Between 2006 and 2017, North Korea conducted six underground nuclear tests at its vast testing site at Mount Mantap in North Hamgyong province. Typically, underground explosions trigger an intense burst of minor earthquakes that die down once testing stops. But geologists have detected far more seismic activity after the final detonation, and it has persisted for years.
North Korea's nuclear testing may have triggered hundreds of earthquakes over several years
