On January 24, 2013, North Korea announced that it was planning a third nuclear test. The DPRK's National Defense Commission issued a statement saying that "the DPRK makes no secret of the fact that it will continue to launch satellites and carrier rockets and conduct higher-level nuclear tests to target its arch-enemy, the United States, in the dueling war against the U.S.".
A message from the China Earthquake Network (CEN) said a magnitude 4.9 earthquake struck North Korea at 10:57 a.m. on Feb. 12 at a latitude of 41.3 degrees north and a longitude of 129.0 degrees east, at a depth of 0 kilometers. South Korea's Ministry of National Defense confirmed that North Korea is conducting its third nuclear test. The Ministry of National Defense speculated that the yield of this nuclear test by North Korea exceeded 10 kilotons (the yield of the atomic bomb dropped by the United States on Hiroshima, Japan, was about 16 kilotons). The South Korean military also officially entered a state of emergency on the same day in response to North Korea's nuclear test. South Korea and the U.S. have elevated their intelligence and surveillance posture toward North Korea by one level.
OK, don't even mean it LZ, I'm not a nuclear weapons expert! But this nuclear test was underground, so it shouldn't be too contaminated (theoretically speaking from a nuke illiterate person, lol!)
"The geographic scope of the background survey of the nuclear radiation environment is determined by the operational scale of the source unit, for large nuclear facilities for the evaluation of environmental parameters generally to be investigated up to 80km. in other words, the general range of radiation in the 80KM within the impact of some of the larger." (This is my Baidu to reference, huh? Wish you new you happy!)