Strong Fault Interaction in Double-Vergence Structure: Lessons From the 2022 Yuli Earthquake and the 2022 Chihshang Earthquake, Eastern Taiwan

TAKADA Youichiro

Department of Earth and Planetary Sciences

Jul. 31, 2025

ハの字型構造をなす2断層系における、断層のずれる向きと加わる力の関係（論文中の図9を改変）。各図の右側の断層で（a）逆断層型、（b）逆断層+左横ずれ型、（c）左横ずれ型の地震が起きた場合に、断層に加わる力の変化を示す。赤い領域は断層をずれやすくする力が、青い領域はずれにくくする力がかかっていることを意味する。

Press release (in Japanese)

Abstract
The Longitudinal Valley Fault (LVF) and the Central Range Fault (CRF) in eastern Taiwan consist of a head-to-head double-vergence structure hosting disastrous earthquakes. It was previously proposed that the fault slip on one of these faults suppresses the earthquake generation on the other. Nonetheless, the 2022 Chihshang earthquake (M_w 7.0) on the CRF occurred soon after the 2022 Yuli earthquake (M_w 6.7) on the LVF. Here, we provide a comprehensive framework of the fault interaction consistently explaining these contradictory findings. First, we estimated the coseismic slip distribution of the Yuli earthquake from Global Navigation Satellite System (GNSS) and L-band satellite interferograms. The results indicate almost pure reverse faulting. Second, with the estimated slip distribution, we calculated ……

Read the original article on Journal of Geophysical Research: Solid Earth

Article inforamation
Yuri Ishimaru, Youichiro Takada, Kuo-En Ching, Wu-Lung Chang, Strong Fault Interaction in Double-Vergence Structure: Lessons From the 2022 Yuli Earthquake and the 2022 Chihshang Earthquake, Eastern Taiwan, Journal of Geophysical Research: Solid Earth
DOI: 10.1029/2025JB031225