A satirical story making the rounds on social media claims that 78% of French people would throw a bomb into the Auvergne volcano crater to see what happened.
The story, published on Le Gorafi, is entirely fictitious. It says the vast majority of French people would throw a "very big bomb" into the volcano craters. It said people would want to be far away from the crater, but be able to take "cool photos" because it would be "really trippy."
"Lots of countries have volcanoes that work, why not us?" pondered one imaginary person.
However, the idea of bombing volcanoes got IBTimes UK thinking – what would happen if you threw a bomb into a crater?
Interestingly, the idea of bombing a volcano was once suggested in a 1944 Popular Science article as a way of defeating the Japanese during WWII. The idea was also bandied around later as a way to divert lava flows.
Bombing an already erupting volcano
Erik Klemetti, volcanologist and petrologist at Denison University and writer of Eruptions on Wired Science, wrote in a blog in 2011: "Why am I going to talk about bombing volcanoes? Well, because it is exciting."
He said he has never found evidence of anyone bombing a volcano to stop it erupting because "it would never work." In terms of redirecting lava flow, he said there have been a few examples from the US, and one when Mount Etna in Italy was erupting.
Concrete blocks were used to bomb the volcano to save a nearby town: "In 1992, lava flows threatened Zafferana Etnea, a small town on the flanks of Etna. This time attempts to divert the lava included dropping concrete blocks on the lava flows so as to block it from flowing towards the town.
"The plan was to blow a hole in a lava tube at higher elevations and then fill the lava tube with concrete blocks to stop the flow of lava in the tube. Once lava can move down a lava tube, it is very well insulated - so much so that the lava inside the tube can stay hot and move quickly downslope, to the point where it can actually thermally eroded (melt) the bottom and sides of the lava tube, thus making it bigger.
"By punching a hole in the tube and filling it with debris, the hope was to stop this from occurring. The 'bombing' of the flow was a mixed success - it was unclear how much the diversion actually worked, but the towns were spared - but the question of whether diverting lava flows at Etna is a good idea is still up in the air."
He concludes that bombing a volcano to divert lava flow can work, but only if the right location is chosen.
Would a bomb make a volcano erupt?
In short no. In a later blog post for Wired, Klemetti explains that the vast majority of conspiracy/fictional ideas of how to get a volcano to erupt involve throwing a device like a nuclear bomb into a volcano.
He notes that explosive volcanic eruptions take place because of pressure changes – like a champagne bottle with a cork. Fast release of this pressure causes an eruption. The other way eruptions occur is when outside water is involved in the equation, which makes it more explosive.
If the right ratio exists, the mix of magma and water can be self-sustaining, so the explosive eruption can continue until either one runs out.
However, he notes: "The fictional methods to get a volcano to erupt really don't help in any of the scenarios. Typically you see the evil genius picking a volcano that isn't showing signs of activity, so he/she is already showing up to the gunfight without bullets. The 'bomb into the volcano' doesn't really address the pressure issue as the explosions don't remove enough of the overlying rocks to release that lithostatic pressure."
What about a nuclear bomb to stop an eruption?
This question was covered by chemist and author Keith Veronese in a 2012 blog for io9. He said internet lore says dropping a nuke on an erupting volcano would stop an eruption – but this is not the case either.
While no one has tried it – and no country is likely to – there are several scenarios for the outcome, depending on where the bomb is placed. In terms of heat, "the nuclear blast should provide a sufficient temperature to boil the magma, vaporising it along with enough heat to cause a phase transition of the surrounding rock to vaporise it as well."
However, he said the heat from the lava would probably melt the warhead and radioactive material, preventing a full detonation.
If the bomb was placed at the volcano base, the heat might blow a hole in the side of the volcano, allowing more lava to flow out afterwards. If placed at the opening of the volcano, the lava would probably be vaporised and it could technically "plug" the chamber. However, this scenario would be "highly unlikely". More realistically, it would just crush part of the top of the volcano.
"Nuclear devices don't appear to be an option to halt an eruption, just an option by which to cause an eruption ... Let's just keep nuclear weapons away from volcanoes (even if your intentions are solely humanitarian), OK?"