Nearby fault interaction within the double-vergence suture in eastern Taiwan during the 2022 Chihshang earthquake sequence
Journal
Communications Earth and Environment
Journal Volume
4
Journal Issue
1
Date Issued
2023-12-01
Author(s)
Tang, Chi Hsien
Lin, Yunung Nina
Tung, Hsin
Lee, Shiann Jong
Hsu, Ya Ju
Kuo, Yu-Ting
Chen, Horng Yue
Abstract
Nearby faults interact through stress changes induced by fault slip and viscoelastic flow. The process is, however, often elusive and can be geometry-dependent and time-variant. Here, we combine geodetic and field observations to characterize the interaction of two head-to-head, conjugate faults in eastern Taiwan during the 2022 Chihshang earthquake sequence. We map the coseismic slip on the Central Range fault and dynamically-triggered shallow slip on the Longitudinal Valley fault, which has been creeping interseismically. Overlapping of seismic and aseismic slip suggests that the Longitudinal Valley fault is capable of hosting a variety of distinct slip behaviors. Moreover, substantial slip on the Central Range fault suppresses Coulomb stress on the Longitudinal Valley fault, and vice versa, resulting in seismic bursts in an out-of-phase pattern on the two faults as seen in the hundred-year historical records. Such fault interaction implies the need for time-dependent seismic hazard reassessment for the complex fault system.
SDGs
Type
journal article