Physics-Based Ground Motion Simulations Using Kinematic and Dynamic Sources: A Case Study of the 2020 Mw 6.8 Elaziğ, Turkey Earthquake

Physics-based 3D numerical simulations for earthquake rupture dynamics and ground motion simulations capable of incorporating complex non-planar fault systems, rough surface topography and the heterogeneous structure of the media are playing an increasingly role in the study of the earthquake physics and earthquake engineering. Recent advances in high-performance computing allow deterministic 3D regional-scale broadband ground motion simulations to resolve frequencies up to 10 Hz (e.g., Heinecke et al., 2014; Zhang et al., 2019; Rodgers et al., 2020; Pitarka et al., 2021). Such simulations commonly assume kinematic or dynamic rupture sources. However, systematic analysis of the effects of kinematic and dynamic rupture sources on simulations is lacking. In this work, we first resolve the kinematic rupture model of the 2020 Mw 6.8 Elaziğ, Turkey earthquake from near-field seismic and InSAR observations. We then conduct dynamic rupture scenarios that aim to reproduce the slip characteristics of the preferred kinematic model and to assess its mechanical viability. The curved grid finite-difference method (CG-FDM) is adopted to implement dynamic rupture simulations on complex non-planar fault (Zhang Z. et al., 2014; Zhang W. et al., 2020). The heterogeneous initial stresses are generate from the projection of regional tectonic stress field and the modification of static stress drop calculated from the kinematic model. Ground motion using physics-based numerical methods that consider 3D complexities in topography, medium and source is simulated on the CGFDM3D-EQR platform (Wang et al., 2022). Our result indicates that dynamic source with heterogeneity is an important factor for physics-based seismic hazard assessment.

 

References

Heinecke, A., Breuer, A., Rettenberger, S., Bader, M., Gabriel, A. A., Pelties, C., ... & Dubey, P. (2014, November). Petascale high order dynamic rupture earthquake simulations on heterogeneous supercomputers. In SC'14: Proceedings of the International Conference for High Performance Computing, Networking, Storage and Analysis (pp. 3-14). IEEE.

Pitarka, A., Akinci, A., De Gori, P., & Buttinelli, M. (2022). Deterministic 3D Ground‐Motion Simulations (0–5 Hz) and Surface Topography Effects of the 30 October 2016 M w 6.5 Norcia, Italy, Earthquake. Bulletin of the Seismological Society of America, 112(1), 262-286.

Rodgers, A. J., Pitarka, A., Pankajakshan, R., Sjögreen, B., & Petersson, N. A. (2020). Regional‐Scale 3D ground‐motion simulations of Mw 7 earthquakes on the Hayward fault, northern California resolving frequencies 0–10 Hz and including site‐response corrections. Bulletin of the Seismological Society of America, 110(6), 2862-2881.

Wang, W., Zhang, Z., Zhang, W., Yu, H., Liu, Q., Zhang, W., & Chen, X. (2022). CGFDM3D‐EQR: A Platform for Rapid Response to Earthquake Disasters in 3D Complex Media. Seismological Research Letters, 93 (4): 2320-2334.

Zhang, W., Zhang, Z., Fu, H., Li, Z., & Chen, X. (2019). Importance of spatial resolution in ground motion simulations with 3‐D basins: An example using the Tangshan earthquake. Geophysical Research Letters, 46(21), 11915-11924.

Zhang, W., Zhang, Z., Li, M., & Chen, X. (2020). GPU implementation of curved-grid finite-difference modelling for non-planar rupture dynamics. Geophysical Journal International, 222(3), 2121-2135.

Zhang, Z., Zhang, W., & Chen, X. (2014). Three-dimensional curved grid finite-difference modelling for non-planar rupture dynamics. Geophysical Journal International, 199(2), 860-879.