[S-SS09] Strong Ground Motion and Earthquake Disaster

[SSS09-P14] Broadband ground-motion simulation of the 2022 Taitung Guanshan and Chishang, Taiwan, earthquakes

*Chun-Te Chen¹, Yin-Tung Yen¹ (1.Sinotech Engineering Consultants, Inc., Taipei, Taiwan)

Keywords:Taitung earthquake, spectral-element method, stochastic finite-fault method, earthquake scenario

On September 17^th, 2022, an earthquake of moment magnitude M_w 6.6 occurred in Guanshan Township, Taitung County, south-eastern Taiwan. After 17 hours, another stronger earthquake with moment magnitude M_w 7.1 struck the Chishang Township slightly northerly. The strong motions induced the train to derail and buildings and serval bridges to collapse. To better understand the uncertainty of the ground-motion simulation technique and the characteristic of ground motions, we implemented the numerical model of broadband waveforms for these earthquakes. The low-frequency waveforms were reproduced using the spectral-element method, while the high-frequency waveforms were generated using the stochastic finite-fault method. The broadband waveforms were then superposed using a matched filter. We considered waveform simulation of complex rupture processes and simple source models to clarify their differences. The uncertainty between the two models was quantified by analyzing the residuals of ground motions. The results show a comparable pattern of shaking distribution for validating ground motion simulation procedures to enhance the potential for further mitigating future earthquake impact using earthquake scenario simulations.