This study investigates the interaction between two head-to-head, conjugate faults in eastern Taiwan during the 2022 Chihshang earthquake sequence using geodetic and field observations. The results show coseismic slip on the Central Range fault and dynamically triggered shallow slip on the Longitudinal Valley fault. The overlapping seismic and aseismic slip indicates diverse slip behaviors on the Longitudinal Valley fault. Furthermore, the study reveals that substantial slip on one fault suppresses Coulomb stress on the other, resulting in an out-of-phase pattern of seismic bursts. This fault interaction highlights the need for time-dependent seismic hazard reassessment for complex fault systems.

Chi-Hsien Tang, Yunung Nina Lin, Hsin Tung, Yu Wang, Shiann-Jong Lee, Ya-Ju Hsu, J. Bruce H. Shyu, Yu-Ting Kuo, Horng-Yue Chen