TMB writes: As reported by CNN, North Korea has conducted its 5th nuclear test, the largest yet at 10 kilotons. Before the test was reported, Slashdot reader hcs_$reboot reported: A magnitude 5.3 earthquake has been detected in North Korea, amid reports the country had been preparing for its fifth nuclear test. South Korea's Yonhap news agency said it had been an "artificial quake." The U.S. Geological Survey said the tremor had been detected in the north-east of North Korea, close to a known nuclear test site. The earthquake occurred close to the surface, the USGS said. The shallow depth and precise timing of the quake suggests it was man-made. North Korea says it has tested a nuclear warhead and that the test showed the warhead "has been standardized to be able to be mounted on strategic ballistic rockets."