Examine the environmental and geological risks associated with underground nuclear weapons testing, and their implications for regional security in East Asia.

Underground testing contains the fireball, not its consequences. A 17-year seismic study published in Science (2026) finds that North Korea's six tests at Punggye-ri (2006–2017) have reactivated two previously dormant faults beneath Mt. Mantap [1], showing that the geological footprint of a blast outlives the explosion and acquires strategic weight.

Geological risks: induced seismicity that outlives the trigger

• About 1,399 local earthquakes were recorded near Mt. Mantap (2008–May 2025), roughly 1,330 of them after the September 2017 test; the strongest reached M3.4 [1].
• Mechanism: repeated blasts progressively damaged the shallow crust and redistributed stress, letting faults already near failure slip — most quakes occurring within ~1 km of the surface, against ~15 km for natural Korean earthquakes [1].
• Unlike normal explosion aftershocks that decay within weeks, activity here intensified for years [1]. India's own Koyna–Warna case confirms the pattern: over 20 quakes above M5 and ~200 above M4 in six decades of reservoir-triggered seismicity [4]. Humans can switch a quiet fault on; they cannot switch it off.

Environmental risks

• Fracturing of the containment rock raises the prospect of radionuclide seepage into groundwater and soil — unverifiable, since the site was declared closed in 2018 with no inspection access.
• Researchers caution the destabilised zone could yield a larger earthquake; its proximity to the volcanically active Mt. Paektu is a flagged concern, not a proven causal link [1].

Implications for East Asian security

• Hazards are transboundary: tremors and any leakage would affect South Korea, China and Japan, converting a weapons programme into a shared disaster risk.
• Yet monitoring works without access — regional stations in South Korea and north-eastern China tracked the site for 17 years [1], and the CTBTO's International Monitoring System of 50 primary and 120 auxiliary seismic stations [2] detected all six tests, with over 100 stations analysing the 2017 event [3].

Underground testing is therefore neither environmentally clean nor geologically contained. The way forward lies in strengthening verification-backed disarmament rather than trusting unilateral "closure" declarations — consistent with India's 1996 position that a test ban must be tied to a time-bound, non-discriminatory elimination of nuclear weapons [6]. India's deep-drilling expertise at Koyna [5] positions it to contribute scientific credibility to that regime.