Seismological Analysis of the Announced DPRK Nuclear Tests
Abstract
The Democratic People's Republic of Korea (DPRK) has announced 6 nuclear explosives tests (DPRK1 through DPRK6), starting in 2006 and ending in 2017. Each test was recorded on a number of common regional and teleseismic seismograph stations, making possible a wide variety of comparative studies for each event pair. In this talk we review the consensus conclusions that have been reached regarding event source parameters and highlight a few unresolved issues.
Waveform cross-correlation was used by a number of research groups to determine precise epicenters for DPRK1-6. Relative epicenters and absolute location of DPRK4 and DPRK6 based on ground displacement measured using InSAR place DPRK2-6 in Mt. Mantap (approximately lat=41.298°N, lon=129.078°E) and DPRK1 under a ridge approximately 2.5 km east southeast of Mt. Mantap. Small but statistically significant differences in published epicenters are most directly attributable to differences in model-based and empirically estimated body-phase slownesses. Event depths can be constrained using known topography, relative event locations, fit of seismogram coda envelopes, and simple assumptions about tunnel engineering. Results of this analysis find that DPRK1 through DPRK5 are over buried with respect to established nuclear-test-containment practice, and DPRK6 is at approximately standard scaled depth of burial. Even after applying constraints on event depths, uncertainties on explosion yield estimates remain approximately a factor of 2 because of unresolved differences in explosion-source models, particularly the effect of over burial and near-source rock properties on radiated seismic energy. Last, a number of unannounced seismic events have been located at and near Mt. Mantap. One event occurring 8.5 minutes after DPRK6 locates at Mt. Mantap and the magnitude is consistent with collapse of the DPRK6 cavity. Detection studies based on waveform cross-correlation have found additional events near the DPRK test site starting at least as early as 2013. These events are earthquake-like, as assessed by regional P/S discriminants, and they are located 3 km to 6 km north-northwest of Mt. Mantap. These events cluster in temporal swarms that tend to occur after nuclear tests, but direct connection with nuclear testing remains unresolved.LLNL-ABS-780804.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.S14B..06M
- Keywords:
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- 7219 Seismic monitoring and test-ban treaty verification;
- SEISMOLOGY;
- 7294 Seismic instruments and networks;
- SEISMOLOGY;
- 7299 General or miscellaneous;
- SEISMOLOGY