Japan Geoscience Union Meeting 2025

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S (Solid Earth Sciences ) » S-CG Complex & General

[S-CG45] Science of slow-to-fast earthquakes

Tue. May 27, 2025 9:00 AM - 10:30 AM International Conference Room (IC) (International Conference Hall, Makuhari Messe)

convener:Aitaro Kato(Earthquake Research Institute, the University of Tokyo), Asuka Yamaguchi(Atomosphere and Ocean Research Institute, The University of Tokyo), Ryoko Nakata(Graduate School of Science, The University of Tokyo), Kurama Okubo(National Research Institute for Earth Science and Disaster Resilience), Chairperson:Takanori Matsuzawa(National Research Institute for Earth Science and Disaster Resilience), Daisuke Sato(japan agency for marine-earth science and technology)

9:45 AM - 10:00 AM

[SCG45-16] Triggered Slow Slip Event on an Inland Fault in the Hengchun Peninsula, Taiwan: Insights from Geodetic Data and Earthquake Sequence Simulation

*Shih-Han HSIAO1, Kuo-En Ching1, Ryosuke Ando2, Slawomir Jack Giletycz3, Wu-Lung CHANG3, Chien-Liang CHEN4 (1.National Cheng Kung University, 2.The University of Tokyo, 3.National Central University, 4.Geological Survey and Mining Management Agency, MOEA)

Keywords:slow-slip event, Hengchun fault, earthquake sequence simulation, earthquake potential

Our previous study proposed an ongoing triggered slow slip event (SSE) on the inland Hengchun fault (HCNF) following the 2006 ML 7.0 Pingtung offshore earthquake in Taiwan. This SSE was identified based on 3 precise leveling routes, 13 continuous GNSS stations, 37 campaign-mode GNSS stations, and a kinematic model covering the Hengchun Peninsula from 2002 to 2022. The surface velocity fields not only indicate that the trace of the HCNF should be shifted 1–2 km eastward but also reveal a time-varying velocity pattern that can be classified into five periods: (1) the interseismic period from 2002 to the 2006 Pingtung offshore earthquake; (2) the 2nd period after the earthquake to April 2010; (3) the 3rd period from April 2010 to 2013; (4) the 4th period from 2013 till 2016; (5) the 5th period from 2016 till 2022. The slip deficit rate distribution indicates that energy has accumulated along the entire HCNF, primarily in the northern shallow region. The slip rate is also predominantly distributed across the entire fault, with a migration from south to north. However, strain in part of the main accumulation area still remains. In period 5, the velocity pattern and slip area have begun to return to a pattern similar to period 2. To further investigate this SSE, we conduct a quasi-dynamic model that incorporates a simplified fault trace from our previous work, fault geometry from the Taiwan Earthquake Model, and initial stress conditions estimated after the 2006 earthquake to simulate the earthquake sequence on the HCNF.