[S-GD01] Geodetic Advances in Crustal Dynamics and Environmental Change for Taiwan and Neighboring Regions

[SGD01-03] Creep Rate Changes of Shallow Active Faults in Southwestern Taiwan Based on InSAR and GNSS analysis

*Lishiue Chen¹, Ray Y Chuang², Takeshi Sagiya^3,1 (1.Graduate School of Environmental Studies, Nagoya University, 2.Department of Geography, National Taiwan University, 3.Disaster Mitigation Research Center, Nagoya University)

Keywords:fault creep, synthetic aperture radar, Southwestern Taiwan

The creeping behavior of active faults plays a critical role for evaluating fault activities and seismic risks. Such creeping faults not only pose a risk to infrastructure but also significantly impact the assessment of regional seismic hazard potential. Southwestern Taiwan, situated along an active orogenic belt, has experienced significant surface deformation, posing risks to the lives and property of millions of residents in Tainan and Kaohsiung. Notably, two major seismic events—the 2010 ML 6.4 Jiashian earthquake and the 2016 ML 6.6 Meinong earthquake—have likely altered the deformation patterns. This raises critical questions about how surface deformation evolves between those seismic events.
This study employed the SBAS-InSAR technique to analyze L-band SAR datasets from ALOS (2007–2010) and ALOS-2 (2015–2022), focusing on regions characterized by agricultural activities and dense vegetation. Interseismic velocity fields and the coseismic deformation map of the 2016 Meinong earthquake were generated. GNSS and leveling datasets were further incorporated to validate the InSAR-derived velocity fields. Our findings identified 15 velocity boundaries between the Hsinhua Fault and the Pingtung Plain, indicating active structural creep changes in different periods. These observations highlight the importance of detailed geodetic monitoring to refine our understanding of seismic hazards in Southwestern Taiwan.