2013 North Korean nuclear test On 12 February 2013 , North Korean state media announced it had conducted an underground nuclear test , its third in seven years . A tremor that exhibited a nuclear bomb signature with an initial magnitude 4 . 9 ( later revised to 5 . 1 ) was detected by The China Earthquake Networks Center , Comprehensive Nuclear - Test - Ban Treaty Organization Preparatory Commission and the United States Geological Survey . In response , Japan summoned an emergency United Nations meeting for 12 February and South Korea raised its military alert status . It is not known if the explosion was nuclear , or a conventional explosion designed to mimic a nuclear blast ; as of two days after the blast , Chinese , Japanese , and South Korean investigators had failed to detect any radiation . Test . On 12 February 2013 , a spokesman for North Korea ' s army command said it had successfully conducted a third underground nuclear weapons test , according to the Yonhap . North Korea also said the test had used a miniaturized nuclear device with greater explosive power . Before North Korea announced they had conducted the test , seismic activity had already been detected in North Korea by the USGS , near the site of previous nuclear tests at Mantapsan in Kilju County . A large tremor , first estimated at magnitude of 4 . 9 , was detected in North Korea and governments in the region were trying to determine whether it was a third nuclear test . The USGS upgraded the magnitude of the possibly nuclear tremor from 4 . 9 to 5 . 1 , located east - northeast of Sungjibaegam , North Korea . The tremor occurred at 11 : 57am KST ( 2 : 57am UTC ) and the USGS said the hypocenter of the event was only one kilometer deep . Later , the Geophysical Service of the Russian Academy of Sciences did not register any seismic events and underground tremors at 16 : 00 local time on 12 February 2013 , in the Russian Far East . The China Earthquake Networks Center ( Abbreviation : CENC ; ) also reported this event , putting the magnitude at M 4 . 9 . The tremor caused by the test could be felt by residents of the neighboring city of Hunchun and Antu , in Yanbian , Jilin Province , China . A citizen of Hyesan , Ryanggang Province of North Korea , west from the nuclear test site , reported that many 5 - and 7 - floor buildings shook very severely , and this caused cracking . Yield estimates . South Korea ' s defense ministry said the event reading indicated a blast of 6 – 7 kilotons , later revised to 6 – 9 kilotons using the Comprehensive Nuclear Test Ban Treaty Organization ’ s calculation method . The Korea Institute of Geosciences and Mineral Resources estimated the yield as 7 . 7 – 7 . 8 kilotons . Some experts estimate the yield to be up to 15 kilotons , since the test site ' s geology is not well understood . The Russian Defence Ministry said the power of North Korea ' s nuclear test blast surpassed 7 kilotons . NORSAR compared the seismic data from all three North Korean nuclear tests and estimated the yield of the 2013 test as approximately 10 kilotons . However , the Federal Institute for Geosciences and Natural Resources , a state - run geology research institute in Germany , estimated the yield at 40 kilotons . On 2013 June 19 , the University of Science and Technology of China had released a report that claimed that they had found the precise location of the test at Latitude 41 degrees 17 minutes 26 . 88 seconds , longitude 129 degrees 4 minutes 34 . 68 seconds with an error margin of mere 94 meters and the yield at around 12 . 2 kt , with a margin of error of 3 . 8 kt . In comparison , the atomic ( fission ) bombs dropped by the " Enola Gay " on Hiroshima ( Little Boy , a " gun - type " atomic bomb ) and on Nagasaki by " Bockscar " ( Fat Man , an " implosion - type " atomic bomb ) had blast yield equivalence of 16 and 21 kilotons respectively . Further tests . On February 4 , 2013 , a South Korean military official had stated that there was a " chance that the southern tunnel is a decoy , but we are not ruling out that the regime will conduct nuclear tests simultaneously at both tunnels . " On February 15 , 2013 , North Korea had told China that they were preparing for one or two more nuclear tests this year . On April 8 , 2013 , South Korea had observed activity at Punggye - ri , suggesting that a fourth underground test was being prepared . It was later believed that the tunneling activity that started in April was for a long term project , and that a nuclear test wouldn ' t occur soon . According to a U . S . expert , North Korea has everything in place for a fourth explosion but is hesitating due to the fear that it would anger China . Reaction . In response , Japan ' s Prime Minister , Shinzo Abe , called an urgent security meeting of the United Nations Security Council . The emergency session was to be held 9 AM EST on February 12 , 2013 . Tibor Toth , executive secretary of the Comprehensive Nuclear - Test - Ban Treaty Organization Preparatory Commission ( CTBTO ) , confirmed the event ' s location was " roughly congruent with " nuclear tests carried out by North Korea in 2006 and 2009 . Japan ' s Kyodo News service reported the Japanese defense ministry had scrambled aircraft to hunt for radiation effects . Japan ' s government held a national security council meeting in Tokyo according to NHK . The South Korean military also raised its readiness level . In general , international reactions to the 2013 North Korean nuclear test have been almost uniformly negative .