Surface Ruptures of the 2022 Guanshan–Chihshang Earthquake Sequence, Eastern Taiwan: Implications for Fault Behavior and Recurrence
Journal
Bulletin of the Seismological Society of America
Journal Volume
116
Journal Issue
1
Start Page
94
End Page
110
ISSN
0037-1106
1943-3573
Date Issued
2025-12-15
Author(s)
Lee, Zixin
Chiang, Chao-Jung
Lin, Li-Chieh J.
Chen, Lishiue
Jiang, You-Wei
Chao, Chuan-Min
Lin, Geng-Pei
Wang, I-Ting
Abstract
The 2022 Guanshan–Chihshang earthquake sequence in eastern Taiwan, comprising an ML 6.4 foreshock and an ML 6.8 mainshock, produced widespread surface ruptures along both flanks of the Longitudinal Valley. Integrating field observations, unmanned aerial vehicle-based photogrammetry, and high-resolution satellite imagery, we delineated rupture distribution and fault displacement along the Yuli and Chihshang faults. The Yuli fault, a section of the Central Range fault located on the western margin of the valley, accommodated significant left-lateral and reverse motion, with a maximum offset of about 2 m in Changliang. The Chihshang fault, a part of the Longitudinal Valley fault on the eastern margin, displayed a more distributed rupture. These rupture patterns correspond well with geodetic slip inversion models and support the interpretation of the west-dipping Central Range fault as the main seismogenic source. Strain partitioning may occur along the northern Yuli fault, as the fault in the Sanmin area has dominant sinistral motion and the Songpu branch shows mainly vertical motion. We interpret the Yuli fault as the principal surface expression of the Central Range fault system, which may be partially blind near its southern extent beneath the Chihshang fault. Comparison with the 1951 Hualien–Taitung earthquake sequence demonstrates repeated, nearly full rupture of the Yuli fault in both events, suggesting its maturity and repeated seismic behavior. The characteristic rupture of the Yuli fault also implies the segmentation of the Central Range fault system. This study improves constraints on surface rupture recurrence, fault segmentation, and fault kinematics in one of the most seismically active suture zones in the world.
Subjects
Chihshang
Taiwan
Antennas
Earthquakes
Fault slips
Geodetic satellites
Landforms
Photogrammetry
Unmanned aerial vehicles (UAV)
Aerial vehicle
Central ranges
Earthquake sequences
Fault displacement
Fault system
Field observations
High resolution satellite imagery
Main shock
Rupture distribution
Surface ruptures
earthquake magnitude
earthquake rupture
fault
foreshock
photogrammetry
satellite imagery
Satellite imagery
Publisher
Seismological Society of America (SSA)
Type
journal article