Seismic detection of strong ground motions by MW5.6 North Korean nuclear explosion

Abstract

The North Korean nuclear explosion test site in Punggye-ri is located in a seismically quiescent region on a stable Precambrian basement. The 3 September 2017 MW5.6 North Korean underground nuclear explosion (UNE) test produced unprecedented strong ground motions. The peak ground accelerations might reach tens to hundreds m/s2 on the surface of the UNE test site, decaying exponentially with distance. Ten shallow events with magnitudes greater than or equal to ML2.5 and source depths less than 3 km followed the 2017 UNE for 5 months in an area with a radius of 15 km from the UNE where strong ground shaking was experienced. The largest event with MW3.7 occurred 20 days after the 2017 UNE test at shallow depths less than 3 km. Its moment tensor solution indicates a combined source behavior with comparable strengths of double-couple and compensated linear vector dipole (CLVD) components, suggesting an unusual event different from typical natural earthquakes in the Korean Peninsula. The clustered shallow seismic events appeared to have occurred in damaged media that were effectively perturbed by the strong ground motions of the UNE.

Elastogravity Waves and Dynamic Ground Motions in the Korean Peninsula Generated by the March 11, 2011MW9.0 Tohoku‐Oki Megathrust Earthquake

“…The observation suggests that the seismic damages may be more dependent on PGA than PGV. It is noteworthy that the seismic intensities (seismic damages) in the Korean Peninsula could be well determined based on PGAs (Hong et al., 2019; Park & Hong, 2017). However, the long‐period ground motions produced by the Tohoku‐Oki earthquake may affect high‐rize buildings and structures of which natural frequencies are low.…”