North Korean Nuclear Test Site Has Collapsed, Explaining Kim's "Suspension" Of Further Tests

It finally happened.

Six months after a group of Chinese scientists warned that the North Korean Punggye-ri nuclear test site was on the verge of collapse, and following reports from Japan's Asahi TV that more than 200 North Koreans had died when a tunnel collapsed at the test site, the South China Morning Post reported today that North Korea’s mountain nuclear test site has completely collapsed, putting China and other nearby nations at unprecedented risk of radioactive exposure, two separate groups of Chinese scientists studying the issue have confirmed.

The collapse also likely explains the sudden willingness of North Korean leader Kim Jong-un to declare last Friday that he would freeze the state’s nuclear and missile tests and shut down the site, a researcher cited by the SCMP said.  

At least five of North Korea's last six nuclear tests all took place under Mount Mantap at the Punggye-ri nuclear test site in North Korea’s northwest; in the process they unleashed artificial earthquakes and destabilized the mountain to the point of no return.

According to the SCMP report, a group of researchers found that the most recent blast tore open a hole in the mountain, which then collapsed upon itself. A second group concluded that the breakdown created a “chimney” that could allow radioactive fallout from the blast zone below to rise into the air.

A research team led by Wen Lianxing, a geologist with the University of Science and Technology of China in Hefei, concluded that the collapse occurred following the detonation last autumn of North Korea’s most powerful thermal nuclear warhead in a tunnel about 700 metres (2,296 feet) below the mountain’s peak. The test turned the mountain into fragile fragments, the researchers found.

The mountain’s collapse, and the prospect of radioactive exposure in the aftermath, confirms a series of exclusive reports by the South China Morning Post on China’s fears that Pyongyang’s latest nuclear test had caused a fallout leak. The scientists warned that radioactive dust could escape through holes or cracks in the damaged mountain.

“It is necessary to continue monitoring possible leaks of radioactive materials caused by the collapse incident,” Wen’s team said in the statement.

As the SCMP notes, the official findings will be published on the website of the peer-reviewed journal, Geophysical Research Letters, likely next month.

North Korea saw the mountain as an ideal location for underground nuclear experiments because of its elevation – it stood more than 2,100 meters (6,888 feet) above sea level – and its terrain of thick, gentle slopes that seemed capable of resisting structural damage.

While the mountain’s surface had shown no visible damage after four underground nuclear tests before 2017, the 100-kilotonne bomb that went off on September 3 vaporised surrounding rocks with unprecedented heat and opened a space that was up to 200 metres (656 feet) in diameter, according to a statement posted on the Wen team’s website on Monday.

And as shock waves tore through and loosened more rocks, a large section of the mountain’s ridge, less than half a kilometre (0.3 mile) from the peak, slipped down into the empty pocket created by the blast, leaving a scar visible in satellite images. Wen concluded that the mountain had collapsed after analysing data collected from nearly 2,000 seismic stations.

Three small earthquakes that hit nearby regions in the wake of the collapse added credence to his conclusion, suggesting the test site had lost its geological stability.

A second team led by Liu Junqing at the Jilin Earthquake Agency with the China Earthquake Administration in Changchun reached similar conclusions to the Wen team.

The “rock collapse … was for the first time documented in North Korea’s test site,” Liu’s team wrote in a paper published last month in Geophysical Research Letters. The breakdown not only took off part of the mountain’s summit but also created a “chimney” that could allow fallout to rise from the blast centre into the air, they said.

Zhao Lianfeng, a researcher with the Institute of Earth Science at the Chinese Academy of Sciences in Beijing, said the two studies supported a consensus among scientists that “the site was wrecked” beyond repair. “Their findings are in agreement to our observations,” he said. “Different teams using different data have come up with similar conclusions,” Zhao said. “The only difference was in some technical details. This is the best guess that can be made by the world outside.”

As we reported previously, speculation grew that North Korea’s site was in trouble when Lee Doh-sik, the top North Korean geologist, visited Zhao’s institute about two weeks after the test and met privately with senior Chinese government geologists. Although the purpose of Lee’s visit was not disclosed, two days later Pyongyang announced it would no longer conduct land-based nuclear tests.

Hu Xingdou, a Beijing-based scholar who follows North Korea’s nuclear programme, said it was highly likely that Pyongyang had received a stark warning from Beijing.

“The test was not only destabilising the site but increasing the risk of eruption of the Changbai Mountain,” a large, active volcano at China-Korean border, said Hu, who asked that his university affiliation not be disclosed for this article because of the topic’s sensitivity.

The mountain’s collapse has likely dealt a huge blow to North Korea’s nuclear programme, Hu said.

Hit by crippling international economic sanctions over its nuclear ambitions, the country might lack sufficient resources to soon resume testing at a new site, he said.  “But there are other sites suitable for testing,” Hu said. “They must be closely monitored.”

Guo Qiuju, a Peking University professor who has belonged to a panel that has advised the Chinese government on emergency responses to radioactive hazards, said that if fallout escaped through cracks, it could be carried by wind over the Chinese border.

“So far we have not detected an abnormal increase of radioactivity levels,” Guo said. “But we will continue to monitor the surrounding region with a large [amount] of highly sensitive equipment and analyse the data in state-of-the-art laboratories.”

Zhao Guodong, a government nuclear waste confinement specialist at the University of South China, said that the North Korean government should allow scientists from China and other countries to enter the test site and evaluate the damage.

* * *

It remains unclear what if any impact the news will have on Trump's eagerness to sit down with Kim and discuss a denculearization of North Korea, if it emerges that the rogue nation only agreed to negotiate because it no longer had the ability to conduct further tests, and thus had no more leverage, as opposed to a voluntary decision by Kim Jong Un.


edotabin T-NUTZ Wed, 04/25/2018 - 15:31 Permalink

For the last time: Ding Dong is shit. His regime is shit. The reason for regime's existence is shit. The way they govern is shit. They epitomize shit.

I'm very glad his puss-filled brain was squeezed like a pimple with the only thing he is capable of understanding (credible threats). He folded like the cheap tent that he is.

The larger powers should also stop hiding behind NK and get together to show those people a better way forward.

In reply to by T-NUTZ

land_of_the_few nmewn Thu, 04/26/2018 - 03:13 Permalink

Just a thought- maybe it's because it's *not true*. 

"DPRK’s Closing the Punggye-ri Nuclear Test Site: No, it is not a Case of Passing Off Damaged Goods"

"On April 20, North Korea made the dramatic announcement[1] of several decisions that included suspending further nuclear and missile tests and that its “nuclear test center would be discarded in order to ensure the transparency of the suspension of the nuclear test.[2] A number of analysts, including a Washington Post column by Max Boot on Saturday, mistakenly dismiss the offer by claiming that the test site is probably unusable anyway."

"In short, there is no basis to conclude that the Punggye-ri nuclear test site is no longer viable for future nuclear testing."

"There remain two portal areas located in more pristine competent rock that can be used for future tests if Pyongyang were to give the order. Whether that will stay an option will depend on reaching verifiable agreements that build on Pyongyang’s pledge to shut down the facility."

In reply to by nmewn

Ghost who Walks land_of_the_few Thu, 04/26/2018 - 04:03 Permalink

Your points are well made about a lack of independent review. However look up a mining technique called "Block caving".

In a lot of underground mining the preferred technique is to come in below the targeted rock zone and then mine upwards. This means that after each blast in a "rise" the rock falls to the bottom where it can be accessed and loaded out.

If you use this technique to create a test shaft for a nuclear weapon you run the risk of fracturing all the rock to the surface which collapses to form a "block cave" , when you fire the nuclear weapon.

This "block caving" technique is used in a few modern underground mines which have high up-front capital costs, as there is a lot of tunnelling and then conventional blasting before the cave forms to the surface and then continues to feed the bottom draw points.

Nuclear explosives have a unique property compared to conventional explosives of a very high Velocity of Detonation which exceeds the natural speed of sound in the rock and causes the rock to fail first in compression and then when the shock wave hits the top of the mountain it will be reflected as a tension wave and this will chew up more rock as rock only has one seventh of the strength in tension compared to compression.

Some Gold that got to the west during the period of the Soviet Union was found to have low levels of radioactivity and rumours of mining Gold in the Kolyma region using nuclear explosives surfaced. I recall this from "New Scientist" at the time.

So its not necessary to actually inspect the site to confirm the truth of the matter. The US Government has very accurate Digital Terrain models of the test area which come from Synthetic Large Aperture Radar scans.

The US has experts in both nuclear explosives and mining who can run models to see what the risk of a failure to the surface is based on their past data from tests in Nevada.

The experts only have to assume that the drive from the portal is level or slightly uphill to aid drainage of water and then check the spot height at the portal and compare that to the Digital terrain model. That will give the thickness of rock. They probably know the rock type and its compressive strength, Young's Modulus and Poisson's Ratio. If they don't have actual rock data they can still model in a range to see if the mountain might fail. New phrase for you "This is Rock science" and you don't need to be a Rock Scientist to understand the concepts.

Edit: On further contemplation of the problem, they should be able to check before and after SLA Radar scans of the area that will show any large ground movements, the area of the movement and the actual drop. I am not familiar what Radar Satellites are available to the US at present. By averaging the data from several scans and using special processing techniques the scientists can detect movement at from 2 to 10mm

In reply to by land_of_the_few

zimboe Rainman Thu, 04/26/2018 - 04:18 Permalink

So , therefore, Trump didn't actually make Kim "Cheese-Monster" Un (cheese fears him), come to heel, it was just that his mountain wore out like a condom with 100 Thai whore cycles on it.

Gosh. Imagine that.



Christ on a skateboard.

What a pile of liberal treasonous flaming clownshoe crap stuffed with horse biscuits, in a dumpster, aflame.

Human decency demands his graceless death at once.


Burn this worthless greedy pig of a cheese-gobbling brandy-quaffing greedhead, stuffing his bloated hog's belly, as his citizens starve.

He belongs on the barbie, roasting:  Hot, fat, and juicy, bloated with savory steam, flavoured with the best French brandy and cheesy goodness.


Shit, Kim gotta be really good eating by now. Better than Kobe Beef.

He's soon be on that spit, with lots of drippin's for gravy, on the grill of justice.

He deserves to be eaten.

And you can bet those sweet drippin's won't go to waste.




Then we can see clear to get these poor starving bastards some God-Damned decent food.

About a million boxes of good old Kraft Mac and Cheese should help.

They'll love it. They'll honk it down with all speed.

Sure they will. All you need is hot water.


In reply to by Rainman

caconhma T-NUTZ Wed, 04/25/2018 - 13:31 Permalink

Well, N. Korea has never signed an agreement to stop nuclear testing in the atmosphere. They can always do it over the Pacific ocean.

But then the USA will have difficulties to know whether it is just a test or it will go all-way to the US West Coast.

In reply to by T-NUTZ

HRClinton Truther Wed, 04/25/2018 - 13:29 Permalink

OMG, you mean I called it 2 days ago? I should be Kewish about it, and start charging money for my insight and advice.  😉


HRClinton Chief Joesph Mon, 04/23/2018 - 13:19 Permalink

I read NK's statement as a (((lawyer))) would, and concluded...

1. Given that their current underground site has and is collapsing anyway, they have to suspend all testing and close that facility anyway.

2. Nothing but a national deathwish can/will stop NK from resuming testing when...

a. The new site is ready

b. ZUSA gets too aggressive toward NK

Both sides are playing PR games, for domestic consumption. 

Party on, Wayne.

In reply to by Truther

zimboe Truther Wed, 04/25/2018 - 19:17 Permalink

In an underground test in flat lands as in Nevada, the bomb creates a cavern.

The roof collapses into the hole,and then that new roof collapses in turn, all the way to the surface, forming a broad depression called a "retarc" (crater spelled backwards). Beneath lies a long vertical cylinder of broken rock leading to the explosion point.

They don't usually leak. Much.

Google map the Nevada test site- there are hundreds. Looks like a shotgun blast.


or look here:


Is this collapse in Nork's mountain a retarc? Or something worse?

In reply to by Truther

Moving and Grooving zimboe Wed, 04/25/2018 - 19:44 Permalink

One in particular leaked. Very badly.


Frenchman's Flat was where a lot of the above-ground tests happened. Lots of glass and twisted, rusting towers. Piute Mesa was what the gov't called the main underground test area. Lots of concave depressions, big and small, all crowded together on the mesa top. Cool from the air. I worked at the TTR when underground testing was stopped. A lot of incredibly talented and experienced engineers and technicians slipped through our fingers then, never to return.



In reply to by zimboe

zimboe Moving and Grooving Wed, 04/25/2018 - 20:49 Permalink

I read the Sedan test was a real mess for a long time.

I mean, a 100 kt bomb set to move as much dirt into the air as possible. What could possibly go wrong? Utterly insane by modern thinking. The crater is hot to this day.

Though the slow-motion of it on that Shatner documentary (Atomic Journeys?) showing half a cubic mile of dirt slowly rising in a huge smooth dome, until it blew out in multiple jets of yellow hellfire and tumbling stones as large as buildings, is simply breathtaking.

Also used on one of the Austin Powers flicks as Dr. Evil's base blows up.

Worth checking out, Zedgers, lots of interesting physics can be seen.

In reply to by Moving and Grooving

Deep Snorkeler Wed, 04/25/2018 - 13:05 Permalink

The Benefits of Radiation

1. radiation spurs marine growth and creates new species

2. it invigorates human intelligence

3. increases genital size

4. radiation poisoning is easily cured by blood-letting

and eating beets