Abstract
The article presents the results of analyzing aftershock sequences initiated by underground nuclear tests conducted in North Korea in 2016 and 2017. Waveform cross-correlation and a multimaster method applied to phase association allowed us to find and analyze 91 aftershocks and group them into clusters associated with the underground explosions on September 9, 2016 (DPRK-5) and September 3, 2017 (DPRK-6). The duration, intensity, and sporadic nature of these two sequences indicate specific mechanisms of seismic energy release, which are probably related to the interaction of the destruction zones of DPRK-5 and DPRK-6 explosions and the collapse of their cavities with the gradual advance of the collapse columns to the free surface. The aftershock activity in 2021 suggested that the collapse process was not yet completed and predicted the occurrence of new aftershocks in the near future, which could end in the collapse column reaching the free surface. These assumptions were confirmed; during the preparation of this work, a strong aftershock with a magnitude of 3.85 was recorded on February 11, 2022, which, according to preliminary estimates, indicates the beginning of the final stage of the advance of the collapse column to the surface, the probability of which is discussed in this study.
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REFERENCES
Adushkin, V.V. and Spivak, A.A., Geomekhanika krupnomasshtabnykh vzryvov (Geomechanics of Large-Scale Explosions), Moscow: Nedra, 1993.
Adushkin, V.V., Kitov, I.O., Konstantinovskaya, N.L., Nepeina, K.S., Nesterkina, M.A., and Sanina, I.A., Detection of ultraweak signals on the Mikhnevo small-aperture seismic array by using cross-correlation of waveforms, Dokl. Earth Sci., 2015, vol. 460, pp. 189–191.
Adushkin, V.V., Bobrov, D.I., Kitov, I.O., Rozhkov, M.V., and Sanina, I.A., Remote detection of aftershock activity as a new method of seismic monitoring, Dokl. Earth Sci., 2017, vol. 473, pp. 303–307. https://doi.org/10.1134/S1028334X17030011
Adushkin, V.V., Kitov, I.O., and Sanina, I.A., Clusterization of aftershock activity of underground explosions in North Korea, Dokl. Earth Sci., 2021, vol. 501, pp. 955–958.https://doi.org/10.1134/S1028334X21110039
Bobrov, D., Kitov, I., and Zerbo, L., Perspectives of cross-correlation in seismic monitoring at the international data centre, Pure Appl. Geophys., 2014, vol. 171, nos. 3–5, pp. 439–468. https://doi.org/10.1007/s00024-012-0626-x
Bobrov, D., Kitov, I., and Rozhkov, M., Absolute and relative body wave magnitudes of five DPRK events as measured by the IDC, Science and Technology Conf., Vienna, 2017a, pp. T2.1–P3.
Bobrov, D., Kitov, I., and Rozhkov, M., Absolute and relative location at the IDC: Five DPRK events, in Science and Technology Conf., Vienna, 2017b, pp. T2.1–P2. https://doi.org/10.13140/RG.2.2.10085.29920
Coyne, J., Bobrov, D., Bormann, P., Duran, E., Grenard, P., Haralabus, G., Kitov, I., and Starovoit, Yu., CTBTO: Goals, networks, data analysis and data availability, New Manual of Seismological Observatory Practice 2 (NMSOP-2), Potsdam: Deutsches GeoForschungsZentrum, 2012, pp. 1–41. https://doi.org/10.2312/GFZ.NMSOP-2_ch15
Gibbons, S.J. and Ringdal, F., The detection of low-magnitude seismic events using array-based waveform correlation, Geophys. J. Int., 2006, vol. 165, no. 1, pp. 149–166. https://doi.org/10.1111/j.1365-246X.2006.02865.x
Gibbons, S.J., Pabian, F., Näsholm, S.P., Kværna, T., and Mykkeltveit, S., Accurate relative location estimates for the North Korean nuclear tests using empirical slowness corrections, Geophys. J. Int., 2016, vol. 208, no. 1, pp. 101–117.https://doi.org/10.1093/gji/ggw379
Kitov, I., Le Bras, R., Rozhkov, M., and Sanina, I., Discrimination of the DPRK underground explosions and their aftershocks using the P g/L g spectral amplitude ratio, Seismol. Res. Lett., 2018, vol. 89, no. 2B, p. 869. https://doi.org/10.1785/0220180082
Kitov, I., Bobrov, D., and Rozhkov, M., Seismic events found by waveform cross correlation after the announced underground nuclear tests conducted by the DPRK on 12.02.2013 and 06.01.2016. Aftershocks or hidden nuclear tests?, 2021. arXiv:2110.10071 [physics.geo-ph]
Rozhkov, M., Stachnik, J., Baker, B., Epiphansky, A., and Bobrov, D., Nuclear test depth determination with synthetic modelling: Global analysis from PNEs to DPRK-2016, Geophys. Res. Abstracts, 2016, vol. 18, p. EGU2016-6823.
Shebalin, P.N., Mathematical methods of analysis and forecast of earthquake aftershocks: The need to change the paradigm, Chebyshevskii Sb., 2018, vol. 19, no. 4, pp. 227–242. https://doi.org/10.22405/2226-8383-2018-19-4-227-242
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This work was funded by the Federal Budget, topic no. 122040400015-5.
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Translated by L. Mukhortova
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Kitov, I.O., Sanina, I.A. Analysis of Sequences of Aftershocks Initiated by Underground Nuclear Tests Conducted in North Korea on September 9, 2016 and September 3, 2017. Seism. Instr. 58, 567–580 (2022). https://doi.org/10.3103/S0747923922050097
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DOI: https://doi.org/10.3103/S0747923922050097