It's all in the "data"--
GPS Tracks Secret Nuke Tests : Discovery News: "Like earthquakes, underground nuclear blasts send pulses of acoustic energy up through the earth that momentarily disturb the ionosphere. Those disturbances propagate outward through the ionosphere like waves from a stone thrown into a pond. As the ionospheric disturbance passes between a GPS satellite and a GPS receiver on the ground, there is a noticeable blip error in the data. Add together lots of other such errors from the same wave passing between multiple receivers and satellites, and you get a lot of very specific data that points back to a the source. “It's very similar to seismological detection of an epicenter (of an earthquake),” explained Jihye Park, a post-doctoral researcher at Ohio State University. In fact the same methods can be used as those employed by seismologists, she said. They applied their technique to archived data and found clear signals of US nuclear tests from the 1990s as well as underground detonations in North Korea."
I'm sure North Korea is not pleased to know there are "no secrets."
Seguir a @johnyahcom
Russia's risky flybys may be attempts at 'baiting us into shooting first,' top US admiral says - "We're not going to do that first," Adm. Robert Burke said, "but I'm also not going to ask my commanding officers to take the first shot on the chin."