Smoke But No Fire?

The South Korean Yonhap news agency is reporting that a huge mushroom cloud over two miles wide was sighted in North Korea's Ryanggang Province last week, near the Chinese border. A large crater can be seen from orbit. The blast coincided with the anniversary of North Korea's founding on September 9. Over 150 people were killed in an explosion at the Ryongchon Railway Station in April. The area is mountainous, thinly-populated, and site of a major military base and a missile launching facility.

Many news agencies are hinting that the latest event may have been a nuclear weapons test, but the U.S. Geological Survey web site shows no corresponding seismic event. Any sufficiently large release of energy near the surface would also cause a mushroom cloud. It could have been a large conventional explosion (which could be part or a nuclear weapons program), or even just a forest fire.