January 2016 North Korean nuclear test
North Korea conducted its fourth nuclear detonation on 6 January 2016 at 10:00:01 UTC+08:30. At the Punggye-ri Nuclear Test Site, approximately 50 kilometres (30 miles) northwest of Kilju City in Kilju County, an underground nuclear test was carried out.
Source: Wikipedia — January 2016 North Korean nuclear test (CC BY-SA 4.0)