PBS Newshour: “North Korea tested its third nuclear device Tuesday at its Punggye-Ri site, the same location of its first two tests in 2006 and 2009. The U.S. Geological Survey recorded an artificial, or manmade, 5.1 magnitude earthquake. The Institute for Science and International Security (ISIS) predicted this nuclear test on Feb. 3, 2013, after evaluating satellite images of the site. Through satellite images, the intelligence community has long been able to detect suspect nuclear reactor sites across the world. Many of these images feature excavated sites of displaced earth, structures resembling the dimensions of a nuclear reactor building, a perimeter of security around the buildings and construction work in progress.”