Discrimination and Relocation of The 2013 North Korea Underground Nuclear Test: A New Contribution

Abstract:

We successfully give contribution in discriminating the 2013 North Korea underground nuclear test from natural earthquakes by using analysis of ratio of seismic energy and seismic moment (Ɵ) and analysis of the rupture duration. We used the waveform data of the shallow seismic event which occurred in the region of North Korea mainland and vicinity in last decade. We conclude that this earthquake was a shallow seismic event with explosion characteristics and can be discriminated from a natural or tectonic earthquake. The 2013 North Korea test earthquake had 2.817822 x 1019 N.m of the seismic moment and 7.652314 x 1014 N.m of radiated seismic energy and -4.56 of the Ɵ value. The equivalent Ɵ value with the two previous nuclear events and differences with natural earthquakes was considered as an implication of the explosion event. The rupture duration value of this event was 11.13 s. The very low value of the rupture duration from the three nuclear tests event shows us the characteristic of the explosion. We also give contribution in determining the high precision location of the 2013 nuclear test earthquake using relocation algorithm of Modified Joint Hypocenter Determination (MJHD) and double difference using IMS CTBTO, BMKG, regional and global seismic stations respectively. We also compared the relative location results with absolute location method of Simulated Annealing (SA). Results of the all relocation method in this study show the locations with distance less than 7 km from the Punggye-ri nuclear test facility. A result was compared with the relocation results by all possible combination of seismic phase data and stations and by previous researchers and analyzed using topographic data satellite imagery. We proposed that the northwest of the Punggye-ri facility (named “A” location) in coordinate 129.04 E and 41.29 N with elevation around 2050-2150 meter is the high possibility location of the 2013 North Korea underground nuclear test.