How many nukes would it take to cause a tsunami if they were planted on the ocean floor?

Question

Damn! There goes my conspiracy theory. Right out the window. lol!

Answer 1

Here, you can see for yourself:

Richter TNT for Seismic Example
Magnitude Energy Yield (approximate)

-1.5 6 ounces Breaking a rock on a lab table
1.0 30 pounds Large Blast at a Construction Site
1.5 320 pounds
2.0 1 ton Large Quarry or Mine Blast
2.5 4.6 tons
3.0 29 tons
3.5 73 tons
4.0 1,000 tons Small Nuclear Weapon
4.5 5,100 tons Average Tornado (total energy)
5.0 32,000 tons
5.5 80,000 tons Little Skull Mtn., NV Quake, 1992
6.0 1 million tons Double Spring Flat, NV Quake, 1994
6.5 5 million tons Northridge, CA Quake, 1994
7.0 32 million tons Hyogo-Ken Nanbu, Japan Quake, 1995; Largest Thermonuclear Weapon
7.5 160 million tons Landers, CA Quake, 1992
8.0 1 billion tons San Francisco, CA Quake, 1906
8.5 5 billion tons Anchorage, AK Quake, 1964
9.0 32 billion tons Chilean Quake, 1960
10.0 1 trillion tons (San-Andreas type fault circling Earth)
12.0 160 trillion tons (Fault Earth in half through center,
OR Earth's daily receipt of solar energy)
[See source.]

The 2004 Indonesian tsunami that covered the Indian Ocean was a Richter 9.0 quake. [See source.] So that equates to 32,000 megatons of energy. Or 1,000 times more than the largest thermal nuclear device cited above for the Richter 7 quake.

Now, understand this...the mere presence of 32,000 megatons of energy going off at once will not guarantee a tsunami. For one like the Indonesian tsunami, the devices would need to collapse the sea floor, which the water would rush in to fill. And then, rebounding from that rush to fill the crater, a crest would form the tsunami wave.

Answer 2

The Tsar Bomb which is the largest nuke ever tested (50 M tonnes) created an earthquake of magnitude 5.2. And this was detonated 4000 m above sea level.

If that bomb was detonated on the ocean floor, the magnitude would have been more like 7. If it is planted deep enough in the ocean floor it should generate a tsunami.

Answer 3

I don't think it's possible......unlike the earthquake that caused the tsunami, the nukes would simply vaporize all the water around it, not actually create energy waves enough to make a tsunami....just go on youtube and check out some of the test videos they shot.

Answer 4

just one, since the origin of all coastal waves can be caused by a single disturbance of the sea floor. one big disturbance would cause one big wave. at the origin of the blast, the change of the surface wave would be very minimal, depending on how deep the blast was, and as the wave travels into shallower waters, the amplitude of the wave increases in order to conserve energy and momentum.

the deeper you plant the nuke, and the farther out from land you make the blast, the higher the tsunami will be when it reaches land.

Answer 5

Just one. Figure about a 50 megaton burst.