Concern rises about radioactive pollution if North Korea conducts another nuclear test
Quirks & Quarks ·
The 'artificial quake' in North Korea on September 3, thought to be its sixth nuclear test, was five to six times more powerful than the tremor from Pyongyang's fifth test. Since then, North Korea has also experienced three more 'earthquakes.' (JUNG YEON-JE/AFP/Getty Images)
