Coseismic deformation and seismogenic structure of the 2024 Hualien Earthquake measured by InSAR and GNSS

Abstract

On April 3, 2024, an M 7.3 earthquake occurred in the offshore area of Hualien County, Taiwan, China. The seismogenic structure at the epicentral location was highly complex, and studying this earthquake is paramount for understanding regional fault activity. In this study, we employed ascending and descending orbit Sentinel-1 Synthetic Aperture Radar (SAR) data and utilized differential interferometry (InSAR) technique to obtain the co-seismic deformation field of this event. The line-of-sight deformation field revealed that the main deformation caused by this earthquake was predominantly uplift, with maximum uplift values of approximately 38.8 cm and 46.1 cm for the ascending and descending orbits, respectively. By integrating the three-dimensional GNSS coseismic deformation field, we identified the seismogenic fault located in the offshore thrust zone east of Hualien, trending towards the northwest. The fault geometry parameters, obtained through the inversion of an elastic half-space homogeneous model, indicated an optimal fault strike of 196°, a dip angle of 30.9°, and an average strike-slip of 0.4 m and dip-slip of -2.6 m. This suggests that the predominant motion along the seismogenic fault is thrusting. The distribution of post-seismic Coulomb stress changes revealed that aftershocks mainly occurred in stress-loaded regions. However, stress loading was observed along the northern segment of the Longitudinal Valley Fault, with fewer aftershocks. This highlights the importance of closely monitoring the seismic hazard associated with this fault segment.

Keywords

2024 Hualien earthquake / InSAR / Co-seismic deformation / Seismogenic structure / Coulomb stress change

CRediT authorship contribution statement

Jiangtao Qiu: Writing - review & editing, Writing - original draft, Visualization, Validation, Funding acquisition, Data curation. Lingyun Ji: Software, Conceptualization. Liangyu Zhu: Supervision, Methodology, Formal analysis. Yongsheng Li: Writing - review & editing, Visualization, Supervision, Resources, Methodology. Chuanjin Liu: Methodology, Formal analysis, Data curation.

Declaration of competing interest

The authors declare that there are no conflicts of interest regarding the publication of this article titled "Coseismic deformation and seismogenic structure of the 2024 Hualien Earthquake measured by InSAR and GNSS". The research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. All authors have contributed equally to this work and have no personal or financial relationship with other people or organizations that might potentially influence or bias the content of this article.

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We hereby agree to the following terms regarding the submission of our manuscript titled "Coseismic deformation and seismogenic structure of the 2024 Hualien Earthquake measured by InSAR and GNSS" for consideration for publication in the Journal of Earthquake Research Advances:

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