Was the "Critical Evidence" presented in the South Korean Official Cheonan Report Fabricated?

Abstract

South Korean Joint Investigation Group (JIG) [1] presented two "critical scientific evidence" that link the sinking of the South Korean navy corvette Cheonan on March 26, 2010 to the alleged explosion of a North Korean torpedo: the now-infamous "No. 1" blue ink mark on the torpedo, and the electron-dispersive spectroscopy (EDS) and x-ray data of the three "adsorbed materials" extracted from the ship, the torpedo and a small-scale test-explosion. In our previous paper [2], we described the inconsistency of JIG's EDS and x-ray diffraction (XRD) data. Here we report our SEM, EDS, and x-ray experiments on an Al powder that underwent melting followed by rapid quenching, and our simulation of the EDS spectra of Al2O3 and Al(OH)3. We obtained an experimental value of 0.25 for the EDS intensity ratio, I(O)/I(Al), and a simulation result of I(O)/I(Al) ~ 0.23 for Al2O3 formed on the surface of the adsorbed materials during an explosion. The JIG's EDS data, however, showed very different values of ~ 0.9 for the same ratio. Interestingly, the high value of ~ 0.9 is expected for "rusted" aluminum, such as Al(OH)3, that can be formed by exposing Al to moisture or water. Our results indicate that the JIG's adsorbed materials taken from the ship and torpedo are not associated with any explosion, and that the JIG's EDS data of their test-explosion sample are most likely fabricated. Until the South Korean Joint Investigation Group (JIG) can convince the international scientific communities the validity of their data, their official conclusion that the torpedo sank the Cheonan ship should be discarded.