Unzipping of the Conjugate Fault System During the 2024 Mw7.4 Hualien Earthquake

IF 4.6 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geophysical Research Letters Pub Date : 2025-06-30 DOI:10.1029/2025GL115218

Liuwei Xu, Lingsen Meng, Wenbin Xu, Yen-Yu Lin, Jianghui Geng, Saeed Mohanna, Grant Kawamoto

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Abstract

On 2 April 2024, a Mw7.4 earthquake struck Taiwan's eastern coast near Hualien City. The fault responsible for the mainshock remained under debate due to the region's complex plate boundary system and intricate fault interactions. To determine the fault plane and resolve the rupture process, we analyzed local and teleseismic waveform recordings, along with near-field and satellite geodetic data. We employed Slowness-Enhanced Back-Projection and Finite Fault Inversion techniques across seismic and geodetic data sets. Our analysis revealed that the rupture propagated on the east-dipping Longitudinal Valley Fault (LVF) and its west-dipping conjugate fault. The rupture started on the LVF and reached the conjugate fault at ∼8 s, after which slip occurred simultaneously on both faults. The aftershock distribution validated the fault geometry. The 2024 mainshock demonstrated the seismic potential of the LVF and its role in accommodating the thrust component of strain accumulation from the plate collision near Hualien.

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2024年花莲7.4级地震共轭断层系统的解压缩

2024年4月2日，台湾东部沿海花莲市附近发生里氏7.4级地震。由于该地区复杂的板块边界系统和复杂的断层相互作用，导致主震的断层仍然存在争议。为了确定断裂面并解决破裂过程，我们分析了本地和远震波形记录，以及近场和卫星大地测量数据。我们在地震和大地测量数据集上使用了慢度增强反投影和有限断层反演技术。分析结果表明，此次断裂是在东倾的纵向山谷断层及其西倾的共轭断层上传播的。破裂开始于LVF，并在约8 s到达共轭断层，之后两个断层同时发生滑动。余震分布验证了断层的几何形状。2024年主震显示了LVF的地震潜力及其在容纳花莲附近板块碰撞应变积累的逆冲分量中的作用。

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来源期刊

Geophysical Research Letters 地学-地球科学综合

CiteScore

9.00

自引率

9.60%

发文量

1588

审稿时长

2.2 months

期刊介绍： Geophysical Research Letters (GRL) publishes high-impact, innovative, and timely research on major scientific advances in all the major geoscience disciplines. Papers are communications-length articles and should have broad and immediate implications in their discipline or across the geosciences. GRLmaintains the fastest turn-around of all high-impact publications in the geosciences and works closely with authors to ensure broad visibility of top papers.