Ok hypothetical situation: There is a large underwater earth quake which creates an enormous tsunami that is heading from the mid-Atlantic to the coast of wherever. Or let’s say there is a large landslide off the Canary Islands which creates a wall of water rushing towards the eastern seaboard of the US…irregarless, there is a large wall of water rushing towards a coast threatening millions of casualties.
Could a large multi-megaton nuclear warhead detonated somewhere in the proximity of the wave, dispurse it enough to make it not cause as much damage?
Meteorologists around here actually addressed the question if some sort of nuclear bomb could minimize the damage of a hurricane - the consensus was that not only would a nuclear bomb do nothing to minimize the hurricane’s power, it would have the added disadvantage of making the hurricane radioactive.
I imagine that your tsunami scenario would be much the same.
I imagine that detonating a nuke directly in front of a tsunami would have an effect similar to plunking an island down in front of one. You’d get an area directly behind the island, or nuke, where the wave energy was decreased, but at greater distances, refraction would take over, and the wave would rebuild to something approaching its original height.
Tsunamis aren’t raging walls of water cruising around above the surface until they cross paths with a peaceful fishing villiage. They don’t grow into impressive liquid cliffs until the wave moves into shallow water… much like normal waves. I doubt you’d want to detonate a bomb in front of the wave after it had crested (I.E. directly over the peaceful fishing villiage you’re trying to save).
First: “irregardless” isn’t what you mean here, and it’s only a word by virtue of frequent misuse.
Now, let’s assume for the purposes of maximum effectiveness that you have a MIRVed ICBM like the SS-18, which, according to most accounts, carries 10 reentry vehicles (RVs - the conical package in which the warhead sits). You have several brilliant targeteers who are going to make the RVs land in a line, side by side, so that their radii just barely overlap.
This page tells us how to calculate blast radius and effective energy (in kJ) based on warhead mass. This site lists the blast power of each of those warheads as 750 kilotons. So, we have
r (miles) = (W / 20 ) ^ (1/3) = 3.75 miles give or take. Let’s call it 4 miles to be generous, and that’s the radius of “severe blast damage.” Better yet, let’s call it 3.5 miles, so that the radii overlap a little bit. That gives you a 70 mile wide blast front.
We can treat the next bit from several approaches. We can look at the maximum overpressure that a nuclear blast creates, and determine what pressure would stop a tsunami of height H and forward velocity V. That seems a little hokey to me. I say we look at the total energy released, realize that at most half of it is going to be acting in the right direction, and then compute the kinetic energy of a giant wave.
TNT equivalence is 5.1 kJ /g, so 750,000 tons are 750,000,000,000 grams, which are in turn 3,825,000,000,000 kJ or 3.825 * 10[sup]12[/sup] Joules. There are ten warheads going off, so it’s really ten to the thirteenth, and we’re assuming that only half of their energy is pointed in the right direction, so it’s really 1.913 * 10[sup]13[/sup] Joules.
[url=“http://www.prh.noaa.gov/itic/library/pubs/great_waves/tsunami_great_waves_5.html”]This page says a tsunami can move as fast as 800 km/hr and have a wave height in “extreme cases” of 15m. For our purposes, we’ll assume a 5m tsunami with a roughly triangular cross section – 5m tall, 4m wide at the base, with a flat front caused by air pressure effects of moving so quickly. Just the portion of the wave that we want to stop (the 70-mile wide section) has a length of 112,000m, and a cross section of 10 square meters, or an overall volume of 1,120,000 cubic meters. It’s made of water (discounting fish and salinity) so it has a mass of 1,120,000,000 kilograms, and a velocity of 222 m/s. This gives a kinetic energy of one-half-mass times velocity squared, or:
5.53 * 10 [sup]13[/sup] Joules.
So the wave has significantly more energy than ten nukes, and even if the nukes are perfectly efficient (that is, they don’t waste most of their energy heating the water - which they would!) you’re still not really going to make much of a dent. Also, a tsunami that large is going to have a wave front much wider than 112 km.
Plus, even if you were able to cancel out or weaken the tsunami, you’d still be stuck with part of the blast shockwave that doesn’t point toward the tsunami.
