5 ms·

I'm curious, how viable would a controlled underground atomic blast be in this scenario?

eponeponepon 9y ago
You might be underestimating the size of even a small tectonic plate. Large explosions will cause seismic waves, of course, but to actually move anything, I believe you'd need a spectacularly big one - bigger by far than anything we've detonated before.
sandworm101 9y ago
My understanding is that the thousands of tiny detectable tremors each day worldwide involve as much energy as several atomic bombs exploding every day. The energy to move hundreds of cubic miles of rock even a nanometer is difficult to imagine.
- EwanG 9y ago
  Which suggests finding a place with constant tremors might be worthwhile to try to harvest energy from? Possibly just by having a material that generates a current when flexed?
  - dmix 9y ago
    It's nearly impossible to predict earthquakes so I don't see how this could be feasible at all. Scientists have been trying hard for decades with no luck. It's been one of the most impenetrable natural phenomenons. At most you get decade+ long likelihoods of the number of earthquakes of x strength, across a very large geographic area. Even in places with a high number of them it's very challenging to give probabilities of when, where, or how often they'll hit. There's a good reason the predictions for the upcoming US Westcoast major earthquake is always given within the span of centuries.
  - sandworm101 9y ago
    To harvest energy you need a device on either side of an energy differential. To pull substantial energy from shifting plates you would need something as long, and deep, as those plates. Point devices, ropes being pulled across a slowly separating plate, wouldn't generate much of anything. You would need millions of ropes attached to billions of anchors, all several KM deep within the earth before you could hope to pull any fraction of the energy.
Deestan 9y ago
It would be similar to trying to move a truck by hitting it very very hard with a hammer.
abkfenris 9y ago
The total seismic moment energy for a 8.1 magnitude quake is roughly 1.7 * 10^21 Joules. For comparison, Tsar Bomba (the largest nuke ever built) as tested was around 50 megatons of TNT or 210 Petajoules 2.1 * 10^17. So you would roughly need 8000 Tsar Bombas triggered in just the right pattern to make their force additive in order to release that much energy into the plate. I have a sneaking suspicion that if you could mine all the material for those Tsar Bombas in the same place, isostasy would give you equal or greater response from the plate, but I'm not going to do those equations right now.
- blacksmith_tb 9y ago
  Do you need to put as much energy into an already-loaded system as will be released, though? Compare the energy released by a stack of blocks falling to the amount it takes to topple it. I think it's unlikely we will ever be able to trigger quakes intentionally, but there's some implication fracking to extract natural gas [1] is causing seismic activity, for example. 1: http://time.com/84225/fracking-and-earthquake-link/ http://time.com/84225/fracking-and-earthquake-link/

You might be underestimating the size of even a small tectonic plate. Large explosions will cause seismic waves, of course, but to actually move anything, I believe you'd need a spectacularly big one - bigger by far than anything we've detonated before.

sandworm101 9y ago

My understanding is that the thousands of tiny detectable tremors each day worldwide involve as much energy as several atomic bombs exploding every day. The energy to move hundreds of cubic miles of rock even a nanometer is difficult to imagine.

EwanG 9y ago
Which suggests finding a place with constant tremors might be worthwhile to try to harvest energy from? Possibly just by having a material that generates a current when flexed?
- dmix 9y ago
  It's nearly impossible to predict earthquakes so I don't see how this could be feasible at all. Scientists have been trying hard for decades with no luck. It's been one of the most impenetrable natural phenomenons. At most you get decade+ long likelihoods of the number of earthquakes of x strength, across a very large geographic area. Even in places with a high number of them it's very challenging to give probabilities of when, where, or how often they'll hit. There's a good reason the predictions for the upcoming US Westcoast major earthquake is always given within the span of centuries.
- sandworm101 9y ago
  To harvest energy you need a device on either side of an energy differential. To pull substantial energy from shifting plates you would need something as long, and deep, as those plates. Point devices, ropes being pulled across a slowly separating plate, wouldn't generate much of anything. You would need millions of ropes attached to billions of anchors, all several KM deep within the earth before you could hope to pull any fraction of the energy.

Deestan 9y ago

It would be similar to trying to move a truck by hitting it very very hard with a hammer.

abkfenris 9y ago

The total seismic moment energy for a 8.1 magnitude quake is roughly 1.7 * 10^21 Joules. For comparison, Tsar Bomba (the largest nuke ever built) as tested was around 50 megatons of TNT or 210 Petajoules 2.1 * 10^17. So you would roughly need 8000 Tsar Bombas triggered in just the right pattern to make their force additive in order to release that much energy into the plate. I have a sneaking suspicion that if you could mine all the material for those Tsar Bombas in the same place, isostasy would give you equal or greater response from the plate, but I'm not going to do those equations right now.

blacksmith_tb 9y ago
Do you need to put as much energy into an already-loaded system as will be released, though? Compare the energy released by a stack of blocks falling to the amount it takes to topple it. I think it's unlikely we will ever be able to trigger quakes intentionally, but there's some implication fracking to extract natural gas [1] is causing seismic activity, for example. 1: http://time.com/84225/fracking-and-earthquake-link/ http://time.com/84225/fracking-and-earthquake-link/