Regional full seismic waveform inversion of crustal velocity
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Regional full seismic waveform inversion of crustal velocity structure in Qaidam Basin Biao Yang，Yanbin Wan Department of Geophysics, School of Earth and Space Sciences, Peking University, Beijing, 100871 China 2021. 04. 28
Contents 1 Tectonic Setting 2 Niche Genetic Algorithm 3 Application of NGA inversion in Qaidam Basin 4 Discussion References 2
1 Tectonic Setting Qaidam Basin Northern margin of the Tibetan Plateau Boundary The Altyn Tagh Range （ATR), the Qiman Tagh Thrust (QTT), the North Kunlun Thrust (NKT) and the Qilian Mountains Tectonic Surrounded by Tarim block, Qilian block , Bayan Har block. The concentration of tectonic stress results in strong tectonic activities in and around the basin (Huang Y et al. , 2017). Earthquake On November 10, 2008, an Mw 6. 3 earthquake occurred in the northern margin of Qaidam basin, recorded by 17 broadband temporary stations installed by the INDEPTH IV Project Stations Eastern basin H 02, H 13, D 04, H 01, H 05, H 06 Western basin A 01, A 02, H 16, A 05, h 18, H 19 Qilian orogen H 20, H 21, H 22, H 23 Figure 1. Tectonic setting and distributions of earthquakes and stations in the Qaidam Basin region. 3
2 Niching Genetic Algorithm Figure 2. Flow chart of niching genetic algorithm Figure 3. Test results of numerical simulation 4
3 Application of NGA inversion in Qaidam Basin Figure 4. The fitting of the observed seismic waveforms (red) of 7 stations in the eastern basin with theoretical seismic waveforms (blue) calculated by the final model
3 Application of NGA inversion in Qaidam Basin Figure 5. The fitting of the observed seismic waveforms (red) of 6 stations in the western basin with theoretical seismic waveforms (blue) calculated by the final model
3 Application of NGA inversion in Qaidam Basin Figure 6. The fitting of the observed seismic waveforms (red) of 4 stations in the Qilian orogen with theoretical seismic waveforms (blue) calculated by the final model
4 Discussion Figure 7. P-wave velocity structure in eastern basin, western basin and Qilian orogen
4 Discussion Model A Model B Figure 8. The fitting of the observed seismic waveforms (red) of 4 stations in the eastern basin with theoretical seismic waveforms (blue) calculated by the final model
4 Discussion B A Figure 9. Section of Qaidam Basin. Refer to Yin A , Dang Y Q , Zhang M , et al. (2008).
References Fuchs K , and Müller G. Computation of synthetic seismograms with the reflectivity method and comparison with observations. Geophys. J. Int. , 1971, 23(4), 417– 433. Huang Y , Chen Y Y , Wang Y B , et al. Amplification effect of seismic ground motion at the eastern part of Qaidam basin. China Earth. Eng. J. (in Chinese), 2017, 39(3), 534– 544. Mahfoud S W. Niching Methods for Genetic Algorithms. Ph. D. Dissertation. University of Illinois at Urbana. Champaign, 1995. Maurice R , Stacey D. Crustal and upper mantle structure of southernmost South America inferred from regional waveform inversion[J]. Journal of Geophysical Research Solid Earth, 2003, 108(B 1): -. Yin A , Dang Y Q , Zhang M , et al. Cenozoic tectonic evolution of the Qaidam basin and its surrounding regions (Part 3): Structural geology, sedimentation, and regional tectonic reconstruction[J]. Geological Society of America Bulletin, 2008, 120(7 -8): 847 -876. Zhang G M , Ma H S , Wang H , Wang X L. Boundaries between active tectonic blocks and strong earthquakes in the China mainland. Chinese J. Geophys. (in Chinese), 2005, 48(3), 602– 610. 11
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