# Seismic activity at North Korea nuclear test site > Live situation record from CLSTR: https://clstr.news/situations/seismic-activity-at-north-korea-nuclear-test-site > Updated: 2026-09-20T04:10:31.000Z. Sources: 17. Developments: 2. Research analyzing seismic data from 2008 to 2025 indicates that North Korea’s underground nuclear tests at the Punggye-ri site on Mount Mantap have caused a sustained and accelerating increase in earthquake activity. While seismic disturbances from such tests typically subside quickly, scientists have recorded approximately 1,399 earthquakes in the region, with both frequency and magnitude increasing since the final major test in 2017. Studies suggest that the 2017 nuclear test, estimated at 160 kilotons, may have reactivated long-dormant intraplate faults and potentially exposed previously unmapped hidden faults. Researchers propose a “delayed effect” where the redistribution of crustal stress and the infiltration of groundwater into new fractures increase pore pressure, facilitating movement years after the initial explosions. Geological modeling indicates that the six nuclear tests conducted between 2006 and 2017 weakened the crustal integrity of the area, which had been seismically quiet for roughly 2,000 years prior to the testing program. Although no direct evidence of further nuclear testing has been confirmed since 2017, reports from the IAEA and US intelligence note that repair and restoration activities have been observed at the test site. ## Timeline ### 2026-09-20: North Korea nuclear tests trigger sustained seismic activity North Korean nuclear tests at Mount Mantap have triggered nearly 1,400 earthquakes since 2017, reactivating fault lines and causing a long-term, accelerating increase in seismic activity. 2 sources. https://clstr.news/cluster/north-korea-nuclear-tests-trigger-sustained-seismic-activity ### 2026-09-17: Punggye-ri nuclear tests may have reactivated dormant seismic faults A study in Science shows North Korea's 2017 nuclear test may have reactivated dormant faults, causing 1,399 earthquakes near the Punggye-ri site between 2008 and 2025. 15 sources. https://clstr.news/cluster/north-korea-nuclear-test-site-shows-rising-seismic-activity --- Cite as: Seismic activity at North Korea nuclear test site. CLSTR, https://clstr.news/situations/seismic-activity-at-north-korea-nuclear-test-site