D.V. Ghica1 , M. Popa1
1National Data Centre of Romania, Magurele, Romania
Five nuclear tests (in 2006, 2009, 2013 and two in 2016) have been conducted by the Democratic People’s Republic of Korea (DPRK). The explosions were detected by the International Monitoring System (IMS) and located by the International Data Centre (IDC). The event magnitude estimates (mb from 4.1 to 5.1) indicate an increase of the released energy with each successive test. Seismic signals generated by the DPRK events detected by Romanian Seismic Network (RSN) and by other regional monitoring stations were used to compute event locations at the Romania National Data Centre (ROM_NDC). A comparison between solutions obtained at the ROM_NDC and the IDC is presented. Whereas all the IDC locations are better constrained as a consequence of IMS global coverage, a significant improvement in accuracy in ROM_NDC estimates is observed for the latter events, due to the increase in the number of RSN stations, as well as to the increase of the events’ magnitude. The shapes, amplitudes and spectral features of RSN signals were examined. A remarkable shape resemblance was observed for the signals generated by all five events, suggesting very similar explosive source types. Array processing techniques were applied for signal detection at the Romanian seismic array, BURAR, in order to estimate the slowness information and to specifically characterize signals from nuclear explosions.