Comment on Underwater Explosion (UWE) Analysis of the ROKS Cheonan Incident by S.G. Kim and Y. Kitterman

Abstract

The analysis of the seismic and infrasound data recorded at the time of the Cheonan incident led Kim and Gitterman (this journal, published on line August 2012) to conclude that a non-contact underwater explosion had sunk the ship. They also concluded that one of the mines deployed by the South Korean Navy many years ago in the area and then abandoned sank the ship. Their mine theory that is based on the explosive charge weights they calculated by means of two methods using the bubble period determined by their analysis, however, appears to be invalid. Although the incident had occurred in a shallow sea with a depth of less than 50m, the authors used the methods that are applicable only to free-field underwater explosions. The consideration of the influence on the bubble period of the nearby sea surface and bottom and the nearby ship’s hull would double the calculated weights. In addition, the authors ignored several evidences that support the torpedo theory. One of them is aluminum-containing white powder found in large quantities at certain substrates in the retrieved Cheonan. However, the conclusion of the official investigation group that the torpedo was made in North Korea is based on a circumstantial evidence and is yet to be proven with other more direct evidences.