Comment by southernplaces7 | Hacker News Reader

Comment by southernplaces7 | Hacker News Reader

Parent Full thread

southernplaces7

Basically neither really. the energy unleashed by even moderate earthquakes through natural tectonic tension release is proportional to the degree of accumulated tension getting released, and in all such cases, these tensions contain a potential energy that is far, far greater than what any normal nuke generates. In other words, a nuke placed in the San Andreas fault even with extreme care to have maximum impact, would probably do almost nothing against the much bigger energy, and resistance to its release, already going on.

A key thing is that with nukes or any large artificial blast, the energy is pretty much released in a compact area right out into the open. With earthquakes, energy is spread across large areas and often starts far underground, yet still causes damage over a very extensive area. This is part of why earthquakes are much more energetic then man-made blasts.

Large explosions (especially nukes) do produce earthquakes and minor seismic movement, but it just doesn't compare to the comparative megaton-equivalent forces that natural tectonic movements create underground during really notable earthquakes, just like the one being "predicted" in the article above.

The energy released by an earthquake of magnitude 8.0 on SA is approximately 6.31×10^16 joules. When converted to an equivalent in terms of TNT, this energy amounts to about 15,080 kilotons of TNT. (About the same as the Castle Bravo nuclear test)

Now, to use such a weapon to cause a stress-relief earthquake, some factors need to come into play: Depth at which the device should be detonated to optimize stress relief without causing surface damage. detailed seismic imaging and rock mechanics studies. Geometry of the fault zone.

Even w/ a Castle Bravo type test, massive radioactive fallout would occur in groundwater as well as air. There's also the chance that such an event would cause local volcanic activity.

>this energy amounts to about 15,080 kilotons of TNT. (About the same as the Castle Bravo nuclear test)

I thought of mentioning Castle Bravo or Tsar Bomba as contray examples of my general argument, but I simply stated "normal nuke". Neither Bravo or Tsar were at all normal nukes and especially by modern design standards that focus more on the multi-kiloton range and precision-guided multiple strikes against a given area target.

Even with those insanely giant old bombs, I wouldn't absolutely be sure that they'd achieve a massive tension release, even in a fault as tense as the San Andreas. Such a thing is likely just a bit too variable-prone to model effectively.

As for something like a Hiroshima type bomb doing it, bloody unlikely. The original post comment simply mentioned a bomb so I didn't want to stray into the biggest mega explosives of human military history.

Reply on news.ycombinator.com