Decade after last blast, North Korean mountain still trembles from nuclear damage
A new study in Science reports that Mount Mantap in North Korea has experienced nearly 1,400 earthquakes between 2008 and 2025, with frequency and magnitude increasing since the 2017 underground nuclear test. The explosions have progressively damaged surrounding rock and altered stress on pre-existing faults, triggering ongoing seismic activity. The 2017 test, estimated at 100–250 kilotons of TNT, caused the most significant disturbance and initiated a cascade of quakes.
The study, drawing on seismographs in China and South Korea plus satellite photos, shows the 2017 blast—estimated at up to 250 kilotons—fractured the mountain's interior and altered stress on existing faults. This triggered a cascade of tremors, with nearly 1,400 quakes recorded from 2008 to 2025, most occurring after that final test.
The site now fits the Cold War label of a "tired mountain," where fractured ground can no longer trap radioactive gases. The ongoing seismicity challenges international monitors, as years-later quakes may blur the line between natural tectonic events and potential new explosions.
The persistent tremors could complicate global nuclear verification, as monitoring agencies may struggle to distinguish aftershocks from new tests, potentially eroding trust in treaty enforcement. For regional neighbors, the unstable mountain could pose a geological hazard, though the site is remote. The findings may also influence future test-site selection, highlighting the long-term environmental and security consequences of underground detonations.