Deterrence
Re: Deterrence
No more low intensity seismic shocks in Pak in the past couple of months ?
Re: Deterrence
The frequency’s the same as before — nothing unusual. They’ve just dropped out of the news cycle because there’s no real significance to report (as have been posted a few times here in details).
Re: Deterrence
https://www.ndtv.com/world-news/china-c ... s-10966774
No idea about the veracity of this claim as the US may just be trying to do unglee and in all likelihood doing the same thing or sub critical tests.
From the article:
No idea about the veracity of this claim as the US may just be trying to do unglee and in all likelihood doing the same thing or sub critical tests.
From the article:
From AI:"China has conducted nuclear explosive tests, including preparing for tests with designated yields in the hundreds of tons... China has used decoupling - a method to decrease the effectiveness of seismic monitoring - to hide its activities from the world.
How is this any different from how India tested or any underground nuclear test?Overview of Nuclear Testing by Decoupling
Decoupling is a method used in nuclear testing to reduce the seismic signals generated by an explosion. This technique allows a country to conduct a nuclear test while minimizing detection by monitoring systems.
How Decoupling Works
Mechanism
Underground Cavities: A nuclear device is detonated in a large, deeply buried cavity. This setup absorbs much of the explosive energy, which reduces the seismic waves that escape into the Earth.
Seismic Wave Reduction: The energy from the explosion increases gas pressure in the cavity, which can significantly muffle the seismic signals. This makes it harder for monitoring stations to detect the test.
Re: Deterrence
The American need to involve ALL nuclear powers in Nuclear Arms Limitation talks is the driver for all current noise.
Re: Deterrence
Decoupling isn’t magic stealth. It can reduce seismic signals by maybe 10–50× for very low-yield shots, not make “hundreds of tons” invisible. Even a well-decoupled test at that scale should show up on regional/CTBTO seismic networks, and usually radionuclide stations too.
India’s tests weren’t decoupled and were detected immediately — so comparing the two actually weakens the claim.
Subcritical tests are a different beast altogether (zero yield, legal under CTBT, done by everyone including the US).
My take: Without public seismic or xenon data, this looks more like political signaling than a demonstrated nuclear test.
India’s tests weren’t decoupled and were detected immediately — so comparing the two actually weakens the claim.
Subcritical tests are a different beast altogether (zero yield, legal under CTBT, done by everyone including the US).
My take: Without public seismic or xenon data, this looks more like political signaling than a demonstrated nuclear test.
Re: Deterrence
AmberG : is it possible to provide a brief semi technical explanation of what is decoupling and how it differs from an underground test?
The AI explanation is either vague or wrong…
The AI explanation is either vague or wrong…
Re: Deterrence
Yes, may be important technical distinction being blurred there.
Decoupling is fairly known concept - detonating a device in a large underground cavity reduces seismic coupling to surrounding rock. In ideal conditions, it can suppress seismic amplitudes by roughly a factor of 10–70, depending on geology and cavity size. (Decoupling involves detonating a device in a large underground cavity. The air or empty space inside the cavity acts as a cushion, ensuring the pressure on the surrounding rock walls remains below its elastic limit)
But It does not eliminate seismic signals. ( “Decoupling” isn’t invisibility cloak)
- It works best only for very low-yield tests (tens of tons TNT equivalent).
It requires large, carefully engineered cavities, which themselves leave observable signatures (tunneling, spoil piles, etc).
Most importantly for “hundreds of tons” yield, even a well-decoupled test would still be detectable by regional and teleseismic networks, especially with today’s IMS density.
So the phrase “hide its activities from the world” physics wise does not make sense.
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India’s 1974 and 1998 tests were fully coupled underground tests, not decoupled cavity shots. produced clear seismic signals, detected internationally within minutes.
--
Subcritical tests are a red herring herent they produce zero nuclear yield by definition. (They are conducted by the US, Russia, China--including at Nevada and Lop Nur - are not prohibited under the CTBT.
If the activity were subcritical, seismic signature (and radio nuclei tests) will be a little different from nuclear explosion.
Calling it a “nuclear explosive test” would be technically incorrect.
-- What I think-
- No nuclear test — claim is political signaling (most likely).
(or Subcritical experiments being rhetorically upgraded.
(or Very low-yield hydronuclear experiment (borderline, still hard to hide). or Hundreds-of-tons decoupled test — least consistent with available evidence)
In short -
Decoupling is real, but it doesn’t make nuclear tests invisible — especially not at “hundreds of tons.”
India’s underground tests were fully detectable and fundamentally different.
Without open seismic or radionuclide data, the claim remains political, not scientific.
A good reference for decoupling and other such topics for those with detailed technical detailals:
The Comprehensive Nuclear Test Ban Treaty: Technical Issues for the United States (2012)
Chapter: APPENDIX E Dealing with Evasive Underground Nuclear Testing
(I think you can access the appendix E at:
https://www.nationalacademies.org/read/12849/chapter/13)
Last edited by Amber G. on 08 Feb 2026 04:10, edited 1 time in total.
Re: Deterrence
https://link.springer.com/chapter/10.10 ... -0419-7_17
Dealing with Decoupled Nuclear Explosions under a Comprehensive Test Ban Treaty
The detonation of nuclear explosions in huge underground cavities so as to muffle or decouple the seismic waves they generated has been debated for more than 35 years. This paper reviews the history of the decoupling concept, assesses what countries have the technological capabilities to carry out such a test of a given yield, and evaluates several decoupling scenarios. I conclude that testing with huge decoupling factors, DF, is feasible for yields of a few kilotons (kt) or larger only in cavities in salt domes. Past nuclear explosions conducted in salt that are large enough for the full decoupling of explosions with yields ≥ 0.5 kt are concentrated in only a few areas of Kazakhstan and Russia. The existence of all cavities of that size that were created by past explosions is known since the events that created those cavities must be at least 20 times larger in yield than the size of a fully decoupled event that can be detonated in them. Monitoring of cavities created in that way that may remain standing should be relatively easy at the 1 kt level if appropriate verification measures are put in place. While large cavities can be created in salt by solution mining, no country is known to have evacuated the brine from such a cavity and then conducted a decoupled nuclear explosion in it. Air-filled cavities in salt suitable for significant decoupled testing are stable over only a very narrow range of depths from about 200 m to a maximum of 900 to 1300 m. Most areas of thick salt deposits in the Former Soviet Union and the U.S. are typified by efficient transmission for seismic waves and low natural seismic activity. The scaled cavity radius of 20 m cited in the literature for full decoupling in granite is poorly determined, probably is too small, and has resulted in overestimates of the potential to employ cavities in hard rock for decoupled nuclear testing. For cavities in hard rock, lack of any known experience in conducting decoupled nuclear testing in them, insuring containment in the presence of large differences in principal stresses and the presence of joints and other inhomogeneities on a scale of 1 to 100 m, and the excavation of such a large cavity without being detected are factors that make clandestine decoupled testing of a few kt or larger very unlikely for sites in hard rock, even for countries with considerable testing experience. Decoupled testing of large DF in any media at such yields by countries lacking containment experience would be difficult to carry out in secrecy.
Dealing with Decoupled Nuclear Explosions under a Comprehensive Test Ban Treaty
The detonation of nuclear explosions in huge underground cavities so as to muffle or decouple the seismic waves they generated has been debated for more than 35 years. This paper reviews the history of the decoupling concept, assesses what countries have the technological capabilities to carry out such a test of a given yield, and evaluates several decoupling scenarios. I conclude that testing with huge decoupling factors, DF, is feasible for yields of a few kilotons (kt) or larger only in cavities in salt domes. Past nuclear explosions conducted in salt that are large enough for the full decoupling of explosions with yields ≥ 0.5 kt are concentrated in only a few areas of Kazakhstan and Russia. The existence of all cavities of that size that were created by past explosions is known since the events that created those cavities must be at least 20 times larger in yield than the size of a fully decoupled event that can be detonated in them. Monitoring of cavities created in that way that may remain standing should be relatively easy at the 1 kt level if appropriate verification measures are put in place. While large cavities can be created in salt by solution mining, no country is known to have evacuated the brine from such a cavity and then conducted a decoupled nuclear explosion in it. Air-filled cavities in salt suitable for significant decoupled testing are stable over only a very narrow range of depths from about 200 m to a maximum of 900 to 1300 m. Most areas of thick salt deposits in the Former Soviet Union and the U.S. are typified by efficient transmission for seismic waves and low natural seismic activity. The scaled cavity radius of 20 m cited in the literature for full decoupling in granite is poorly determined, probably is too small, and has resulted in overestimates of the potential to employ cavities in hard rock for decoupled nuclear testing. For cavities in hard rock, lack of any known experience in conducting decoupled nuclear testing in them, insuring containment in the presence of large differences in principal stresses and the presence of joints and other inhomogeneities on a scale of 1 to 100 m, and the excavation of such a large cavity without being detected are factors that make clandestine decoupled testing of a few kt or larger very unlikely for sites in hard rock, even for countries with considerable testing experience. Decoupled testing of large DF in any media at such yields by countries lacking containment experience would be difficult to carry out in secrecy.
Re: Deterrence
Thanks^^^Yes — that Springer chapter backs this up. Large decoupling factors are only feasible in very specific conditions (mainly salt domes), mostly known Soviet-era sites. Hard-rock decoupling at kt-scale is extremely unlikely to be both contained and hidden.
It explicitly says clandestine decoupled tests of a few kt or larger are very unlikely, even for experienced nuclear states, and cavities of that size are themselves detectable.
So claims about “hundreds of tons” being cleanly hidden without seismic/radionuclide evidence don’t line up with the physics or the literature.
Besides - The old DF~50 decoupling numbers only apply to low-frequency waves. Higher-frequency waves like Pn/Lg and short-period energy barely get muffled, so modern seismic arrays can still detect them. Detection isn’t just about single-station magnitude; networked arrays, waveform correlation, and mb vs Ms discrimination make hiding even sub-kiloton explosions extremely hard.
Throw in radionuclide monitoring (xenon isotopes) and any “hidden” test becomes even less plausible. Physics + modern networks basically rule out truly secret decoupled nukes.
(I hav been to Nevada Test Site where almost all US (99%+) nuclear tests were done — fun fact: you can’t really hide a nuke in hard rock. All tests were fully coupled, loud enough for the world to notice!(the U.S. never did “decoupled” nuclear tests there — all underground tests there were fully coupled and detectable. Hard rock geology just isn’t friendly to hiding kt-scale blasts. .. --one or two coupled were test run at other side.. but they were small )
It explicitly says clandestine decoupled tests of a few kt or larger are very unlikely, even for experienced nuclear states, and cavities of that size are themselves detectable.
So claims about “hundreds of tons” being cleanly hidden without seismic/radionuclide evidence don’t line up with the physics or the literature.
Besides - The old DF~50 decoupling numbers only apply to low-frequency waves. Higher-frequency waves like Pn/Lg and short-period energy barely get muffled, so modern seismic arrays can still detect them. Detection isn’t just about single-station magnitude; networked arrays, waveform correlation, and mb vs Ms discrimination make hiding even sub-kiloton explosions extremely hard.
Throw in radionuclide monitoring (xenon isotopes) and any “hidden” test becomes even less plausible. Physics + modern networks basically rule out truly secret decoupled nukes.
(I hav been to Nevada Test Site where almost all US (99%+) nuclear tests were done — fun fact: you can’t really hide a nuke in hard rock. All tests were fully coupled, loud enough for the world to notice!(the U.S. never did “decoupled” nuclear tests there — all underground tests there were fully coupled and detectable. Hard rock geology just isn’t friendly to hiding kt-scale blasts. .. --one or two coupled were test run at other side.. but they were small )
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S_Madhukar
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Re: Deterrence
I would still expect MEA to march up the Chinese ambassador and ask him some pointed questions !
Re: Deterrence
Agreed. That's statecraft and no such opportunity must be lost, especially against our only mortal enemy, China.S_Madhukar wrote: ↑10 Feb 2026 05:25 I would still expect MEA to march up the Chinese ambassador and ask him some pointed questions !
Re: Deterrence
SSridharji et al -SSridhar wrote: ↑10 Feb 2026 07:50Agreed. That's statecraft and no such opportunity must be lost, especially against our only mortal enemy, China.S_Madhukar wrote: ↑10 Feb 2026 05:25 I would still expect MEA to march up the Chinese ambassador and ask him some pointed questions !
Ask them what exactly ???—
That’s not diplomacy, that’s theatre. If India had *any* seismic or radionuclide evidence, this wouldn’t be handled via a silly stunt like MEA scolding; it would go straight into *right* channels and pressure which China will understand.“Did you secretly test a nuke?”
Dragging the ambassador in without proof just tells Beijing we’re reacting to US talking points.( Wild claims - even coming from USA -may be Paki ethos to repeat, not ours). Sometimes silence isn’t weakness — it’s a sign there’s nothing conclusive to escalate and/or that the adults already compared notes.
____
Re: Deterrence
FWIW - Sridharji Adding to ^^^..a Few points -- let me know your thoughts..
- The allegation was publicly made by Thomas G. DiNanno, the U.S. Under Secretary of State for Arms Control and International Security. He made the claim at a UN Conference on Disarmament in Geneva, stating that China had conducted covert nuclear explosive tests in 2020 and used methods like “decoupling” to conceal them.
DiNanno is a career official in arms control. The position exists to speak for U.S. policy on disarmament and verification issues.
However, his allegations were not accompanied by public technical evidence — meaning he asserted the claim without releasing seismic, radionuclide, satellite, or other data to back it up. This makes the claim politically significant ( not scientifically verified )
- How valid are these claims scientifically? (My take - but I believe experts will agree)
-No independent evidence supports the claim:CTBTO) — the global body that monitors nuclear testing via seismic and radionuclide networks — has stated its system did not detect any event consistent with a nuclear weapon test at the time in question. That assessment has not changed after detailed analysis.
- NONE OTHER (I checked a few) showing an unusual explosive event consistent a buried nuclear test around June 22, 2020.
- No independent seismic confirmations
So, IMO, the claim remains unverified pending release of independent signals or data. It is currently a U.S. government policy statement, not a proven event by independent monitoring bodies.
-(U.S. State Department compliance reports in previous years have raised concerns about potential tests /preparation at Lop Nur based but those were suggestive, not definitive, and did not claim China actually detonated a nuclear device.
-China, of course, has strongly denied the allegations, calling them “outright lies” and suggesting the U.S. is using the claim to justify its own potential nuclear testing.
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Indian media are reporting the U.S. allegation (that China conducted a nuclear explosive test in June 2020 (timed near the Galwan clash)- mostly based on U.S. statements.
- But other than that I have not seen anything. Even though India does have excellent remote sensing, seismic, and intelligence resources — and would logically keep an eye at activities at Lop Nur — India does’t comment publicly on these matters unless governments okays it. ( India’s own surveillance didn't pick up such a test in any public statement)
IOW - AFAIK, India’s government hasn’t made any official statement confirming or denying the U.S. claim that China conducted a secret nuclear test in 2020. Indian media are publishing the U.S. allegation and China’s denial, but no MEA or Defence Ministry response has been widely reported. Given the sensitivity of such intelligence topics, that silence doesn’t necessarily mean India disagrees...but...
Also, note that India has publicly responded to some other nuclear testing claims (not related to this China allegation)
(-Trump publicly claimed that Pakistan was secretly testing nuclear weapons in 2025-)
In that case , India’s MEA responded to a U.S. claim about Pakistan’s alleged secret nuclear tests, pointing to Islamabad’s historical proliferation activities and India’s Defence Minister responded to broader U.S. comments about nuclear tests by saying India doesn’t act out of fear of others conducting tests, without directly addressing specific accusations about Pak or China. (If I remember the quote was something like "We noted Trump's quote..without confirming or denying it - in true Chankakya style)
These responses show India is willing to comment on nuclear testing narratives when it chooses to, but there’s no official Indian statement confirming / denying the specific China 2020 test claim so far.)
- The allegation was publicly made by Thomas G. DiNanno, the U.S. Under Secretary of State for Arms Control and International Security. He made the claim at a UN Conference on Disarmament in Geneva, stating that China had conducted covert nuclear explosive tests in 2020 and used methods like “decoupling” to conceal them.
DiNanno is a career official in arms control. The position exists to speak for U.S. policy on disarmament and verification issues.
However, his allegations were not accompanied by public technical evidence — meaning he asserted the claim without releasing seismic, radionuclide, satellite, or other data to back it up. This makes the claim politically significant ( not scientifically verified )
- How valid are these claims scientifically? (My take - but I believe experts will agree)
-No independent evidence supports the claim:CTBTO) — the global body that monitors nuclear testing via seismic and radionuclide networks — has stated its system did not detect any event consistent with a nuclear weapon test at the time in question. That assessment has not changed after detailed analysis.
- NONE OTHER (I checked a few) showing an unusual explosive event consistent a buried nuclear test around June 22, 2020.
- No independent seismic confirmations
So, IMO, the claim remains unverified pending release of independent signals or data. It is currently a U.S. government policy statement, not a proven event by independent monitoring bodies.
-(U.S. State Department compliance reports in previous years have raised concerns about potential tests /preparation at Lop Nur based but those were suggestive, not definitive, and did not claim China actually detonated a nuclear device.
-China, of course, has strongly denied the allegations, calling them “outright lies” and suggesting the U.S. is using the claim to justify its own potential nuclear testing.
---
Indian media are reporting the U.S. allegation (that China conducted a nuclear explosive test in June 2020 (timed near the Galwan clash)- mostly based on U.S. statements.
- But other than that I have not seen anything. Even though India does have excellent remote sensing, seismic, and intelligence resources — and would logically keep an eye at activities at Lop Nur — India does’t comment publicly on these matters unless governments okays it. ( India’s own surveillance didn't pick up such a test in any public statement)
IOW - AFAIK, India’s government hasn’t made any official statement confirming or denying the U.S. claim that China conducted a secret nuclear test in 2020. Indian media are publishing the U.S. allegation and China’s denial, but no MEA or Defence Ministry response has been widely reported. Given the sensitivity of such intelligence topics, that silence doesn’t necessarily mean India disagrees...but...
Also, note that India has publicly responded to some other nuclear testing claims (not related to this China allegation)
(-Trump publicly claimed that Pakistan was secretly testing nuclear weapons in 2025-)
In that case , India’s MEA responded to a U.S. claim about Pakistan’s alleged secret nuclear tests, pointing to Islamabad’s historical proliferation activities and India’s Defence Minister responded to broader U.S. comments about nuclear tests by saying India doesn’t act out of fear of others conducting tests, without directly addressing specific accusations about Pak or China. (If I remember the quote was something like "We noted Trump's quote..without confirming or denying it - in true Chankakya style)
These responses show India is willing to comment on nuclear testing narratives when it chooses to, but there’s no official Indian statement confirming / denying the specific China 2020 test claim so far.)
Re: Deterrence
^^^ possible motive: “ This allegation was part of a broader U.S. effort to pressure China into joining arms control negotiations, especially as the New START treaty between the U.S. and Russia approached expiration.”
Russia was happy to keep the treaty bilateral, and took the stand that if China was to be included, then so should the other nuclear powers. The New Start treaty was extended and expired February 5th, 2026. Which may be why the charges of clandestine nuclear tests are coming up again at this time.
Russia was happy to keep the treaty bilateral, and took the stand that if China was to be included, then so should the other nuclear powers. The New Start treaty was extended and expired February 5th, 2026. Which may be why the charges of clandestine nuclear tests are coming up again at this time.
Re: Deterrence
^^^ Certainly possible.. or Trump being Trump..
Meanwhile ...latest unhinged Truth Social screed, claims that [if Canada makes a trade deal with] China, "the first thing China will do is terminate ALL Ice Hockey being played in Canada, and permanently eliminate The Stanley Cup."
Meanwhile ...latest unhinged Truth Social screed, claims that [if Canada makes a trade deal with] China, "the first thing China will do is terminate ALL Ice Hockey being played in Canada, and permanently eliminate The Stanley Cup."
Re: Deterrence
I dont get it. why is massa going global with START while withdrawing from everywhere else? USA/Russia are still top dogs there by a wide margin!
Re: Deterrence
And, China has a huge number & variety of delivery systems that INF Treaty prevented the US from having.
Re: Deterrence
https://www.armscontrol.org/act/2025-01 ... ll-growing
China’s nuclear arsenal likely exceeds 600 operational nuclear warheads as of mid-2024, part of a diversified buildup that is projected to continue after 2030, the Pentagon said in its annual assessment of China’s military capabilities.
In its annual report on Chinese military power, the Pentagon assesses that Beijing has completed one of its two fast breeder reactors at Xiapu to support the country’s expanding nuclear arsenal. (Satellite image by Maxar Technologies and Google Earth)In its annual report on Chinese military power, the Pentagon assesses that Beijing has completed one of its two fast breeder reactors at Xiapu to support the country’s expanding nuclear arsenal. (Satellite image by Maxar Technologies and Google Earth)
When compared to previous reports, “[w]e’re showing a rate of growth that is pretty well consistent with what we’ve described in reports over the past three years…about their nuclear expansion and modernization,” a senior U.S. defense official said at a press briefing on Dec. 18.
The spokesperson for the Chinese Defense Ministry, Zhang Xiaogang, told state-run Xinhua news on Dec. 21 that the intention of China’s nuclear weapons development is to “safeguard the country’s strategic security.”
“We urge the [United States] to stop fabricating false narratives, rectify the erroneous perception of China, and push for the healthy, stable development of bilateral and military relations,” he said.
The Pentagon’s annual report on China’s military power, published Dec. 18, covers developments through 2023. It repeats an estimate first made in 2021 that “China will have over 1,000 operational nuclear warheads by 2030” and will “continue growing its force through at least 2035.” But the report did not reiterate the projection published in 2023 that China aims to obtain 1,500 warheads by 2035.
Re: Deterrence
Can you expand on this?
From what I know (and looking it up for current status)
- The INF band (500 km – 5,500 km, Ground-launched ballistic and cruise missiles only):
- 500–700 (Open source) Chinese missiles in the INF-prohibited range category. Per US majority of China’s ballistic missile force falls within this band. and that’s the crux of the “INF asymmetry” argument.
- INF Treaty (1987) constrained the U.S. (and USSR/Russia), but not China, The U.S. and USSR eliminated entire categories of land-based missiles, while China kept building it up.
-In 2019, the U.S. formally withdrew from INF. (U.S. has begun developing ground-launched intermediate systems again.vBut they are not yet deployed in large numbers.)
- INF did not prevent the U.S. from having nuclear capability in Asia. ( only not having ground-based intermediate-range missiles always had SLBMs, ICBMs, Bombers etc..).
(So US says something like "Why should we remain constrained when China has built hundreds of these systems".
Re: Deterrence
Just finished reading this book:
https://en.wikipedia.org/wiki/Nuclear_War:_A_Scenario
For those who have an interest in these matters, a lot of the stuff in there will not be new. However even I was struck and horrified by the speed at which the events start unfolding. Launch on warning policies meant that the whole exchange gets over in 72 mins from the moment the first missile is detected towards US to all out attack by US with everything in its arsenal.
As Khrushchev said and is quoted in the book: “The living shall envy the dead”.
Its not a reference book but is written with enough research and backed up with references and interviews that it is not incorrect in its descriptions.
For those of lesser morals, it is available if you sail the bay with skull flag…
https://en.wikipedia.org/wiki/Nuclear_War:_A_Scenario
For those who have an interest in these matters, a lot of the stuff in there will not be new. However even I was struck and horrified by the speed at which the events start unfolding. Launch on warning policies meant that the whole exchange gets over in 72 mins from the moment the first missile is detected towards US to all out attack by US with everything in its arsenal.
As Khrushchev said and is quoted in the book: “The living shall envy the dead”.
Its not a reference book but is written with enough research and backed up with references and interviews that it is not incorrect in its descriptions.
For those of lesser morals, it is available if you sail the bay with skull flag…
Re: Deterrence
Isnt INF treaty dead? Are we saying USA has no appetite to develop such missiles as that would also mean warhead development and hence wants START including China?