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Spatiotemporal Analysis of an Earthquake Swarm beneath the Dayoukeng, Tatun Volcano Group, Taiwan

Min-Hung Shih1, 3,  Ya-Chuan Lai1, 3, Cheng-Horng Lin1, 2, 3,   Hsiao-Fen Lee1, 3

  • Affiliations: 1National Center for Research on Earthquake Engineering, National Applied Research Laboratories, Taipei 10668, Taiwan.  2Taiwan Volcano Observatory at Tatun, Taipei 11292, Taiwan.  3Institute of Earth Sciences, Academia Sinica, Taipei 11529, Taiwan. 

  • Presentation type: Poster

  • Presentation time: Thursday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 124

  • Programme No: 2.1.34

  • Theme 2 > Session 1

Abstract

The Dayoukeng fumarole, situated within the Tatun Volcano Group (TVG) in northern Taiwan, represents one of the most active hydrothermal systems in the region, characterized by vigorous fumaroles, hot springs, and phreatic deposits. The persistent seismicity observed beneath this area over past decades suggests ongoing hydrothermal processes. Its proximity to the densely populated Taipei Metropolitan Area (population > 7 million) underscores the importance of comprehensive volcanic monitoring. To enhance our understanding of the subsurface processes, we deployed a high-density seismic array of 50 Fairfield Nodal ZLand 3C nodes around Dayoukeng, with inter-station spacing of 50-200 meters. This array recorded a significant earthquake swarm on December 21, 2021, initially comprising approximately 50 events detected by the Tatun Volcano Observatory at Taiwan (TVO) permanent broadband network. Analysis of the dense array data revealed additional micro-earthquakes within the swarm sequence. The detailed spatiotemporal distribution of seismicity and focal mechanism solutions illuminate the complex interaction between hydrothermal activity and structural features beneath Dayoukeng. These findings advance our understanding of the volcanic system's current state and contribute to volcanic hazard assessment for the Taipei Metropolitan Area.