Extensive and large nuclear weapons testing by North Korea resulted in long-term seismological activity

Concerning! Why the heck did North Korea need so many nuclear weapons tests? Since 2018, North Korea issued a moratorium on such testing.

"North Korea conducted six underground nuclear tests between 2006 and 2017 at the Punggye-ri test site.

The largest, final explosion was an equivalent magnitude 6.3 seismic event and deformed the mountaintop by about 3 meters.

Most studies have focused on characterizing the explosion events, but Fan et al. took a longer view. Their 17-year earthquake catalog identified about 1400 local earthquakes between 2008 and 2025, with a notable acceleration of events and magnitudes after the 2017 test. Delayed reactivation of shallow faults indicates that cumulative damage from the explosions has redistributed crustal stress in the region."

"... They show that these explosions have the potential to reactivate seismically quiet faults and produce earthquakes that may be difficult to distinguish from naturally occurring tectonic activity. ..."

From the abstract:

"Underground nuclear explosions typically produce short-lived seismic sequences that decay rapidly after testing ceases.

By contrast, seismicity near the Punggye-ri nuclear test site at Mt. Mantap in the Democratic People’s Republic of Korea has persisted and intensified for years after the final large-yield explosion in 2017, evolving from diffuse activity to spatially organized distribution along fault-controlled structures. Analysis of 17 years of continuous waveform data reveals a progressive increase in seismicity and delayed reactivation of shallow faults. Earthquakes cluster beneath asymmetric topography, indicating progressive stress redistribution within a critically stressed crustal volume. These observations challenge conventional expectations, showing that under specific geological conditions, underground nuclear testing can drive multiyear fault reactivation and extend posttest seismicity well beyond the immediate aftermath of an explosion."

In Science Journals | Science

Mt. Mantap nuclear testing triggered delayed seismicity via fault reactivation

Nuclear tests at Mt. Mantap have reactivated intraplate faults (no public access)

Distribution of earthquakes around North Korea’s Punggye-ri nuclear test site (Source)