North Korea’s nuclear tests still triggering earthquakes years later — Study

North Korea’s underground nuclear test explosions at Mt. Mantap have reactivated dormant faults and triggered seismic activity that continues to grow in frequency and magnitude, according to a report by The Debrief.

An international team led by Chengdu University of Technology, working with South Korea’s Pusan National University, found that seismic events from these reactivated faults may be difficult to distinguish from natural tectonic activity, with implications for monitoring former nuclear test sites.

North Korea conducted six underground tests at Punggye-ri between 2006 and 2017, the last estimated at 100 to 250 kilotons, registering a magnitude 6.3 event and causing significant ground deformation at Mt. Mantap’s summit.

Lead author Xingli Fan and colleagues analysed regional seismic records, identifying 1,399 local earthquakes between 2008 and 2025 — far exceeding previous counts. Unlike earlier tests, activity following the 2017 explosion spiked weeks later and has intensified through 2025, concentrated along two previously unrecognised fault structures, suggesting “persistent and organized fault reactivation.”

The study was published in Science.