Abstract
Since the modern seismograph network by the Korea Meteorological Administration (KMA) had been operated from 1978, the largest earthquake (ML 5.8) occurred in Gyeongju, South Korea on 12 September 2016. ML 5.1 and 5.8 earthquakes occurred successively and damaged mostly old building structures around Gyeongju. Aftershocks continued to occur, clustering around the epicenters of the two events. Number of observed aftershocks with ML ≥ 0.1 was 3,376 from 12 September 2016 to 31 March 2017 and these aftershocks were located by manual procedure. Since the origin time of the ML 5.8 earthquake, 339 and 672 aftershocks (ML ≥ 0.1) occurred on 12 and 13 September 2016, respectively. The occurrence rate of aftershocks decreased exponentially with time after 16 September. It is observed that the seismicity of the 2016 Gyeongju earthquake and aftershock sequences is dominant in the Yangsan Fault System. The distribution of aftershocks is NNE-SSW direction along the Yangsan Fault System, which agrees with the fault plane solutions of main shock and foreshock showing the strike-slip faulting. These aftershocks concentrate within the epicentral distance of 5 km from main shock and the depth distribution of aftershocks is mainly around 11–15 km with vertical trends. With regard to the seismicity of the 2016 Gyeongju earthquake’s aftershocks the full catalog with ML ≥ 1.2 based on Mc is suggested in this study. Finally the distribution of aftershock sequence correlated to the focal mechanisms can provide specific seismicity in the Gyeongsang Basin.
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References
Bratt, S.R. and Bache, T.C., 1988, Locating events with a sparse network of regional arrays. Bulletin of the Seismological Society of America, 78, 780–798.
Bratt, S.R. and Nagy, W., 1991, The LocSAT program. Science Applications International Corporation, San Diego.
Chang, S.-J. and Baag, C.-E., 2006, Crustal structure in southern Korea from joint analysis of regional broadband waveforms and travel times. Bulletin of the Seismological Society of America, 96, 856–870.
Choi, H., Hong, T.-K., He, X., and Baag, C.-E., 2012, Seismic evidence for reverse activation of a paleo-rifting system in the East sea (Sea of Japan). Tectonophysics, 572–573, 123–133.
Chung, T.W. and Kim, W.H., 2000, Fault plane solutions for the June 26, 1997 Kyong-ju Earthquake. Journal of the Korean Geophysical Society, 3, 245–250. (in Korean with English abstract)
Dreger, D.S. and Helmberger, D.V., 1993, Determination of source parameters at regional distances with single station or sparse network data. Journal of Geophysical Research, 98, 8107–8125.
Han, M., Kim, K.-H., Son, M., and Kang, S.Y., 2017, Current microseismicity and generating faults in the Gyeongju area, southeastern Korea. Tectonophysics, 694, 414–423.
Hong, T.-K., 2010, Lg attenuation in a region with both continental and oceanic environments. Bulletin of the Seismological Society of America, 100, 851–858.
Hong, T.-K. and Choi, H., 2012, Seismological constraints on the collision belt between the North and South China blocks in the Yellow Sea. Tectonophysics, 570–571, 102–113.
Hong, T.-K., Baag, C.-E., Choi, H., and Sheen, D.-H., 2008, Regional seismic observations of the 9 October 2006 underground nuclear explosion in North Korea and the influence of crustal structure on regional phases. Journal of Geophysical Research, 113, B03305. DOI: 10.1029/2007JB004950
Hong, T.-K., Lee, J., Kim, W., Hahm, I.-K., Woo, N.C., and Park, S., 2017, The 12 September 2016 ML 5.8 mid-crustal earthquake in the Korean Peninsula and its seismic implications. Geophysical Research Letter. DOI: 10.1002/2017GL072899
Houng, S.E., Lee, J., and Hong, T.-K., 2016, Dynamic seismic response of a stable intraplate region to a megathrust earthquake. Tectonophysics, 689, 67–78.
Kennett, B.L.N. and Engdahl, E.R., 1991, Traveltimes for global earthquake location and phase identification. Geophysical Journal International, 105, 429–465.
Kim, K.-H., Kang, T.-S., Rhie, J., Kim, Y., Park, Y., Kang, S.Y., Han, M., Kim, J., Park, J., Kim, M., Kong, C., Heo, D., Lee, H., Park, E., Park, H., Lee, S.-J., Cho, S., Woo, J.-U., and Kim, J., 2016a, The 12 September 2016 Gyeongju earthquakes: 2. Temporary seismic network for monitoring aftershocks. Geosciences Journal, 20, 753–757.
Kim, Y., Rhie, J., Kang, T.-S., Kim, K.-H., Kim, M., and Lee, S.-J., 2016b, The 12 September 2016 Gyeongju earthquakes: 1. Observation and remaining questions. Geosciences Journal, 20, 747–752.
Kyung, J.B. and Lee, H.U., 1998, Intensity analysis of the 26 June 1997 Kyongju earthquake and its geological significance. The Journal of Engineering Geology, 8, 13–24. (in Korean with English abstract)
Kyung, J.B. and Lee, K., 2006, Active fault study of the Yangsan Fault System and Ulsan Fault System, southeastern part of the Korean Peninsula. Journal of the Korean Geophysical Society, 9, 219–230.
Lee, K. and Jin, Y.G., 1991, Segmentation of the Yangsan Fault System: geophysical studies on major faults in the Kyeongsang Basin. Journal of the Geological Society of Korea, 27, 434–449.
Lee, K. and Yang, W.-S., 2006, Historical seismicity of Korea. Bulletin of the Seismological Society of America, 96, 846–855.
Park, S.-C., Yang, H., Lee, D.K., Park, E.H., and Lee, W.-J., 2017, Did the 12 September 2016 Gyeongju, South Korea earthquake cause surface deformation? Geosciences Journal. DOI: 10.1007/s12303-017-0050-4
Um, S.H., Choi, H.I., Son, J.D., Oh, J.H., Kwak, Y.H., Shin, S.C., and Yun, H.S., 1983, Geological and geochemical studies on the Gyeongsang Supergroup in the Gyeongsang Basin. Korea Institute of Energy and Resources Bulletin, 36, 124. (in Korean with English abstract)
Utsu, T., Ogata, Y., and Matsu'ura, R.S., 1995, The centenary of the Omori formula for a decay law of aftershock activity. Journal of Physics of the Earth, 43, 1–33.
Wiemer, S. and Wyss, M., 2000, Minimum magnitude of completeness in earthquake catalogs: examples from Alaska, the Western United States, and Japan. Bulletin of the Seismological Society of America, 90, 859–869.
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Lee, J., Ryoo, Y., Park, S.C. et al. Seismicity of the 2016 ML 5.8 Gyeongju earthquake and aftershocks in South Korea. Geosci J 22, 433–444 (2018). https://doi.org/10.1007/s12303-017-0071-z
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DOI: https://doi.org/10.1007/s12303-017-0071-z