the black conical warhead. Cameron seems to be a careful fact-checker type, so I wouldn’t expect that kind of error from him.
On the other hand, you gotta wonder how the SEAL leader apparently managed to get that warhead onto Little Geek and into the water on his lonesome. Saying he used that winch he’s shown playing with doesn’t seem to completely cut it.
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### Author:  [@Duke\_of\_Rat](https://boards.straightdope.com/u/Duke_of_Rat)
#### Post date: [October 10, 2006, 8:50pm UTC](https://boards.straightdope.com/t/how-exactly-does-an-underground-nuclear-detonation-happen/375834/20 "2006-10-10T20:50:34Z")
> [@annewaldron](#):
>
> How many kilotons in your “basic” nuclear/atomic explosion (like Hiroshima, et al)?
> [@Duke of Rat](#):
>
> [Little Boy](http://en.wikipedia.org/wiki/Little_Boy) that was dropped on Hiroshima had a yield of about 15 kilotons.
> [@633squadron](#):
>
> That was a pure U235 bomb, very crude and clumsy. .
Maybe so, but that’s what she asked about.
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