Journal of the Earthquake Engineering Society of Korea (한국지진공학회논문집)

Earthquake Engineering Society of Korea (한국지진공학회)
권호 표지
DOI QR코드

DOI QR Code

Sensitivity Analysis of Finite Fault Model in Stochastic Ground Motion Simulations

추계학적 지진동 모사에서 유한단층 모델의 민감도 분석

  • Lee, Sang-Hyun (School of Earth and Environmental Science, Seoul National University) ;
  • Rhie, Junkee (School of Earth and Environmental Science, Seoul National University)
  • 이상현 (서울대학교 지구환경과학부) ;
  • 이준기 (서울대학교 지구환경과학부)
  • Received : 2023.12.14
  • Accepted : 2024.03.26
  • Published : 2024.05.01
Download PDF
⟨ Previous Next ⟩

Abstract

Recent earthquakes in Korea, like Gyeongju and Pohang, have highlighted the need for accurate seismic hazard assessment. The lack of substantial ground motion data necessitates stochastic simulation methods, traditionally used with a simplistic point-source assumption. However, as earthquake magnitude increases, the influence of finite faults grows, demanding the adoption of finite faults in simulations for accurate ground motion estimates. We analyzed variations in simulated ground motions with and without the finite fault method for earthquakes with magnitude (Mw) ranging from 5.0 to 7.0, comparing pseudo-spectral acceleration. We also studied how slip distribution and hypocenter location affect simulations for a virtual earthquake that mimics the Gyeongju earthquake with Mw 5.4. Our findings reveal that finite fault effects become significant at magnitudes above Mw 5.8, particularly at high frequencies. Notably, near the hypocenter, the virtual earthquake's ground motion significantly changes using a finite fault model, especially with heterogeneous slip distribution. Therefore, applying finite fault models is crucial for simulating ground motions of large earthquakes (Mw ≥ 5.8 magnitude). Moreover, for accurate simulations of actual earthquakes with complex rupture processes having strong localized slips, incorporating finite faults is essential even for more minor earthquakes.

Keywords

Acknowledgement

본 논문은 원자력안전위원회의 재원으로 한국원자력안전재단의 지원을 받아 수행한 원자력안전연구사업의 연구(RS-2023-00239569)의 일환으로 수행되었음.

References

  1. Park DH, Lee JM, Baag CE, Kim JK. Stochastic prediction of strong ground motion and attenuation equations in the southeastern Korean Peninsula. Journal of the Geological Society of Korea. 2001 Mar;37(1):21-30.
  2. Jo ND, Baag CE. Stochastic prediction of strong ground motions in southern Korea. Journal of the Earthquake Engineering Society of Korea. 2001 Aug;5(4):17-26.
  3. Junn JG, Jo ND, Baag CE. Stochastic prediction of strong ground motions in southern Korea. Geosciences Journal. 2002 Sep;6(3): 203-214.
  4. Jo ND, Baag CE. Estimation of spectrum decay parameter κ and stochastic prediction of strong ground motions in southeastern Korea. Journal of the Earthquake Engineering Society of Korea. 2003 Dec;7(6):59-70.
  5. Uchide T, Song SG. Fault rupture model of the 2016 Gyeongju, South Korea, earthquake and its implication for the underground fault system. Geophysical Research Letters. 2018;45:2257-2264.
  6. Song SG, Lee H. Static slip model of the 2017 Mw 5.4 Pohang, South Korea, earthquake constrained by the InSAR data. Seismological Research Letters. 2019;90:140-148.
  7. Cho E, Woo J, Rhie J, Kang T, Baag S. Rupture Process of the 2017 Mw 5.5 Pohang, South Korea, Earthquake via an Empirical Green's Function Method. Bulletin of the Seismological Society of America. 2023;113(2):592-603. DOI:10.1785/0120220161.
  8. Hartzell SH. Earthquake aftershocks as Green's functions. Geophysical Research Letters. 1978;5(1);1-4. DOI:10.1029/GL005i001p00001.
  9. Maechling PJ, Silva F, Callaghan S, Jordan TH. SCEC broadband platform: system architecture and software implementation. Seismological Research Letters. 2015;86:27-38. DOI:10.1785/0220140125.
  10. Choi H. Preliminary strong ground motion simulation at seismic stations within nuclear power plant sites in South Korea by a scenario earthquake on the causative fault of 2016 Gyeongju earthquake. Nuclear Engineering and Technology. 2022;54(7);2529-2539. DOI:10.1016/j.net.2022.01.017.
  11. Boore DM. Stochastic simulation of high-frequency ground motions based on seismological models of the radiated spectra. Bulletin of the Seismological Society of America. 1983;73:1865-1894.
  12. Beresnev IA, Atkinson GM. FINSIM-a FORTRAN program for simulating stochastic acceleration time histories from finite faults. Seismological Research Letters. 1998;69(1);27-32. DOI:10.1785/gssrl.69.1.27.
  13. Motazedian D, Atkinson GM. Stochastic finite-fault modeling based on a dynamic corner frequency. Bulletin of the Seismological Society of America. 2005;95(3):995-1010. DOI:10.1785/0120030207.
  14. Boore, DM. Comparing stochastic point-source and finite-source ground-motion simulations: SMSIM and EXSIM. Bulletin of the Seismological Society of America. 2009;99(6);3202-3216. DOI:10.1785/0120090056.
  15. Wells DL, Coppersmith KJ. New empirical relationships among magnitude, rupture length, rupture width, rupture area, and surface displacement. Bulletin of the Seismological Society of America. 1994;84(4):974-1002.