NORSAR has recorded a small seismic event in North Korea in the region where underground nuclear test explosions have taken place in recent times.
The event has a magnitude between 3.2 and 3.4. Preliminary analysis of the seismic signals indicates more similarity with signals generated by tectonic sources than with the signals generated by the declared nuclear explosions. A likely explanation of the signals is an aftershock or rock failure resulting from the previous large underground nuclear test carried out on September 3, 2017. Further analysis of the signals will be carried out.