What would happen if 250 nuclear weapons were detonated within Owens Valley in California?

Question

(NO CIA/FBI/NSA IM NOT A TERRORIST ARMED WITH 250 STOLEN/UNACCOUNTED FOR NUKES)

I’m writing a Godzilla fanfiction and in it, while Godzilla was doing Godzilla things on the West Coast (destroying cities, fighting and brutally killing other Kaiju, forcing humanity towards extinction, etc.), the US was finally forced to deploy nuclear weapons against the gargantuan nuclear monster in an attempt to annihilate Godzilla (even though in my story Godzilla has historically easily and effortlessly tanked the Castle Bravo “test”, the Tsar Bomb “test”, the Vela Incident, etc.). This became infamously known as “Operation Ragnorak.

Anyway, the US military was able to lure Godzilla into Owens Valley in eastern California and when the giant nuclear Kaiju was at the deepest point of the Valley, 250 nuclear weapons were launched directly at and within the direct vicinity of Godzilla himself (he survived obviously). Of the 250 nuclear weapons used against Godzilla, most of them were composed of W-87s, W-78s, W-88s, W-59s, and a few B-83s. They were all detonated in sequence, with most of them being deployed from land-based nuclear silos, ICBMs, nuclear submarines, and a few bomber-based aircraft (the first phase of Operation Ragnorak also utilized nuclear missiles that were turned into makeshift nuclear mines).

But what would geologically and ecologically happen to not just Owens Valley but also the Southwestern US? What would be the direct result of detonating 250 nuclear weapons within a small, confined, narrow strip of land? And what ideal situation would occur where the US isn’t wiped out as a country but there’s still the mass deployment of nukes against Godzilla?

Answer 1

Consequences Not Too Bad, Considering

The average warhead in the US nuclear arsenal, dialed to full-yield, is 200kt. We'll assume that most of the weapons used approximate that. You have specified that a few of the big boys are being employed, though, so:

NukeMap of the consequences of a 1.2MT bomb in Owens Valley.

The biggest of the bombs is going to throw fallout the highest, generate the most (as I assume no one is bothering with dirty bombs), and create the biggest fireball. Both the NukeMap and the rest of my estimations are assuming groundburst for all utilized weapons, as overpressure and area destruction is not the goal.

So the fallout plume from the W83s extends well over mid-Nevada (ironically, not over the Nevada Testing Site!), but not really much further, and most of the plume would just require that people in the area take iodine supplements for a few weeks afterwards. Remediation of the rest of the fallout would be a process, but not too dramatic a process.

Estimated fatalities from the biggest bombs in that location ~30, total injuries ~410. There would be a statistically measurable uptick of cancers globally, since 250 bombs would be more in-atmosphere detonations than the US has ever performed, and at substantially greater megatonnage.

Nothing geologically would happen. Assuming the average of 200kt per bomb, 250 such bombs is only about 50MT. In comparison, Mt. St. Helens was a 24Mt detonation, all at once... and it didn't permanently do anything other than make the top of the mountain into a crater. You've got a bunch of sequential explosions. There'd be some weird cratered terrain at ground zero, and the nearby walls of of the valley would take a beating... and that's it.

Ecologically, you'd be throwing up a fair amount of fallout, but even assuming no human remediation, this is still less than a tenth of the total megatonnage detonated on earth in the course of nuclear testing. The US would be barely affected, physically. Obviously, mentally, there'd be a lot of trauma.

(Not to mention, an enormous number of questions lobbed at the military leaders who kept using nukes after it was apparent that they weren't working.)

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To compare, Tsar Bomba, which you namedropped, was about equal in yield to your entire attack. Here's the island it was dropped on.. You can see the scars, but if you weren't told that was where it happened, you wouldn't even know.

Edit the second - I'm assuming that the fact that Godzilla survived both Tsar Bomba and Castle Bravo isn't broadly known or known at all to the targeteers whose job would be deploying the nuclear devices, or they wouldn't do it. The people responsible for initiating nuclear devices are very aware of what they're capable.

Answer 2

There's a chance your detonations could set off tectonic faults in Owens Valley.

In 1872 there was an estimated 7.8-7.9 magnitude quake that killed 27 people, or 10% of the population in the valley. https://en.wikipedia.org/wiki/1872_Owens_Valley_earthquake

The explosions might be enough to trigger the fault again, especially if Godzilla's route matched the fault.

Here's an estimated map of the land offset from https://seismo.berkeley.edu/blog/2019/03/26/today-in-earthquake-history-owens-valley-1872.html

Imagine the plot value of Godzilla walking a line of nuclear attacks, to succumb to an earthquake triggered by those quakes. Perhaps the fault separates, drops him in, and then closes

Answer 3

Maximise collateral damage by creating an earthquake

The military aren't entirely stupid. They've recognised that just dropping a nuke on Godzilla isn't going to work, and even a succession of nukes might not do it. So in the face of opposition which their weapons can't hurt, they have to go lateral. And with the extinction-level threat that Godzilla represents, there's basically no upper limit on collateral damage that can't be justified.

The West Coast is famously full of tectonic fault lines. A solid earthquake has more energy than any nuke, and (as previously noted in another answer) the Mount St Helens eruption put out more energy than the entire US nuclear arsenal. So some modern-day Barnes Wallis suggests, "Can we blow through the crust, drop the kaiju in the hole, and have it crushed to death in the resulting earthquake?" (Top tip, by the way: Never underestimate the ability of the Brits to put a fuck-ton of explosives to good use. We may talk fancy, but we're a nation of complete nutjobs.)

This isn't even hypothetical, by the way. US underground nuclear testing has already triggered faultline movement, ironically enough in a test called Faultless. So we absolutely know it can be done. The only question is exactly what size of bomb you need to make it happen, which thankfully is something no country has experimented with. Yet.

Enter the nuclear bunker buster. There are still plenty in the US stores, and I wouldn't bet against some researchers still working on new versions somewhere in real life, never mind for fictional plot purposes.

For best results, it seems likely that they wouldn't actually aim at Godzilla. Instead they'd land multiple nukes along the faultline, fuzed to detonate at exactly the same time (and with modern electronics, "exactly the same time" can be accurate to the microsecond). You naturally want a delayed fuze anyway to explode underground. And you just make sure Godzilla is in the middle of the faultline when you do it.

The outcome? Basically a really, really big hole.

The hole truth

How big? In Britain, the bombing range used to test Tallboy bombs, the original Barnes Wallis bunker-busters, still exists and is part of a National Park. (Yes, the village next door is called Sandy Balls. Also don't underestimate the ability of the Brits when it comes to comedy names for places.) From a 5-ton bomb, the crater was 130ft in diameter and 70ft deep. The W88 nuclear bunker-buster for comparison is roughly 95,000 times bigger at 475 kilotons. Let's assume the 5-ton Tallboy produced a 65ft-radius hemispherical hole, and assume volume "excavated" scales with payload - that gives you 3000ft-radius holes. 6000ft wide, 3000ft deep. Let's round down and say the hole is a mile wide and a half-mile deep. According to Google Maps, Owens Valley is around 4 miles wide. 4 bunker busters in a row would then basically guarantee you a hole the width of the valley. And half a mile deep, of course.

How many W88s do we have? Wikipedia says "~400". Let's assume 200 for the OP's question. Suitably spaced, that gets us a hole 4 miles wide, 50 miles long, and half a mile deep. That's probably going to kick off some very interesting tectonic effects, for sure. And Godzilla is going to be one severely pissed off kaiju.

About that collateral damage...

It also gives you 54.6 billion cubic feet of soil thrown into the air per bomb. For 200 bombs, that's 22 trillion cubic feet, or 74 cubic miles. For comparison, Krakatoa only managed to spit out around 12 cubic miles of volcanic ash, and it did significant damage to the world's agriculture for several years. That soil is also going to be highly radioactive - I wouldn't even like to guess at the outcome there, considering Chernobyl put relatively little fallout into the air with rather significant long-term effects.

The nuclear fallout is only the start though. The whole idea of this is to create tectonic effects. If we suppose that this does actually result in an man-made volcano, the end result could be even worse - and what gets thrown up by the volcano isn't just going to be volcanic dust, it's going to be heavily-irradiated volcanic dust. You can most likely say goodbye to California for human habitation for quite some time; but it could quite easily scale up to On The Beach levels of worse. In short, pretty much any level of outcome that fits with your plot can be believably thrown into this scenario, up to and including the end of humanity.

And that's before you remember that you still have to deal with Godzilla.

(Edit: I'd managed to misquote the W88 as 475 tons, not 475 kilotons, when I did my sums. With the correct value, this becomes truly apocalyptic.)

Answer 4

The answers about tectonic activity seem to me to be totally unmoored from any scientific basis. It's true that the energy scales for earthquakes and nuclear weapons are comparable. For example, a Richter 7 quake is the equivalent of about half a megaton of TNT. However, both an earthquake and a bomb are highly localized releases of energy. Seismic energy will radiate out in all directions, with the energy density falling off like 1/r^2 for longitudinal waves and 1/r for transverse (surface) waves. There is no reason to imagine that this energy would be focused in such a way as to make a fault slip or something.

Jdunlop beat me to it with the nukemap simulation of fallout. However, note that the simulation just assumes some direction for the wind, and the direction it assumed was the least harmful one possible. If it's blowing toward SF or LA, there's a problem.

Depending on various factors, this might set off catastrophic wildfires in the Sierra. The amount of ash released might be enough to have serious consequences, like a miniature nuclear winter. Agriculture in California might be stopped for years.

LA is dependent on the Owens Valley for a lot of its water, and there are serious concerns about how the water pipelines would likely fail in a big earthquake. Even if the water kept flowing, I'm not sure Angelenos would want to drink it.

General disruption of society and the economy would presumably be worse than, e.g., Hurricane Katrina. If trucks stop rolling into LA, people are going to starve to death.

Answer 5

THIS WOULDN'T JUST HAVE EFFECTS ON THE LAND, IT WOULD HAVE EFFECTS ON GODZILLA

As seen in Godzilla; King of the Monsters, Godzilla is powered by nuclear energy. A nuke blowing up in his face actually made him stronger, after it healed his crippling wounds in a matter of moments. If he was at full strength and at ground zero of 250+ nuclear detonations...

Well, we've seen what happens when Godzilla goes 'super-critical'; he becomes so radioactive he melts metals that are near him, and he got there WITHOUT the help of a few hundred nukes. That much ordinance launched at Godzilla would push him WAY beyond the 'super-critical' state seen in the above movie.

The upshot of all this? Not only would the nukes irradiate the valley in question forever, but it would also make Godzilla a billion times more powerful and possibly reduce the entire state of California, and a sizeable chunk of the neighboring states, to a gigantic pot of molten, radioactive slag as a result.