People walk by a screen showing the news reporting about an earthquake near North Korea's nuclear facility, in Seoul, South Korea, Wednesday, Jan. 6, 2016. South Korean officials detected an "artificial earthquake" near North Korea's main nuclear test site Wednesday, a strong indication that nuclear-armed Pyongyang had conducted its fourth atomic test. North Korea said it planned an "important announcement" later Wednesday. The letter read "5.1 Earthquake near North Korea's nuclear facility." (AP Photo/Lee Jin-man)