South Korean passengers watch TV news reporting North Korea’s apparent nuclear test, at the Seoul train station on February 12, 2013. North Korea’s apparent nuclear test had an explosive yield of between six and seven kilotons, South Korea’s defence ministry said, revising its earlier estimate of 10 kilotons or more. Ministry spokesman Kim Min-Seok said seismic monitors had detected a tremor with a 4.9 magnitude emanating from the North’s nuclear test site. AFP PHOTO / KIM JAE-HWAN