Arms Control Wonk

The most rewarding aspect of the Monterey Institute is the students.  Okay, it’s the weather.  But the students are a close second.

We have, for instance, an embarrassment of Chinese-speaking graduate students.  One of our best, Jonathan Ray, has been staring at Chinese social media sites.  While most young Chinese men largely surf for smut, Jonathan has discovered titillating images of the sort familiar to readers of this site: wonkporn!

Over the past few months, images of at least three new Chinese transporter-erector-launchers have appeared on various Chinese social media sites.  Here is our best effort at beginning to sort through them.  Consider this a first cut. What we really need to do now is to start modeling the canisters to work out what sort of missiles might be inside.

Show and TEL

Jeffrey Lewis and Jonathan Ray

1.

Second Artillery Transporter-Erector-Launchers in Chinese Social Media

Over the past year and a half, Chinese bloggers have posted images of at least three new-style transporter-erector-launchers (TELs) and their respective missile canisters.  These images depict (1) a TEL with at least six axles, (2) a 6-axle TEL, and (3) an 8-axle TEL.

Since 2009, China has steadily replaced the old-style TELs for its DF-15 and DF-21 ballistic missiles with new-style TELs produced by the Wanshan Special Vehicle (WSV) Company.  WSV-produced TELs are clearly different in style from previous Chinese TELs and resemble those manufactured by MAZ/MZKT in Belarus, with whom Wanshan established a joint-venture company.  The TELs are similar in style to those that North Korea has displayed for its Musudan intermediate-range ballistic missile (IRBM) and new KN-08 ICBM.  (WSV appears to have produced the TEL for the KN-08.)

The photographs posted by Chinese bloggers appear to show three more new-style TELs that are clearly larger than known TELs for the DF-11, DF-15 or DF-21. The angles on the photographs are poor and in some cases key features are obscured, either deliberately or through hasty photography.

With these cautions in mind, our preliminary assessment is that these TELs are for three different missiles, including the DF-31/DF-31A.  Other possibilities include a new MRBM or IRBM, a new ICBM under development, or China’s SC-19 exo-atmospheric interceptor.  More definitive conclusions require estimates of canister size and the maximum loading of the TELs.

2.

At Least 6-Axle TEL

On November 3, 2011, Weibo (Chinese Twitter) user “Richard潇” posted the a picture of a TEL with at least six axles. (Four wheels are visible, with two wheels obstructed by the photographer’s hand.) The TEL’s wheel-configuration is similar to a TEL that appeared in Pyongyang in 2010 carrying the Musudan intermediate-range ballistic missile (IRBM). Although the chassis appears similar, the image taken in China shows a TEL with a canister and a different erector.

The original picture and post are no longer on “Richard潇”’s Weibo account, but a copy is available on his BBS blog:

The text reads: “Hanchuan, accidentally encountered a missile [s: very formidable].”  (The “s:” appears to be a Chinese emoticon to express awe.)

Hanchuan (汉川) is a county-level city in Xiaogan (孝感), Hubei Province. The Wanshan Special Vehicle Company’s factory is located in Xiaogan, Hubei Province.

3.

6-Axle TEL

 On February 17^th, two bloggers posted pictures of a six-axle TEL, claiming it is a DF-25 IRBM. The bloggers reposted the image from an automobile news site.  One of the two bloggers claims that the photographer was on vacation in Xinyi City in Xuzhou (新沂市, 徐州), Jiangsu Province. There are no reported Second Artillery bases within 200 kilometers of Xinyi City.  The image may show either a new IRBM deployed at an unreported launch brigade or in transit from the Nanjing Guided Missile plant 200 kilometers to the south.

4.

8-Axle TEL

On February 8^th Xilu.com, a Chinese military news site, posted what looks like an eight-axle TEL, but with the cargo cropped out. The image was titled – “The Second Artillery’s Newest Dongfeng Exposed; The chassis that an internet user photographed is a model number never seen before” (“二炮最新东风导弹曝光网友拍摄底盘是从未见过的型号”) – but not accompanied by any explanatory text. Chinese bloggers were disappointed but not surprised.

Then on March 6, Sina Military Forum user “Red Arrow 73 (红箭73)” posted a different and complete picture of a similar (possibly even the same) eight-axle TEL carrying what he claims is a DF-31.

There are no geographic data about the location of this TEL.

This is the largest TEL spotted in China to date. In 2010, the Department of Defense said, “China may also be developing a new road- mobile ICBM, possibly capable of carrying a multiple independently targeted re-entry vehicles (MIRV).”

Fewer than 10 bloggers have reposted the picture, and have speculated the missile is a DF-41 and that the design is similar design to the Russian Topol-M. In 2012, one press report in the U.S. claimed the Second Artillery conducted a “DF-41” flight test although the report is not independently confirmed. One thread on a Chinese blog describes the TEL’s missile as “又粗又长,” which translates as “both rough and long.”  The conversation soon degraded; it is not safe for work if your boss speaks Chinese.

A similar 8-axle WSV-manufactured TEL appeared in North Korea’s 2012 military parade carrying the KN-08 ICBM. As in the case of the Musudan, however, despite a similar chassis, the TEL in China carries a canister and has a different erector. Shipping documents obtained by Asahi and published by James Hardy for Jane’s, as well as a press release posted on the WSV website, suggest that WSV manufactured the TELs seen carrying the KN-08.

5.

China’s Ongoing TEL Upgrades

While these three TELs are of different sizes, they all appear to be WSV-manufactured and, at least in style, resemble MAZ models. In the 2009 National Day Parade, China paraded DF-15 and DF-21 with new WSV-style TELs that replaced older towed configurations.

For example, here are before and after images of the DF-15:

Here are “before” and “after” images of the DF-21:

The 2009 parade also included a DF-11A, which was carried on a WSV-style TEL. (The DF-11 appears to be the first Chinese missile that received a WSV-style TEL dating to at least 1999.)

China displayed the DF-31A, however, with an old-style towed erector-launcher (sometimes called a MEL or Mobile Erector Launcher).

For some time, observers have wondered when China’s road-mobile ICBM force would receive new vehicles.

We now have images of what appear to be three new TELs, one or more of which is apparently for the DF-31 series.

(1) The smallest appears to have six axles.  This TEL is larger than the TEL for the DF-21 medium-range ballistic missile (MRBM), which has five axles, and may correspond to a new MRBM or IRBM.

(2) It is unclear how many axles the next largest TEL has, but the wheel configuration indicates six or more and a different chassis from the 6-axle TEL.  It is possible that this is either a DF-31 or DF-31A TEL.  The old DF-31 TEL had eight axles, but in a towed configuration.

(3) Finally, the 8-axle TEL is the largest seen to date in China. It is presumably for China’s longest-range mobile ICBM, either a DF-31A or the reported DF-41.

One possibility is that the three TELs are for the DF-31, DF-31A and the reported DF-41.  Another possibility is that the TELs are for an unreported IRBM, the DF-31 and either the DF-31A or a reported DF-41.  A third possibility is that one of the TELs is associated with China’s SC-19 hit-to-kill interceptor.

Further constraining the possibilities requires modeling the TELs and canisters in an effort to gauge the canister size and maximum load to provide a preliminary assessment of the missiles carried inside.

WSV TELs in China
Diagram	Picture	Missile	WSV Model	Axles	Load Capacity (1000 kg)
		DF-11	WS2400	4	22.0
		DF-15	WS2400	4	22.0
		DF-21	WS2500 or WS2600	5	35.5 or 42.5
		??	WS2900	>6	55.0
		??	WS2900	6	55.0
		??	Modified WS2900?	8	Up to 90.0
Diagrams depict the TEL wheel configuration. They are not drawn to scale and are for illustrative purposes only. All Wanshan Special Vehicle (WSV) model information, unless indicated otherwise, is based on the “Sanjiang-Volat Special Vehicle Company” brochure, excerpts of which are available on the FYJS blog. Sanjiang-Volat is a joint enterprise between CASIC’s Sanjiang Space Wanshan Special Vehicle Company and Belarus’s Minsk Wheel Tractor Plant, and produces the WS (Chinese) and M3KT (Belarusian) series of all-terrain vehicle chassis. An eight-axle chassis is not commercially available, but the WSV website claims that the WS series can carry loads up to 90,000 kg.

Last month, David Albright published screen shots of a solicitation by an Iranian company for ring magnets that may suitable for centrifuge bearings – a crucial component of Iran’s centrifuges. The question is whether the magnets, which fall below the thresholds established in the NSG “trigger list” are really suitable for Iran’s IR-1 centrifuges or not.

Ferenc Dalnoki-Veress and I have written an analysis comparing the strength of the magnets sought with an effort by Pakistan to produce P2 centrifuges in Germany in 1991.  Our conclusion is that, at least on the issue of magnet strength, the magnets are consistent with a first generation centrifuge like the IR-1.

You can find our reasoning below the jump.

How Many Mega Gauss Oersteds Does It Take to Make Your World Spin?

Ferenc Dalnoki-Veress and Jeffrey Lewis

March 20, 2013

Accusing a foreign individual, entity or government of engaging in illicit commerce relating to the spread of nuclear weapons is a complex issue and must be handled carefully. Ideally, the item in question must match to the known specification of the nuclear-use item. However, buyers often purchase items that don’t precisely match these specifications to circumvent export control regulations. To prevent the sale of these items, the NSG has a “catch-all” provision under which members agree to refrain from exporting even non-controlled goods if there is a reason to believe that it is intended for a nuclear weapons program.

The recent case of an Iranian firm soliciting an order of ring magnets illustrates some of the challenges in controlling dual-use technologies.

Last month, David Albright published a report on the Institute for Science and International Security website suggesting that Iran attempted to purchase 100,000 ring magnets suitable for centrifuge bearings – a crucial component of Iran’s centrifuges (Ring Magnets for IR-1 Centrifuges, February 13, 2013).  Albright posted a screenshot (Figure 3) showing a web inquiry on a Chinese website by Mr. Mohammad Tahmouresi , representing an Iranian trading company called Jahan Tech Rooyan Pars Co., regarding 100,000 ferrite barium strontium ring magnets.  (In 2012, Canada sanctioned Jahan Tech Rooyan Pars Co. for supporting Iran’s “proliferation sensitive” activities.)  Albright also provided a translation of the inquiry, which included some text in Chinese (Figure 4).  Albright, working with an unnamed European government and an ISIS centrifuge expert, concluded that the technical specifications of the ring magnets generally matched those for Iran’s first-generation centrifuges, requiring only minor modifications to the bearing. Albright, citing concerns about proliferation-sensitive information, redacted the dimensions and other technical information that would allow outside experts to assess his conclusions.

Upon closer inspection, however, Albright inadvertently left in a key technical detail relating to the strength of the magnet – that Iran was seeking magnets with a strength (in terms of BHmax) is 3 MGOe. BHmax is an important parameter because the magnet must stabilize the rotor as it spins at hundreds of meters per second. The threshold for controlling magnet exports set by the Nuclear Suppliers Group is much higher than this – 10 mGOe – leading some commentators to question Albright’s assessment.  It is important to note that the thresholds established by the Nuclear Suppliers Group are reached by negotiation and attempt to balance competing interests in restricting the spread of sensitive technologies and permitting normal commerce. This is especially challenging when dealing with technologies, like the IR-1 centrifuge, that are more than thirty years old. Whether this inquiry is plausibly linked to Iran’s centrifuge program depends in part on the possibility that the IR-1 uses ring magnets that fall below the threshold specified by the NSG. If such magnets are unsuitable for Iran’s centrifuges, then we can dismiss the allegation.

As it turns out, we have relatively detailed information about the ring magnets used in Pakistan’s P2 centrifuge because of a failed 1991 effort by Pakistan to purchase similar ring magnets in Germany.  In 1995, Mark Hibbs reported that Pakistan attempted to purchase similar ring magnets from the German firm Magnetfabrik Bonn (MFB) GmbH (see: M. Hibbs, “Siemens Venture Believed Used in Pakistan Centrifuge Quest,” Nuclear Fuel, Aug. 28, 1995).  Hibbs did not report the strength of the magnets, but he did state that Pakistan ordered aluminum-nickel-cobalt (Alnico)-260 S-ring magnets. The numerical suffix “260” is a designation specifically corresponding to the German standard for the technical conditions of materials of permanent magnets (DIN 17410) and corresponds to a (BH)max=18 kJ/m3 or 2.4 MGOe. In correspondence with Hibbs, we were able to confirm that the original specification of the 1991 procurement effort was 18 kJ/m3.

Our conclusion is that, at least on the issue of magnet strength, the magnets are consistent with a first generation centrifuge like the IR-1.

Hibbs also provided a detailed description of the dimensions of the ring magnets:

“Pakistan had first indicated that Telephone Industries sought magnets sized at 52 millimeters in diameter and 8 mm in height, with a ring thickness of 36 mm. It later specified a precise diameter of 52.8 mm and a thickness of 36.8 mm and defined fine tolerance requirements in the range of a few hundredths of millimeters.”

The same dimensions are given in an ISIS report by Albight, Brannan and Stricker. “For example, a P2 ring magnet sought by Iran later has dimensions of 52.8 mm x 36.8 mm x 8mm. P1 ring magnets have similar dimensions.”

It is, of course, possible that the magnets were intended for other purposes. However, we have concluded that from the point of view of the magnetic properties they can also be used for ring magnets for older generation IR-1 centrifuges, which the IAEA has reported Iran still uses in their centrifuge facilities.  This is an important data point that characterizes the item in question as being appropriate for nuclear-use.  Knowing the dimensions of the attempted procurement would shed further light on the issue.

An unanswered question relates to the Canadian sanctions against Jahan Tech Rooyan Pars.  Although Canada stated that the sanctions are the result of Jahan Tech Rooyan Pars having provided “support” to proliferation-sensitive activities in Iran, Canada has not made public a specific allegation about what firm might have done to elicit sanctions.. Further information from the Canadian government could help understand the final end-user for any ring magnets purchased by Jahan Tech Rooyan Pars.

I have a column up at Foreign Policy (“Billion Dollar Baby”) on the announcement by newly installed SECDEF Chuck Hagel that 14 additional ground-based interceptors ought to do it with regard to North Korea.  I noted in the piece that the focus on North Korea led to a comparative neglect of the decision to cancel Phase 4 of the European Phased Adaptive Approach intended to provide an early shot at an Iranian ICBM. (Not everyone ignored it, of course, but most of the major daily papers did.)

After I submitted my column, the Washington Post wrote a strange (even by its standards) op-ed lamenting the loss of Phase 4, explaining:

In doing so, the administration has eliminated the possibility of a defensive system that would give the United States two shots at an Iranian ICBM — what in Pentagon jargon is called a shoot-look-shoot capacity. [sic]

Actually, no.  This is pretty much all wrong.

Let’s just observe that, as a factual matter, the earth is round.  As a consequence, the interceptors based in Alaska (near the north pole) do have a chance (in hell) of intercepting an Iranian missile.  The current doctrine is to salvo-fire five interceptors at each target.  That is five shots, not two.  The reference to shoot-look-shoot, which seems like plain English to me, refers to the ability to shoot at the incoming missile, then look to see whether the first shot killed the missile before expending a shot again.  Shoot.  Look.  Shoot (if necessary).  The improvement in efficiency is obvious, but what that takes is time — sweet, precious time.

(I should also mention the two slightly different definitions of shoot-look-shoot.  In the second version, you fire additional interceptors if the first shot gets close enough and sees more than one credible target.  We don’t configure the kill vehicles that way, but we could.)

First, Phase IV of the EPAA might not have provided a shoot-look-shoot capability.  The report of the National Academies is a little coy about this, because I think the situation is pretty borderline and delves into the classified realm.  The basic problem is the Alaska is far enough away on a curving earth that the window to shoot at incoming Iranian ICBM is pretty narrow — probably right around the apogee.

I would encourage the collective you to make some formal models, but I suspect the answer will depend very much on the assumptions in the model — assumptions that are hard to make given the fact that neither the SM-3 IIB nor the notional Iranian ICBM yet exist.  The uncertainty is probably enough, however, to discourage heavy investment in Phase 4 for the purpose of gaining a shoot-look-shoot capability, especially given the alternatives.  (Choices are always about the alternatives.)

I make the apogee something like 6,000-7,000 km from the Fort Greely site. (I note the test range maxes out at 8,000 km, which I suspect probably bounds the worst-case Iranian engagement for it.)  That’s a long, long way for an interceptor to travel, which means that the interceptor is looking at well in excess of 10 minutes of flight time, maybe even in excess of 15 minutes. If the engagement window from Alaska is around 1,800 secs into the flight, then the interceptor might need to be launched as early as 800 seconds after the Iranian launch.  One might be able to fit in a full engagement cycle in the first 800 seconds, but I think it’s pretty close.

The tight kinematics mean that it would not be responsible to rely on Phase 4 of the EPAA for a shoot-look-shoot capability if there are better options.

Then there are the other criticisms leveled by the National Academies:

(1) Phase 4 is not necessary for European defense (and therefore need not be “in” Europe), (2) that the rationale of an “early” intercept as a solution to the midcourse discrimination problem is an illusion, (3)  that Iran might overfly the site in Poland, (4) that the National Academies concluded the interceptor likely couldn’t achieve 5 km/s in the VLS launcher volume, and (5) that an East Coast site with a new interceptor, new radars and new concept of operations would be much, much better.

The editors at the Washington Post simply skip over all this, as well as the fact that the Administration is starting the EIS process for an East Coast site (under Congressional duress).  As I have noted before, an East Coast site is a terrible idea unless it is a packaged with the other changes recommended by the National Academies.  If the editors of the Washington Post took ten minutes to think through this, they might have written an op-ed usefully advocating for the broader set of recommendations in the National Academies report.

Instead, I get the feeling that they wrote the editorial as a sop to certain Republican politicians.  ”See, we can be critical of the Administration!”   One of my complaints about editorials in general, but also bipartisanship, is that we tend to compromise on outcomes in ways that have no inherent strategic logic.  So, for example, if the President says he will end nuclear testing and some opponent calls for seven tests next year, the Post might write in favor 3 1/2 nuclear tests — a nonsense solution that achieves nothing other than standing in the middle.

Rather than compromising on outcomes, what we ought to do is try to make policies that address the concerns expressed by the other side of the argument. I realize that can hard to do when much of official Republican foreign policy boils down to “I hate the President and his works,” but there are certainly conservatives who speak in complete sentences and chew with mouths closed.  (Even if they eat babies. Kidding!)

What the Post might have done is observe that conservatives are not wrong to assert that we have a real (if still emerging) challenge from North Korean and Iranian missiles.  In that context, one might certainly explore the best architecture to meet that challenge, without breaking the bank. I still think back to a conversation I had when I was a young RA at CSIS, with someone who would not mind one bit being described as a “neoconservative Star Wars fanatic.”

He told me he was opposed to space-based defenses.  I was stunned.

“It’s simple.  I want missile defense to work.”

Liked him ever since.

Megan Garcia has penned a great little essay on “emerging powers” in nuclear politics in general, and Brazil in particular.  Let me also plug her monograph, Global Swing States and the Non-Proliferation Order.

The subject is super important — one of the big ideas lurking in the back of my head concerns how the nonproliferation regime adjusts to the spread of manufacturing technologies.  Americans like to list all the stuff that newly industrialized countries like Brazil must do to fully embrace nonproliferation, such as signing and ratifying the Additional Protocol.  What Americans don’t like talking about is what we have to do in exchange — accepting that Brazil’s participation confers the right to help draft the rules.  That’s probably the main reason I remain appalled at how the Obama Administration handled the May 2010 Zombie Fuel Swap with Iran.

Anyway, that’s my blog post.  Megan’s post puts Brazil’s embrace of nonproliferation in some historical context, closing with a look at where the country’s domestic politics are today:

There has been a lot of buzz lately about what you might call ‘rising powers’ or ‘emerging powers’ or ‘the countries that seem to know how to have a lot of fun and also eat excellent food.’  Let me draw your mind from Turkish meze and Indian samosas to the role these countries are playing in nuclear politics.

Take Brazil, for example.

Although it’s slowed over the pew few years, Brazil’s economic growth is still giving China a run for its money (literally). The average rent for an apartment in Rio is somewhere around $2,000 a month, for goodness sake. And, to the chagrin of their neighbors, Brazilian leaders have had their eye on the coveted Global Leader moniker for quite some time; first via Lula’s fiery presence on the world stage and now with Rousseff’s quiet determination to keep economic development on course.

Brazil’s engagement with the global nuclear regime has been a complex one. Initially, Brazilian leaders didn’t want to join the Non Proliferation Treaty, and viewed it as discriminatory because it forced less developed nations into accepting permanent technological disadvantage. In the 1950’s Brazil negotiated with West Germany to buy three centrifuges but the U.S. and British occupation authorities blocked the deal. Under the Filho Administration in the 1950’s the U.S. normalized relations and sent research reactors to Brazil under the Atoms for Peace program.

Between 1964 and 1985 Brazil was governed by a military dictatorship that both acquired its own nuclear technology capacity and relied on technological assistance from the United States because of energy shortages and the 1973 oil shocks. Because the U.S. was unwilling to transfer the nuclear fuel cycle in its entirely to Brazil, the Brazilian government secretly negotiated with West Germany for nuclear power reactors, uranium processing facilities, conversion, enrichment and reprocessing technology. By the time the military regime ended in 1985 Brazil’s Navy had an indigenous program to develop a naval reactor, the Army was developing a large graphite-moderated reactor to create weapons usable plutonium and the Air Force had a program to develop laser enrichment and breeder reactors.

With the fall of the military regime and the emergence of democratic governance in Brazil, the country has emphasized the peaceful nature of its nuclear activities. Its 1988 constitution bans any use of nuclear weapons—a major step for a country that had been developing the capabilities that would allow it to develop a weapon if it chose to. Brazilian President Fernando Collor de Mello also sealed Brazil’s underground atomic test site in 1990, in part to improve relations with the U.S. (He snuck that move in before being impeached.) And in 1998 Brazil completed its accession to the NPT, despite heated internal debate about whether acceding to a treaty that many experts believed to be inherently unfair was worth becoming integrated into the global nonproliferation regime. (The internationalists won that argument.) Brazil also ratified the Comprehensive Test Ban Treaty in 1998.

Brazil has been a stalwart champion of generating regional solutions to nuclear security problems. In 1991, after years of seeing each other as nuclear rivals, Brazil and Argentina created the Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials (ABACC) to monitor each other’s nuclear activities and facilities and ensure that they were exclusively for peaceful use. While the IAEA and established powers believe that IAEA inspections go further than ABACC inspections, Brazil maintains that the system provides the highest guarantee of nuclear safeguards.

Which brings us back to today and Dilma Rousseff’s presidency. The question among many of the Brazilian colleagues I’ve spoken to is whether and how Brazil will engage on nuclear issues in the future, both directly with the P5 and in forums like the Nuclear Suppliers Group.

The best thinking that I’d heard from those inside and outside the Brazilian government is that Lula and the Brazilian governing elite learned a lesson from the deal Lula and Turkish Prime Minister Erdogan tried to make with Iran in May 2010. In essence, Lula and Erdogan stuck their necks out to encourage Iran to agree to a fuel swap proposal that they thought was backed by the P5.  The permanent members reacted coldly to the deal negotiated by Brazil and Turkey, catching them off guard. Lula and Erdogan expected their role as mediators to be heralded and instead they got a public lashing. Heavily criticized by the Brazilian domestic press, Lula was lambasted at home as a pawn of the major powers.

In light of Obama’s earlier encouragement of Turkey and Brazil’s role in discussions with Iran, Lula and other Brazilian policymakers publicly and privately fumed when the permanent members of the UNSC disavowed the deal, saying things like, “the traditional centers of power will not share gladly their privileged status.” In the end, the UNSC adopted new sanctions against Iran, effectively taking the agreement negotiated by Brazil and Turkey off the table.  The deal — and the subsequent Brazilian and Turkish decision to vote against UNSC sanctions — sent ripples through the established powers. Brazil and Turkey seemed to demonstrate that they could have an occasional seat at the negotiating table.  Whether they want the seat given what happened in 2010 remains unclear.

Dilma is a much less public president than Lula was. She’s more of a Meryl Streep to Lula’s Charlie Sheen. Rousseff is more focused on domestic economic policy than public diplomacy. This seems to be in part because Brazil’s economic growth has slowed, and in part because of her background in energy and economic issues. With Rousseff’s less public persona than Lula, her penchant for focusing on Brazil’s economy, and the specter of the Iran fuel swap deal lurking in the background, it’s unlikely that she will attempt to mediate between problematic countries like Iran and nuclear weapons states. Whether Brazilian diplomats will mediate in a much less public fashion has yet to be determined.

Several of my colleagues have been scratching their heads over a bizarre story that appeared in the Joongang Ilbo (“U.S. nukes to remain in South, To deter a North attack, weapons to stay after joint drills, possibly on sub”) that attributed a number of odd statements about U.S. nuclear weapons to a “high-ranking South Korean government official.”

Maybe Madame Park likes to drink?

I am not sure I have any special insight into WTF this official is talking about, but here is some text to accompany the sounds of itching skulls.

Let’s start with the oddest statements from the story — emphasis mine throughout — and then I’ll make some observations in no particular order.

After two Korea-U.S. joint military drills end, American vessels equipped with nuclear weapons will stay in South Korean waters to fully guarantee the U.S. “nuclear umbrella” in case North Korea attacks.

A high-ranking South Korean government official told the JoongAng Ilbo yesterday, “If North Korea makes a nuclear attack, retaliation can come from U.S. nuclear weapons stationed in Okinawa or Guam. But considering the time that might take, we need to have a nuclear weapon near the Korean Peninsula.

“By not withdrawing U.S. weapons participating in the Korea-U.S. military exercises, we decided to let them stay a while and see what happens in North Korea,” he said.

…

“We decided to convene another Korea-U.S. submarine drill after the Foal Eagle training ends at the end of April,” the official told the JoongAng Ilbo. “We are still negotiating [with Washington] how to utilize the nuclear weapons after then.”

The official did not specify which warships would remain behind with nuclear weapons.

Sources in the South Korean military told the JoongAng Ilbo that a nuclear-armed submarine is a strong candidate.

“Since the third nuclear test by North Korea in February, there have been calls for us to possess anuclear weapon,” a South Korean military official said. “Among various options – our own development, adoption of tactical nuclear weapons and utilizing the U.S. nuclear umbrella – the third is the most realistic.”

OK, let’s start.

First, I think the South Korean official is attempting to convey that a US nuclear submarine of one sort or another is participating in the ongoing Foal Eagle/Key Resolve exercises.  Now, is this submarine nuclear-armed or nuclear-capable?  The wording “equipped with nuclear weapons” is unambiguous, but perhaps something got lost in the translation.

1. It is possible that exercise includes a nuclear-armed ballistic missile submarine (SSBN). The United States does, in fact, have nuclear-armed ballistic missile submarines participate in exercises, although I have not heard of one participating in a multinational exercise.  There has been some chatter about resuming port calls of nuclear-armed SSBNs in South Korea, something that happened in the late 1970s and early 1980s when extended deterrence was rocky. (Pictured above, maybe, according to Hans.)  Maybe this is a step in that direction.

2. It is also possible that the exercise includes a converted ballistic missile submarine that does not carry nuclear weapons. The USS Ohio, a nuclear ballistic missile submarine the Navy converted to a carry conventional guided missiles, participated in Key Resolve/Foal Eagle 2009.  The South Koreans enjoyed using it as a press backdrop. While an SSGN is not nuclear-armed, it is indistinguishable from the real article to my eye.  The confusion is understandable and, in fact, might be a benefit.

3.  Finally, it is possible that a Los Angeles-class attack submarine, like the USS Bremerton, is participating. Some Los Angeles-class attack submarines, including the USS Bremerton, can carry the TLAM/N — the nuclear-armed Tomahawk.  The United States has not deployed TLAM/N on any attack submarines since early 1992, following the September 1991 President’s Nuclear Initiative. The airframes and warheads have been in storage. The Navy did not plan a replacement system, leaving the Obama Administration to allow the retirement of the TLAM/N to proceed without replacement. In April 2010, Jim Miller testified that the timeline for the retirement of the TLAM/N was over the “next two to three years.” I would be surprised if there were any residual TLAM/N capability at this point, but I can’t rule it out and the South Koreans may simply be none the wiser.

We might get additional clarity over the next few weeks. When a submarine returns home, there is often a little item in the local press that contains some operational information. Maybe some sailor will be indiscreet on a message board.

Second, the whole idea that U.S. nuclear weapons need to be stationed in “Korean waters” is ridiculous.

1. As far as I know, there are no nuclear weapons stationed in Okinawa or Guam, nor any facilities to accommodate nuclear weapons. The Administration does talk about the ability to forward-deploy B-2 bombers to Guam as a symbol of extended deterrence, but I think this is a silly symbol. As I have noted before, ”Nor would the United States forward deploy nuclear-armed B-2s, either in Guam or elsewhere. The B-2 can reach targets from North Korea to Iran directly from Missouri, which is what the United States did in the early stages of operations against Yugoslavia, Afghanistan and Iraq. The only rationale for forward-basing is to permit more sorties – something of interest only in ongoing conventional operations.” Nuclear death and destruction visited upon North Korea will probably come with a 65336 postal code.

2. The flight-time argument is impenetrable to me. Setting aside what difference minutes or hours might make in various nuclear-use scenarios, the flight time for a nuclear-armed ballistic missile is minutes. Putting an SSBN closer to Korea isn’t really necessary and is, in fact, undesirable for any number of reasons. As for the TLAM/N, among the undesirable properties that persuaded the Navy to part with that system, one drawback is the relatively long flight time to target, which is to say nothing of the tendency to crash en route. There just is not, as far as I can tell, any military reason to have a nuclear-armed ballistic missile submarine leave its Pacific patrol grounds to hang out around Dokdo.

Third, and finally, this episode illustrates my pet peeve about extended deterrence.  We don’t do ourselves any favors by attempting to reassure our allies with false promises.  The effort to reassure South Korea through our ability to forward deploy B-2 bombers in Guam — something we wouldn’t do for nuclear-use scenarios — simply reinforces misconceptions that exist in Seoul about the nature of  extended deterrence.  The whole Guam nonsense leaves unaddressed the inaccurate belief on the part of many South Koreans that extended deterrence functions better if there are weapons “close by.”

These misconceptions hamper relations — now we have to turn down a South Korean request to keep a nuclear-armed submarine lurking in the East Sea/Sea of Japan — and over time will undermine the credibility of our commitment.  I have been hopeful that new mechanisms like the Extended Deterrence Policy Committee might allow consultations to reduce our tendency to use obsolete hardware as a symbol of our commitment.

That might still happen, but its clear we aren’t there yet.

A friend and colleague who for some reason wishes to remain nameless offers some thoughts on the uses and abuses of unmanned aerial vehicles. -Jeffrey

If we’ve learned anything from Sen. Rand Paul’s Senate-floor soliloquy, it’s that equal parts bluster and bladder are the makings of modern cultural heroism.

Actually, we’ve learned that the Obama Administration doesn’t plan to kill Americans at random on the street. Jane Fonda, don’t sweat the Hellfire missiles. Who knew?

As for you, Green Card holders, you are on your own. I am sorry.

Meanwhile, the story has emerged in New York Times of how the Administration decided it could whack a blogger who happened not to be on home soil. Tough call, because, you know, citizenship and stuff.

(As it says in Sen. Paul’s beloved Fifth Amendment, “No person shall be deprived of life, liberty, or property, without due process of law, besides a foreigner, who doubtless has it coming.”)

To make a long story short — you don’t think I actually read this stuff, do you? — the deliberative process did not involve some irregular scheme in which an Administration lawyer like Attorney General Eric Holder dashes off a snotty little note to Capitol Hill’s current speechifyin’ champeen. No, no, no. Goodness me, no! It involved two Administration lawyers swapping drafts of a memo, which no one else is allowed to read.

Well, I know what you are going to say. Wasn’t there supposed to be something over and above even that? Funny you ask. Art. I of the U.S. Constitution provides for a body that, faced with novel or ambiguous circumstances — law enforcement? warfare? floor wax? dessert topping? — has the power to address them. This “Congress,” or the “legislative branch,” as it is also known, once was accustomed to making “legislation” concerning, inter alia, the “common defense and general welfare of the United States.” But that may have been before its members discovered the advantages of focusing more on creative forms of blackmail. Olden times.

Someday, perhaps, Sen. Paul and his ilk will see fit to resume their former practices, and we’ll have our “checks” and “balances” back. Or, if that’s too much like work, they could make some more 13-hour speeches instead. If it’s ever necessary to get the Attorney General to say what the law is, I know just the man for the job.

Jeffrey adds: There’s a free tutorial online.

Yeah, so I missed a couple of Ward Wilson Wednesdays. Suck it.

Ward’s final contribution contains an elaborated version of my favorite joke about the epistemology of deterrence.  Like the others, it’s an enjoyable read.  It’s been a pleasure hosting Ward these past few weeks. In case you missed them, here are links to parts 1, 2, and 3.  And remember, Five Myths About Nuclear Weapons is available at a fine bookstore near you.

Enjoy!

Doubts About Nuclear Deterrence, Part IV: The Squirrel Man
by Ward Wilson

So I ran into a guy on a street corner in New York. He was dressed a little strangely and he was whirling something over his head. I looked closer and it looked like he had a dead squirrel that he’d spray painted bright, day-glo pink. Holding it by the tail whirling it like a lasso. You see all kinds of things in New York and I didn’t think anything of it, but there was a tourist from England standing nearby and he accosted the squirrel man. “I say old chap, what is it that you’re doing there?”

Squirrel man says, “I’m whirling a squirrel over my head.” (Like: what’s it to you?)

Englishman: “Yes, yes, I see that. I see that very plainly. But why are you twirling a squirrel over your head, my good man?”

Squirrel man: (patiently) “To keep away the elephants.”

Englishman: (obviously–but still politely–incredulous) “Elephants?”

Squirrel man: (tired of this conversation) “Yep.”

Englishman: “I say, you do know that there are no elephants within four thousand miles of this place?”

Squirrel man: (knowingly) “Yep. It works.”

This is a deterrence joke. The problem with the squirrel man’s answer (“Yep. It works.”) is the same problem I have with nuclear deterrence. Just because there’s been an absence of nuclear war doesn’t mean nuclear deterrence is doing its job. After all, just because there had never been a hurricane of the force and size of Sandy over the last 100 years didn’t prove that Sandy could never happen.

Deterrence is by definition a non-observable phenomenon. It goes on inside someone’s head and can’t be measured or recorded. A leader who is deterred has a strong interest in denying that deterrence had anything to do with his decision afterward. You can’t observe deterrence and you can’t necessarily rely on the testimony of participants afterward. Which makes it a tricky subject to pin down.

Deterrence is usually proved by absence, the way the squirrel man proved his day-glo squirrel was working. I threaten you, telling you not to do something. Then when you don’t do it, I claim success. But the fact that there’s been no nuclear war doesn’t prove that we’ve got an ironclad method for preventing it.

One way to see if nuclear deterrence is working is to set a fairly clear set of criteria for success and then go back over the evidence and see if it looks like the criteria have been met. Since nuclear deterrence proponents generally argue that nuclear weapons induce caution, I’ve gone back to look for instances of rashness and aggression. And found a surprising number. It’s unnerving.

Moving the goal posts

One way that proponents of nuclear deterrence answer these objections is to say that nuclear deterrence worked, it just didn’t work in the way I’ve defined it. The problem here is that this seems to me like moving the goal posts.

For example, I think John Lewis Gaddis moves the goal posts in the Berlin crisis. The Berlin crisis of 1948 was the one that led to the famous Berlin Airlift, in which West Berlin was supplied by air after the Soviets cut off ground and rail access to the city. The crisis began in April 1948 and in June word “leaked” to the press that B-29 bombers had been redeployed to England. The B-29 was the bomber that dropped nuclear weapons on Japan and it was widely assumed (and the Truman administration intended it to be widely assumed) that the bombers in England were nuclear-capable. They weren’t. Only one squadron had been specially modified to be able to dropped the hefty nuclear bombs of the day, and it was still in New Mexico. But everyone took it to be a nuclear threat.

The threat was clearly a failure. On the face of it, it did not resolve the crisis. The redeployment was made in July 1948, the crisis didn’t resolve itself until May 1949–11 months later. It would be ludicrous to try to argue that the Soviets ignored the danger of nuclear war for 11 months and then suddenly were so overwhelmed with fear that they capitulated and ended the blockade. So it looks pretty clearly as if nuclear deterrence failed.

But the nuclear threat is described by Gaddis as a success. He sees it as a success, rather than a failure, because he’s redefined the purpose of the threat. The threat’s purpose wasn’t to resolve the crisis, the threat’s purpose was to prevent the crisis from getting worse. Truman moved bombers to England in order to keep the Soviets from, for example, shooting down the US supply planes that were flying into Berlin. And, according to Gaddis, it worked. The crisis did not escalate.

Of course, Gaddis could be right. No one in the Truman administration ever said what the purpose of the threat was–it was an entirely implied threat: no public statement was ever made defining the goal of the redeployment.

But it makes little sense to think of it as an attempt to head off escalation. If you’re in a crisis, and there’s a problem, and you’re thinking of threatening nuclear war, you do it in order to solve the crisis, not to keep the crisis from getting worse. How often have you thought, “Wow. Things are bad. I’d better take extraordinary measures to keep them from getting worse”?

Most tellingly is the attitude at the time toward nuclear weapons. In 1948 nuclear weapons were new. No one knew what their capabilities were. No one had ever tried to use them in a crisis. Initial assessments in 1945 had been that the ability of nuclear weapons to influence events was limitless. It would make sense, knowing what we know now about the failures of nuclear deterrence to influence events, to imagine that the Truman Administration assigned an appropriately limited objective to their nuclear threat. They just wanted it to keep things from getting worse. But imagining that the Truman administration understood the limits of nuclear deterrence is to imagine that they understood the multiple failures that we know about now. They had no such knowledge. In their minds nuclear weapons were the miracle weapon that had suddenly and unexpectedly forced Japan to surrender. Why wouldn’t you try to use a miracle weapon to resolve the crisis?

But even if you accept Gaddis’s redefinition of the purpose of the threat, there’s a further problem. Because in 1950, when the Korean war broke out, the United States repeated the trick with the B-29 bombers. They shifted bombers to Asian bases and then made the information about that redeployment public. Some people argue that the move was designed to keep the Soviets from entering the war–and it worked. But I look at the move and notice that it didn’t really prevent the war from getting worse. True, the Soviets didn’t come in on the side of the North Koreans. But the Chinese did. Which seems like a failure to me.

There is a fallback to explain this failure, though. I have heard people argue that the redeployment was actually not intended to keep the Chinese from entering the war–there was no way to stop them from entering the war–it was intended to keep them from invading Formosa and Taiwan when they did. And therefore it worked. This is like the witch doctor whose patient dies and the angry relations say, “You said the potion would cure him!” And he says, “Yes, but the potion prevented a great deal of pain.” If you’re adroit at redefining success, magic always works.

Because nuclear threats are rarely entirely explicit, it’s always possible to change somewhat the purpose of the threat. It feels to me as if proponents of nuclear deterrence are always moving the goal posts in order to make nuclear deterrence successful. Deterrence failures are more frequent and less talked about than anyone would like to admit, I think. I talk about this more in my book. (Yeah, a little crass attempt at book selling there.)

Goal post movers, instead of setting clear criteria and then looking for fair tests in the evidence of history, redefine nuclear deterrence as that magic-whatever-it-is-process that prevents nuclear war. And then, since there’s been no nuclear war, claim that it obviously works. Unfortunately, there are enough instances where nuclear war was avoided by luck that this notion of a smoothly functioning doctrine doesn’t hold up. The evidence from the Cuban Missile Crisis is particularly clear: we avoided nuclear war by sheer, dumb luck. If the U.S. fighters had happened to run into the Soviet fighters while both were looking for the lost U-2, nuclear weapons would have been detonated over the Soviet Union. And odds are that that would have led to nuclear war. Claiming that nuclear war was averted during the Cuban Missile crisis because deterrence worked especially well is to ignore the facts.

 

Batting .333 in the Gulf War

Last but not least, let’s look at what happened in the Gulf War. This episode matters in part because General Kevin Chilton (at one time commander of all U.S. nuclear forces) argued in Strategic Studies Quarterly that it was proof that deterrence worked. Remember this threat? After Iraqi forces had invaded and occupied Kuwait in 2000 (but before Coalition Forces had begun their counterattack) U.S. Secretary of State James Baker delivered a letter to Saddam Hussein. In it President Bush (senior) told Saddam not to use chemical or biological weapons in the coming conflict. If he did, the United States would respond with “the strongest response possible.” And the Iraqis didn’t use chembio weapons. Chilton points to this episode as proof that nuclear deterrence works.

But if you go back and read the letter Baker delivered, you find that it actually draws three red lines in the sand: don’t use chembio, don’t set the oil wells on fire, and don’t make terroristic attacks against our friends and allies (Israel). And as we all know, the Iraqis did two out of three of those: they set the oil wells on fire and they launched scud missile attacks against Israeli civilians. So are we arguing that nuclear deterrence only works one third of the time?

In baseball, if you bat .333 you’re doing really well. You can make a lot of money if you get a hit every third time you come up to the plate. But nuclear deterrence is not baseball. If it only works one third of the time, that is not nearly good enough. I’m not claiming here that based on this one episode we can deduce how often nuclear deterrence works. I’m just trying to figure out how reliable nuclear deterrence is? That’s the sixty-four dollar question.

There’s no question that ordinary deterrence (the kind that deters children in everyday life or people from committing crimes) works some of the time. Even though there are still murders (some people are not deterred by the threat of capital punishment), still, capital punishment probably does deter some people some of the time. And there’s little doubt that nuclear deterrence probably works some of the time. Nuclear war is pretty scary. But “some of the time” isn’t good enough. Because any failure of nuclear deterrence could lead to a catastrophic nuclear war. When the stakes are so high, nuclear deterrence has to be 100 percent reliable. As Martin Hellman is fond of pointing out, even if the risk of a catastrophic outcome is relatively small, we still have to take it very, very seriously. And a catastrophic nuclear war would be devastating in a way that it is difficult for us even to imagine. You could say that with nuclear deterrence, failure is not an option. But the evidence seems to show that the risk of nuclear deterrence failing is much greater than we have complacently told ourselves.

Some people argue that over time proof by absence becomes more persuasive. Every day that the sun rises again is further proof that it will rise tomorrow. They look at the last sixty years, count the number of days we haven’t had a nuclear war and conclude that that’s pretty good evidence that deterrence is working. But I’m a historian and we historians take a somewhat longer view. Human history–events we have some real record of–goes back about 6,000 years. Across the course of that span of time, war has shown itself to be a remarkably durable and stubborn accompaniment to human civilization. If you take 6,000 years as the time frame of human history, drawing conclusions about the likelihood of war from evidence over the last 60 years is drawing conclusions based on 1 percent of the evidence. Doesn’t strike me as too large a sample, actually.

 

The evidence of clear failures of nuclear deterrence throughout the Cold War record is undeniable. None of those failures led to nuclear war, but there were plenty of times when the risk of nuclear war did not cause leaders to pull back and be cautious. Far from being perfect, there were, on the contrary, a significant number of times leaders acted aggressively and made matters worse despite the risk of nuclear war. Which raises the question: How can we rely for our safety and security on a process that doesn’t seem very reliable? Particularly where the costs of failure are so high?

If we are to base our safety and security on nuclear deterrence, it has to be a doctrine that works, not a joke about pink squirrels.t

Update | 10:24 pm 25 February 2013 Our reader friend sends along a fourth, high resolution video in which the narrator explains that the missiles on stationary launchers were to fired from inside the building, through openings in the roof.  No, I don’t understand why.

The other day, a reader got in touch with some interesting news.

This was no normal reader, mind you, but the same person who trekked to Halabiye after the Israel strike on what turned out to be a covert nuclear reactor under construction near Dair Alzour (or Al Kibar, if you prefer. Or Deir ez-Zor  Or Dayr al-Zawr. Or Der Ezzor. Or Deir Azzor. Or D’yer Mak’er.)

At the time, this person was able to confirm that the earthen berm constructed by Syria did, in fact, block the sightline up into the valley in which the reactor was nestled (Tourist Trip To Halabiye, 28 October 2009). The reader did not manage to get closer, owing to the efforts of Syrian security posted at the bridge.  The story remains one of my favorites, although I must strongly encourage readers never to do anything like this again.

Anyway, same-said reader emailed me a trio of videos demonstrating that Syrian opposition forces have overrun the former reactor site.  I started looking at the videos yesterday, got hung up on identifying the missile in the building, and then decided to take the kids to the pool.  It was an afternoon well spent sipping wine in a hot tub, but the result is that by this morning, Reuters’s Khaled Yacoub Oweis had me scooped.  Living well is still the best revenge.

Back to work.  The Syrian opposition does appear to have over-run Al Kibar — unless ARK is renting out Elstree Studios.  Here are links to the three videos, along with comments:

 ***

1. السيطرة بشكل كامل على مقر الكبر النووي من قبل لواء جعفر الطيار وجبهة النصرة 22 2 2013 (“Full control over the al-Kibar nuclear site by Jaʿfar al-Tayyār brigade and al-Nusra front.”)

[From Google Translate, I make the title something like: 22 February 2013 Fully in control of the Al Kibar nuclear site by Jafar [his honorific works out to be "the pilot" which can't be right.] and the FSA.]

This is the money video that establishes the location — I’ve stitched together screen captures for comparison with an overhead image.  The two structures, including the blue building constructed on top of the destroyed reactor, are dead ringers, as are some of the more subtle terrain features.  I’d call this a high confidence identification.

2. 2013 صوير ثاني لصاروخ السكود الذي تم السيطرة عليه من قبل الجيش الحر في مقر الكبر النووي المحرر 23 2 (“Second picture of the Scud missile, over which full control was established by the Free Army in the liberated al-Kibar nuclear site.”)

[Again from Google Translate, something like Second Scud Missile under control of the Free Syrian Army at the Al Kibar nuclear site.]

This is the interesting video.  Scud missile?  That’s not good enough! As I have noted before, the late (great) Ze’ev Schiff reported that North Korea sold Libya and Syria something called (we call?  they call?) the Scud D.  After Libya coughed up its Scud C missiles, the range appeared to confirm Schiff’s reporting. ”When Libya gave up its MTCR-class missile programs in 2003,”  the US side told the Russians in leaked, not-safe-for-work accounts of the Joint Threat Assessment, “it showed the U.S. a missile it called the ‘Scud-C.’ However, it had a longer range than the missile we refer generally refer to as the Scud-C.”  Sounds like a Scud D to me!

So which one are we looking at?  A plain ol’ Scud?  Or something more interesting?  For comparison, here are Iranian Shahab 1 and Shahab-2 missiles which correspond to the Scud and Scud C. The problem is that I just don’t know enough about missile details to try and ponder whether we’re looking at a run-of-the-mill Scud or something really interesting.

3. 2013 قاعدة اطلاق صواريخ سكود في مقر الكبر النووي المحرر بالكامل 22 2 (“Complete launch base of the Scud missiles in the liberated al-Kibar nuclear site.”)

More of the same, but included for completeness or at least the aspiration towards.

***

Here is the full text of the Scud-D story.  ’Twas lifted from a bulletin board, so one may wish to check for accuracy.

Syria adds new long-range Scud to arsenal

By Ze’ev Schiff, Ha’aretz Military Editor

North Korea has supplied a new, longer-range Scud ballistic missile to Syria  and is in negotiations to sell the weapon to Egypt as well.

The Scud D, whose range is estimated to be 700 kilometers was unknown  until recently. The original missile, which was made by the Soviet Union, is  known as the Scud B, and most Arab countries with Scuds have Scud B  missiles in their arsenals. Its range is approximately 300 kilometers.

North Korea developed a newer version, the Scud C, with a range of 500 kilometers. Syria acquired that version and has begun assembling them in a local plant set up by the North Koreans. It is also possible that Syria has begun producing Scud parts. Western sources estimate that Egypt has also become involved in producing Scud C missiles.

The Scud D is believed to have been sold to Syria and Libya. While its range  is estimated at 700 kilometers, Syria only needs a 500-kilometer range to cover most of Israel, although it seems that Damascus’ intention is to be
able to deploy the new missile deeper in its territory while keeping Israel within range.

It is not known whether the payload of the new missile is any different from its predecessors or if its guidance system is any more accurate.

What is certain is that Syria has taken a great leap forward in terms of its missile arsenal. Before, Damascus assembled missiles from parts purchased from other countries – none of the missile parts were produced in
Syria. Now Syria has acquired the ability to make some missile parts on its own, though it still must buy some parts from other countries. In its efforts, Syria is closely cooperating with Iran, which is providing Damascus with
rocket fuels.

Syria also possesses chemical warheads for its missiles. It is estimated that Damascus has more than 300 missiles and 26 launchers, in addition to dummy launchers.

Libya is also showing renewed interest in acquiring and developing missiles. After sanctions for its role in the downing of Pan Am 103 over Lockerbie in 1988 were lifted, Tripoli renewed its missile-acquisition efforts. The Libyans are also showing interest at North Korean missiles with a 1300-kilometer  range, which served as the prototype for the Iranian-made Shehab-3.

http://www3.haaretz.co.il/eng/scripts/article.asp?mador=14&datee=05/29/00&id=79746

Update | James says I misrepesented his method, which I may well have done.  He is going to post a comment that explains his method in better detail than I have apparently done.

Apologies that it took so long to post the companion piece on yield estimation to my Foreign Policy column, North Korea’s Big Bang.

The good news is that there are now several yield estimates that help illustrate the point I want to make: Early yield estimates are very rough approximations.

You will undoubtedly notice the very large range.  I still think the best thing is to say the event was “several kilotons” or “on the order of ten kilotons” (as opposed to 1 or 100.) But the most important information to convey is that these are approximate yields based on a well-understood but rough method.

Some of the difference is explained by differences in estimating the magnitude of the body wave generated by the explosion, which ranges from 5.0 to 5.2.

But a much greater discrepancy arises from the equation that is used to model the geology of the test site and the resulting relationship between the size of the explosion (yield) and body wave (Mb).  This equation is normally given in the form of Mb = A + B Log (Yield).

This equation differs from test site to test site, and while a good fit can be achieved, it is far from perfect.  Here, for example, is some data from the then-Nevada Test Site (now Nevada National Security Site) that is used in the foundational study by Nuttli (1986) to give us the canonical equation: Mb = 4.05 + 0.75 log (W), where W is yield.

Reported yield and reported Mb are the actual data.  ”Expected yield” is what one would expect based on the equation given the reported Mb. “Expected Mb” is what one would expect based on the equation given the reported yield.

So, for example, the 4.8 Mb event had a reported yield of 35 kilotons — much greater than the 10 kilotons that would expect based on the equation.  Several events with different yields have the same Mb.  There is nothing wrong here, it’s just that the physical relationship is an approximate one. A usefully approximate one.

Now, Nevada is not a perfect example — seismic waves don’t propagate all that well at the Nevada National Security Site.  As a result, the yields for a given Mb in Nevada are a lot higher than in North Korea, which may lead to some head-scratching.  (Blame the terroir!)  Also, the data is noisier than it would be if we could make the model out of reliably reported North Korean events.

The major take-away is that while it’s a good fit, the standard method is not all that precise.  In the Nuttli paper, he had a standard deviation of 0.2 Mb units.  That’s quite a lot.  (Later work seems to suggest that corrections for bias can get that number down to about 0.1 Mb unit.)

It is very hard to know what the proper relationship is for the North Korean test site.  James Acton did something rather clever, assuming that the 2006 and 2009 tests were at the same depth, which allows him to assume that B=1.  Fitting a line to two data points does not inspire huge confidence, especially when we don’t know the yield, location, and depth of burial, but it is better than not doing it at all and probably more appropriate than using Nuttli’s equation for Nevada or Murphy’s equation for Semipalatinsk, Lop Nor, and Pokhran.  The Chinese seismological community takes a similar approach, using Mb = 4.25 + 0.75 Log W for events of more than 1 kiloton — the Bowers et al equation for Novaya Zemlya — based on three chemical explosions detonated in 1998.

As James is careful to point out that, these are back-of-the-envelope calculations that are used to help us start sorting through what this might mean.  So, for example, we have a general sense of whether the test was successful (seems so) and whether it was a thermonuclear device (seems not, with some qualifications).

Competent seismologists — i.e., not policy hacks like myself or lapsed physicists like James — will come along and make much more sophisticated estimates. This will take some time and, I am sorry to tell you, almost certainly fail to produce a definitive result.  Debate still exists about the yield of the 2009 event.  The relevant literature illustrates a number of more sophisticated ways to estimate yield, none of which agree.  While the US intelligence community placed the size of the 2009 test at approximately 2 kilotons, open-source estimates — including work done at Livermore and Los Alamos — range from 2 kilotons using wave-form coda to more than 5.7 kilotons using hydrodynamic calculations and satellite images.  Nice to see Livermore and Los Alamos can still disagree.  I would write a literature review, but I am not a seismologist and I find this stuff very, very dense.  Feel free, in the comments, to do so, and to add any corrections.

So, for the DPRK test, my advice is for everyone to take a deep breath.  The explosion was clearly bigger than the last.  There is no harm in making rough yield estimates, provided we are all as careful as James.  But let’s not take any of this too seriously just yet.