South Korea has detected signs that North Korea is preparing to launch a ballistic missile from a submarine, the South Korean presidential office said Saturday, a day after a U.S. aircraft carrier arrived for joint drills.The South Korean military said there is activity in the North suggesting preparations for the firing of a short-range SLBM off its eastern coastal city of Sinpo, according to South Korea's Yonhap News Agency.Sinpo has production, development and testing facilities for SLBMs, according to Yonhap.The North has repeatedly conducted ballistic missile tests since the start of t…READ FULL ARTICLE