I had the chance to discuss the North Korean bomb test with a senior scholar who studies “bombs” for a living. He reports the following as the current consensus among international-security types:
1. The test was almost certainly a fizzle.
2. The North Koreans were probably trying to test a deliverable warhead (i.e., something small enough to be a warhead on the cruise missiles they have) rather than a mere test device. That increased the risk of a fizzle.
3. The intended yield was about 4 kilotons. That’s about a quarter the size of the Hiroshima bomb. Since the area of destruction grows as the square root of the yield, that means it would destroy about half the area that the Hiroshima bomb took out.
4. The obvious target for such a warhead would be an aircraft carrier. If North Korea were known to have nuclear-tipped cruise missiles, our carriers — which in the past have been used to threaten North Korea — would have to keep their distance.
5. Unlike a nuclear attack on a city (by North Korea or by a terrorist group to which North Korea had supplied a nuclear weapon), which would be national suicide, an attack on a purely military target such as a carrier would look more like an ordinary act of war than it would like an act of mass murder, especially since an attack over water minimizes radioactive fallout. The North Korean government could then reasonably hope to escape massive retaliation.
6. The tactical purpose of the test was to force the U.S. back to the bargaining table. The strategic objective is a security treaty under which the U.S. promises not to invade.
7. From that perspective, the test was probably a mistake; net-net, the North Korean bargaining position just got worse rather than better.
What is so bad about promising not to invade again? It seems like their conventional forces are destructive enough so that you would not want to invade and lay waste to Seoul.
“Since the area of destruction grows as the square root of the yield, that means it would destroy about half the area that the Hiroshima bomb took out.”
Is that a fact? My rough calculations suggest that the area should grow as the (2/3) power, if you model this as the area of an equatorial cross section of a sphere with volume proportional to the yield. Maybe that’s not the right model, and in either case it’s not a huge point…
Alex F
I seem to remember from Kosta Tspsis’s book that you are right.
See also the Arms Control Wonk blog
http://www.armscontrolwonk.com
which had the best line of the whole affair:
“I close this discourse about operational confidence by noting that the United States has built a missile defense that does not work, to defend against a North Korean missile that does not work, that would carry a nuclear warhead that does not work.”
http://www.armscontrolwonk.com/1233/so-like-why-didnt-it-work
Would a nuclear strike on water not generate a tsunami?
there have been more powerful bombs tested over water (e.g. bikini atoll), none generated tsunamis.
Tsunami generation requires an elevation of the entire water column as happens with a tectonic plate shift near the ocean bottom or a massive landslide into the ocean as predicted in the Atlantic and as witnessed on a local scale at Lituya Bay, Alaska.
http://www.prh.noaa.gov/ptwc/abouttsunamis.htm
> there have been more powerful bombs
> tested over water (e.g. bikini atoll),
> none generated tsunamis.
Some pretty good-sized waves, though. The British tested their first atomic bomb underwater in a harbour (in Australia, natch!) specifically to see how much damage would be done in such a scenario.
Cranky
Brock
As others have pointed out, you would need a *big* bomb to create a tsunami like wave. A tsunami has the kinetic energy of several hundred hydrogen bombs, AFAIK.
Martin Caidin had a scenario where the Russians deployed 100 megatonne bombs wrapped in sodium-lithium blankets on freighters.
3 bombs, 1 off each US coast.
The result would be a level of radioactivity (for a few weeks) which would have killed everyone in the coastal regions of the USA.
As I understand it, the Soviets were hell bent on testing a 100 megatonne bomb at Kamchatka. Kruschev ordered it ‘dialed down’ to 50MGT because he was worried about damage to the planet (all the way to disrupting the tilt of the earth on its axis). Don’t know whether that is Kruschevian disinformation *but* I believe it is documented that the Russians ‘turned down the volume’ on their biggest test.
Fortunately a hydrogen bomb is a step beyond the kind of atomics Kim Il Sung II is mucking with. The Israelis may have one, the Indians too, but its unlikely the other emergent nuclear states do.
If you wanted to do real havoc, a burst of a bomb in low orbit over the US would do far more damage: take out power transmission for hundreds of miles, as well as radios and other electronic devices.