Using GPS To Detect Secret Nuclear Tests

Harperdog writes "This article details how GPS can help detect secret nuclear tests, giving the US more reason to ratify the Comprehensive Test Ban Treaty. Here's a quote about the 2009 North Korea test: 'At the time, however, the May 25 bomb also sent a different signature, this one into the atmosphere. It did not release radioactive gas or dust, as would be the case for a bomb detonated on the Earth's surface. Rather, it released a shockwave — a bubble of disturbed air that spread out from the test site across the planet and high into the ionosphere. ... We quickly gathered data from 11 GPS receivers — six belonging to the South Korean GPS network and five belonging to the International GNSS Service and scattered around Eastern Asia. The data indicated a sudden spike in atmospheric electron density just after the underground test.'"