The ROKS Cheonan
*note* KCNA links only work for Japanese IP addresses, alternative links are listed in citations
Summary
The Joint Civilian-Military Investigation Group report on the sinking of Republic of Korea naval vessel ROKS Cheonan is based on faulty science, manufactured evidence, and ignoring any opposing evidence. Evidence points to a mine explosion as a potential cause of the sinking, likely a mine laid by the Republic of Korea Navy. The sinking was used by the right wing in the ROK in an attempt to solidify power and discredit leftists as 'too soft' on the DPRK. It was used by the United States as a way to strengthen alliances and increase military control in the region. Dissent against the US/ROK narrative in the ROK was suppressed in an attempt to hide the reality of the situation. Despite consistent push by the DPRK, China, and peace advocacy groups in the ROK, the government has refused to launch additional investigations into the incident.
Sinking of ROKS Cheonan and JIG Report
On March 26 2010, the ROKS Cheonan, a Republic of Korea naval ship sank off the coast of Baengyeong island, killing 46 people. This event was blamed on the DPRK initially by some groups, and an initial report was released on May 20 "conducted by the Joint Civilian-Military Investigation Group of the Republic of Korea with the participation of international experts from Australia, Sweden, the United Kingdom and the United States, and the Multinational Combined Intelligence Task Force, comprising the Republic of Korea, Australia, Canada, the United Kingdom and the United States" [1]. The finalized version of the report was released in September 2010 (from here on referred to as the 'JIG report') and agreed with the initial report [2 - finalized report]. The report claims that a non-contact explosion caused a "strong shockwave and bubble effect causing the splitting and the sinking of the ship", based on physical evidence on this ship, seismic evidence, the bodies of those killed, and witness statements [1]. This claim isn't disputed by the DPRK or a later Russia Navy analysis, which stated the sinking was caused by a "non-contact explosion below the ship" [3]. The JIG report also claims that investigators found "propulsion parts" matching the "specifications on the drawing presented in introductory materials provided to foreign countries by North Korea for export purposes", and that the writing on the parts was "consistent with the marking of a previously obtained North Korean torpedo" [1].
Fig 1: writing 'similarities' on the fragments allegedly found in Cheonan wreckage (left) [1]
Russian Navy Report
The Russian Navy report notes a number of discrepancies and errors in the JIG report. They acknowledge the torpedo parts may have been manufactured in the DPRK, but note that the writing is in the wrong place. The Russian Navy report also claims that the torpedo appeared to be underwater for at least six months based on visual examination. While the JIG report claims the explosion occurred at 21:21:58 (hour:minute:second), the CCTV image in the ship cut off at 21:17:03, and soldiers reported injuries with their cell phones beginning at 21:12:03, almost ten minutes before the JIG report claims the explosion occurred [3].
The Russian Navy report offers an alternative explanation: the explosion of an underwater mine as the ROKS Cheonan ran aground [3]. During the Korean war, naval mines were laid by the DPRK in the same area the the ROKS Cheonan sank. The island the ROKS Cheonan was off the coast of, Baengyeong, is a part of the city of Incheon. In September 1950, according to US naval reports, a DPRK ship was discovered laying mines off the coast of Incheon [4]. Mines were also laid by the ROK in the area in the 1970s. The Russian report states that the damage to the propeller was inconsistent with damage expected from an explosion, as "all wing blades of its right screw (propeller) and two wing blades of its left screw (propeller) were damaged, and the damaged propellers were scratched so baddly [sic] that they became shiny and wide areas of the screws were scratched by friction. The body and the end parts of the aforementioned propeller wing blades were additionally stretched. One wing blade of the right propeller has a metallic crack at the edge" [3]. An explosion could have damaged the propeller, but it the scratches and stretching are consistent with the propeller hitting the ocean bottom. The ROK's explanation for the damage is a sudden stoop of the axle, but the metallic crack isn't consistent with that theory. While the ROK claimed that no fishing zones were in the zone of the ship's voyage, "remnant fishing nets were found entangled around the right screw axle" [3]. The entanglement of the fishing net and damaged propeller may have restricted the maneuverability of the ship, which may have led to it running into a mine.
Bubble Simulation
Dr. Seunghun Lee is a professor of physics at Virginia, and Jae-Jung Suh is a professor of politics and international affairs at International Christian University, specializing in international relations with the Korean peninsula. They argue that the JIG report failed to show conclusive evidence that there was an explosion, that sinking was due to an external explosion, and that the DPRK was responsible for alleged explosion. The simulation used in the JIG report was leaked, and failed to show that a bubble produced by an outside explosion could split the ship in half. Even the ROK defense ministry admitted that "it [had] yet to produce a bubble simulation consistent with the information presented in the JIG report" at the time of Suh and Lee's paper [5]. Suh and Lee claim that a bubble, even if it could split the ship, should show a concave bubble-shaped deformity on the ship, but instead the "bottom of the front part of the ship is pushed up in an angular shape" (see fig. 2) [5]. There also should have been a pre-bubble shock-wave from an explosion outside the ship. Suh used a calculations from Reid [6] to determine that the pressure of that shock-wave should have been 5000 psi, a powerful shock-wave incompatible with the condition of the ship. Somehow "internal instruments and parts remain[ed] intact in their original place; and none of the crew members suffered the kind of injuries expected of such a shock" [5].
Fig 2: Angular deformity of ROKS Cheonan and leaked simulation [5]
The JIG report claims the absorbed materials on the torpedo and the ship matched. This is well proven through XRD and EDS analysis, however the reason these materials matched is less definitive. From the JIG data, the "intensity ratio of the oxygen peak and the aluminum peak in their EDS data of the [adsorbed materials] is very different from that of the alumina, Al2O3, that the JIG argues is formed during the explosion" [5]. This implies that the adsorbed materials were "likely aluminum that has rusted after exposure to moisture or water for a long time", as the intensity ratio better matches aluminum hydroxide (Al(OH)3) [5]. The JIG's own test explosion failed to produce a similar adsorbed material to that on the torpedo and ship. They claimed the difference was due to a slower cooling rate in their test, leading to less oxidized aluminum. However, in a test carried out by Lee heating and rapidly cooling aluminum as would have happened in the explosion, "only a fraction of the aluminum was oxidized", leaving a strong crystal Al signal in XRD analysis [5] (fig. 3). Experiments studying real explosions "reported that the resulting Al-related compounds are crystalline aluminum, crystalline α-Al2O3, and amorphous γ-Al2O3" [7]. Lee claims the EDS analysis of the JIG test sample is incorrect, perhaps entirely faked. JIG declined to release samples of the adsorbed material from the test explosion, claiming they "used up all the AM-III samples", despite the tests performed requiring an extremely minute amount of material [7]. The JIG report claims the supercooling would have led to amorphous aluminum oxide, explaining the lack of an reading in XRD analysis, but Lee's results dispute this claim.
The heavy corrosion on the torpedo part, if the JIG report is correct, would be due to the heat of the explosion burning off the paint. The ink marking which the JIG report has used to link the torpedo to the DPRK remained however. According to Suh and Lee, "ink has a lower boiling point, typically around 150 degrees in Celsius, than paint does – typically 350 degrees Celsius – and thus the ink marking should have burnt away just like the outer paint" [5]. Song Tae-ho, from the Korean Advanced Institute of Science and Technology, responded to this criticism, using the equation PVγ=C to demonstrate that the bubble could have cooled quickly enough for the ink to not melt. Lee addresses this argument by first pointing out that this disputes the JIG's claims that "the 'adsorbed materials' are aluminum oxide stuck to the propeller as a result of the explosion... [and] that the paint on the exterior of the torpedo burned" [8]. With Song's method, the bubble would have been below freezing when it reached the propeller, making it impossible for the aluminum oxide to still be melted or able to adhere. Song's methodology is also simply wrong, as PVγ=C should be used for reversible processes where the pressure inside and outside the bubble remain the same, whereas in reality the "pressure inside the bubble created by an explosion of a 250kg explosive is well over 100 thousand times greater than the pressure outside" [8]. While an exact estimation is impossible, temperature would have been around 1000 degrees when it reached the propeller in reality [8]. While an explosion could have caused the sinking, the JIG report failed to prove that was even possible, much less definitive, and leveling accusations against the DPRK without adequate science was irresponsible and malicious.
Evidence of Mines
The JIG report in August dismissed the possibility of a mine, claiming it was "impossible" due to the environmental conditions of the area and the fact that no other mines were found by later sweeps [2]. They admitted that "a non-contact torpedo detonation causes identical damage as a non-contact mine detonation" and thus the damage profile didn't rule out a mine explosion based on the JIG report [2]. The impossibility of mines in the area is contradicted by locals- a "Baengnyeong Island resident, who has been diving for seafood for more than 20 years, said a number of the other divers there reported seeing mines", and he himself had seen scarring on rocks which "wasn't natural" [9]. An electric engineering specialist who was involved in placement of mines in the area in 1970, speaking anonymously out of fear for retribution from the ROK government, stated that the "land control mines were designed with waterproof casings and fiber-reinforcement polymers to resist corrosion by seawater, and in the testing prior to the fitting of the electrical detonator (a USFK Mark 6), they were sensitive enough to be triggered when the gauge was used to measure their current" [9]. The JIG report claims the mines were planted too long ago, but the waterproofing should have been sufficient, as they were designed to last under ocean water.
The Russian investigative team claimed the netting on the Cheonan shows the ship could have drug a mine from the bottom, leading to the explosion. The JIG report maintains that the ship sunk at a depth of 47 meters, making a mine on the ocean bottom not strong enough to split the ship in half. However, on July 9 "Captain Park Yeon-soo, operation officer on duty the day of the incident, testified that at the time of the explosion, the ship’s equipment showed they were 20m deep" [9]. The JIG investigators have refused to release the ship's route to the public, but still maintain the 47 meter depth. They also claimed the weight of the mine made movement impossible, but "Dr. Lee Pan-mook of the Marine System Security Research Center under the Korea Ocean Research and Development Institute said at the time, “mines can become loosened by currents and are known to float around" [9].
From the JIG report: "the LCM technical expert who had participated in the emplacement of the land controlled mines at the shore of Yeonhwari, Baekryong Island in the late 1970s... emphasized that there is enough possibility, based on the volta battery principle and the experiment in which he found the detonator to be sensitive enough to explode when he measured the electric current with a measuring device. He presented that he had seen measurements of approximately 1V and 5~10mA. However, the explosive experts from ADD assessed that there is low possibility for the explosion of a mine due to naturally induced electric power because most electric power is discharged into the seawater even if it is induced and because there were doubts whether the zinc and copper wire together can produce enough electric power for the detonation" [2]. While the JIG report also claims tests they ran confirmed that the volta battery principle didn't produce any electric current in the wire, Dr. Kim So-Gu, "an expert in big vessel and ship structures... said that electrical charges abound in a vessel, pointing out as example the ICCP unit, which is used to prevent the outer part of the ship from corroding" [9]. This shows that there's a reasonable possibility of detonation of the mines laid in the 1970s.
Based on seismic data from research stations in the area, Dr. So-Gu and Dr. Yefim Gitterman determined that "the seismic yield would be about 136 kg of TNT, which is equivalent to the individual yield of a large number of land control mines... abandoned in the vicinity of the ROKS Cheonan incident by the Republic of Korea (ROK) Navy in the 1970s" [10]. Their findings contradicted the JIG report's claim of a 250 kg of TNT seismic yield, indicating that a mine was more likely.
Submarine Operation in These Waters
The JIG report claims that "the tidal difference, water speed, and wave height are not limiting factors for a torpedo attacks (sic) by a submarine" [2]. However, the dangerous currents and shallow waters make the operation of submarines difficult and the possibility of mistakes made by the ROKS Cheonan crew more likely. Before the JIG report was released, the former ROK Navy Chief of Staff Song Young-Moo said that "Some people are pointing the finger at North Korea, but anyone with knowledge about the waters where the shipwreck occurred would not draw that conclusion so easily" [11]. An expert at a missile manufacturer disputed the JIG report's claim that a Korean People's Army midget submarine could have fired the torpedo, claiming that "Sango class submarines... apparently do not have an advanced system to guide homing weapons... [and] if a smaller class submarine was involved, there is a bigger question mark" [12]. The ability of the DPRK to sink the Cheonan with a torpedo has not been addressed, much less proven by JIG investigators.
The Ink Marking
According to the JIG's own report, they "concluded that the ingredient of the blue ink [on the torpedo] was 'Solvent Blue 5' that had [been] patented by a South Korean company, Monami, and they said that it cannot be traced to North Korea" [8]. They didn't explain how the DPRK could have obtained that ink, and neglected to address that concern at all in the report. One of the initial investigators on the JIG team claimed "The magnified photo of the evidence showed that the marking was written on the rusted surface... [but] if it were the North who marked it, the marking should have been written on a smooth surface" [13]. The photos released to the public in the report don't seem to be detailed enough to be conclusive on this front (unsurprisingly), and the JIG report claims "salt was precipitated on the marking and corroded interior steel was found to be risen above the ink" [2] (see Fig. 1 under 'Sinking of ROKS Cheonan and JIG Report'). It appears in the picture in the JIG report, the ink marking isn't altered by corrosion, as one would expect if the marking had been on the torpedo initially.
The style of writing also may not point towards the DPRK, as "According to Yang Moo Jin, a professor of North Korean studies at Kyongnam University, South Korea, it is not North Korean custom to label numbers with the letter 번 (for example '1번', '2번', '3번'), instead North Korea tends to indicate numbers using the word '호' (such as 1호, 2호, 3호 etc. -- this is pronounced as 'ho' and can be translated as code in English, for example, code 1, code 2...)" [14, translation in 15].
Other Discrepancies
While I think it is bad journalistic practice to lend much credibility to an unnamed source, if we apply the same standard that the US media has with their coverage of the DPRK, a "military expert, who spoke on condition of anonymity, cautiously raised the possibility of an 'internal act of terror'" [11]. Immediately after the explosion on the ROKS Cheonan "another naval ship... opened fire at an 'unidentified object' without rescuing sailors of the sinking Cheonan... [thinking] that an enemy vessel was fleeing after an attack" [16]. However, the defense ministry "concluded that the object on its radar was a flock of birds" [16]. This shows the tendency of the ROK's military to shoot first without confirming an attack, a tendency to remember when analyzing events where it's claimed the DPRK shot first.
The JIG report includes testimonies from survivors of the incident, and none of them reported seeing a water column. However, later in the report the JIG investigators speak of the water column's role in destroying the ship [2]. This contradiction is never explained in the report.
The DPRK told the ROK that they would send an "inspection group through the area under the joint control of the north and the south in the west coastal area" to investigate the site of the sinking "at 10:00 on May 22 and [urged the ROK] to take measures for its field activities including its passage through the Military Demarcation Line and guarantee of its safety" [17]. The ROK refused to allow this group access, stating that the investigation they conducted was correct. The DPRK also offered to provide pieces of their torpedoes in November 2010, claiming that "aluminum alloy fragments prove themselves that the torpedo was not from the north" [18]. If the JIG investigation was sufficient, allowing another party access shouldn't be a problem once the investigation is concluded, as the only danger would be that the DPRK would find contradictory evidence.
The 'international' team of investigators included primarily investigators from allies of the US/South Korean position, with Sweden as the only non-aligned country and no allied countries with the DPRK invited. Sweden's Accident Investigation Board (SHK) assisted with the JIG investigation, but they have refused to entirely support the conclusions of the JIG report. An official involved in the report from SHK stated that the Swedish investigative team was "not in a position to express its position on the findings regarding the responsible party in the Cheonan sinking" [19]. It appears that the Swedish team worked on and supports the conclusion that an explosion caused the damage to the ROKS Cheonan, but not the separate conclusion that the DPRK was responsible.
Who Stands to Benefit?
One South Korean citizen interviewed for a BBC article brought up an important question: "why has North Korea put a signature at the bottom of the torpedo" [20]. If the attempt was to attack the ROK without being caught, using a marked torpedo of a variety the international world knows they produce hardly seems logical. If they were trying to openly attack the ROK they wouldn't have so vehemently denied responsibility.
The DPRK at the time was working to strengthen their economy, and as KCNA notes "development presupposes peace, the DPRK at present requires peaceful external environment more than ever before" [21]. Increased tensions would at best create a new round of sanctions, further harming their economic growth, and at worst create an open war, ruining any hope of developing their peacetime economy. The US on the other hand used the situation to strengthen alliances and to "tighten its military domination over [the region] as evidenced by the order issued by it to its forces in south Korea to be combat ready to cope with another Korean war" [21]. The United States to this day retains OPCON (Operation Control, the power to command troops in a wartime situation) in the ROK. The transition was supposed to occur on April 17 2012, but in June 2010 "in consideration of the changes in the security environment, the two countries agreed to adjust the timing of the OPCON transition... to December 1, 2015" [22, p. 18]. The factors later cited for that shift in decision include "the risk of threat of military provocation through incidents such as the ROKS Cheonan attack" [22, p. 83]. The ROK also engaged in a joint drill with the US and came out with the May 24 Measures', which "restricted economic cooperation, exchange, and human contact between the two Koreas" [23]. These actions show that the US was the primary benefactor of the ROKS Cheonan sinking, and the DPRK's interests were severely harmed by the event.
As KCNA notes, the GNP (Grand National Party, a conservative party in the Republic of Korea now known as the Liberty Korea Party) was facing a serious threat in the local elections of June 2010, as the Democratic Party (which later merged into the Democratic United Party) was growing in strength. KCNA allges that the GNP was attempting to "create 'a security crisis' for the purpose of weathering out its 'election' crisis" [24]. Since GNP runs on a platform of strong military defense and antagonism towards the DPRK, an attack on the ROK by the DPRK would be advantageous, and the GNP began pushing the theory of the DPRK's responsibility well before the May 20 report. The use of the ROK Cheonan sinking for political advantage may have proven to be a failure at first, as in the June elections the GNP lost big in every category, doing slightly over half as well as 2006. In the long run however, this may have helped Park Geun-hye solidify the party's conservative nationalist base.
Popular Reaction and Repression
In a BBC article, surely among the least friendly news organisations to the DPRK, of the six South Koreans interviewed, three expressed doubts about the official report, and only one was in favor of strong retaliatory measures [20]. Shin Sang-chul was initially a part of the JIG investigation, after serving in the ROK navy and working as a ship-builder for seven years. He denied the claim that the sinking was due to a torpedo from the DPRK, and the ROK Ministry of National Defense "formally requested to replace [him]" [25]. On August 26 he was indicted on charges of "defamation for claiming that the government and military have been covering up the cause of the Cheonan sinking, and that the real cause was that the ship had run aground or collided with another object" [26]. Shin was worried that the indictment wouldn't go through, claiming that he would "prove that the investigation team’s announcement was a lie in the courtroom" [26]. On December 7 he was sentenced to three years in prison for libel [27]. According to a study on freedom of expression in South Korea, after the Cheonan incident the "response to the questions and criticisms was not an open debate but suppression, using criminal defamation charges to intimidate the opposition and increasing control over media and social media content dealing with North Korea" [27]. Shin Sang-chul is just one example of the repressive action the ROK government took towards dissenting opinions on the Cheonan. Starting on May 7 the government also investigated Park Sun-won, "former President Roh Moo-hyun’s secretary for national security, on charges that he spread false information about the sinking" [13]. This approach not only is concerning in itself, as it contradicts the western narrative of the ROK's free and open society, but it also casts doubt on the reliability of the JIG investigation- if their approach was sound why is dissent silenced not disproven?
[1]: UN Security Council - Letter dated 4 June 2010 from the Permanent Representative of the Republic of Korea to the United Nations addressed to the President of the Security Council
[2]: Joint Investigative Report on the Attack Against ROK Ship Cheonan
[3]: The Hankyoreh - Russian Navy Expert Team’s Analysis On the Cheonan Incident (27 July 2010)
[4]: Marolda, Edward J. - Mine Warfare (2000)
[5]: The Asian Pacific Journal - Suh & Lee - Rush to Judgment: Inconsistencies in South Korea's Cheonan Report (12 July 2010)
[6]: Reid - The Response of Surface Ships to Underwater Explosions (1996)
[7]: Lee & Yang - Were the “Critical Evidence” presented in the South Korean Official Cheonan Report fabricated? (2010)
[8]: The Hankyoreh - [Column] Pieces of the Cheonan puzzle (5 Aug. 2010)
[9]: The Hankyoreh - New evidence that Cheonan was sunk by an old mine (14 Sept. 2012)
[10]: So-Gu & Gitterman - Underwater explosion (UWE) analysis of the ROKS cheonan incident - Pure and Applied Geophysics 170(4) (Apr. 2012)
[11]: The Chosun Ilbo - What Caused the Cheonan to Sink? (29 March 2010)
[12]: The Korea Times - Questions raised about smoking gun (20 May 2010)
[14]: Left21 - 조사단 발표는 또 다른 의혹을 낳고 있다 (2010)
[15]: LINKS - South Korea: The story of ROKS Cheonan- repression, lies and half truths (1 Sept. 2010)
[16]: The Korea Herald - Military plays down N.K. foul play (2 April 2010)
[17]: KCNA - S. Side Urged to Receive NDC Inspection Group (22 May 2010) (backup)
[18]: Reuters - North Korea offers samples to refute ship sinking (2 Nov. 2010)
[21]: KCNA - Who Got Benefit from "Cheonan Case" (26 May 2010) (backup)
[24]: KCNA - AINDF Calls for Anti-GNP Struggle (19 May 2010) (backup)
[25]: The Korea Times - Gov’t seeks to replace Cheonan investigator (13 May 2010)
[26]: The Hankyoreh - Cheonan investigation team member indicted (27 Aug. 2010)
[27]: Haggard & You - Freedom of Expression in South Korea (18 Aug. 2013)
