17:15 〜 18:45
[SSS04-P03] Microseismic analysis using a dense seismic array: identifying potential rupture in the Western Foothills, Taiwan
キーワード：Microseismic relocation, stress variations, dense seismic array
Taiwan is located at the convergence of the Eurasian Plate and the Philippine Sea Plate, characterized by the presence of fold-and-thrust belts developing at the deformation front of the orogenic belt. In the 20th century, southwestern Taiwan experienced several medium to large earthquakes, posing a significant seismic risk due to its dense population. The Chukou fault is a significant boundary between the fold-and-thrust belt and the western plain, contributing to substantial seismic activity in the region. Due to the interaction between complex fault systems with distinct movements, investigating the seismogenic structures in this area is crucial for disaster prevention. To comprehend the characteristics of fault systems in southwestern Taiwan, a dense seismic array was deployed along the Western Foothills to exam the seismogenic structures and regional stress distribution.
The earthquakes were relocated using the HypoDD method and grouped through the DBSCAN algorithm to further analyze for focal mechanism and regional stress fields. The analysis revealed rupture patterns of oblique thrust faults and strike-slip faults, indicating the influence of highly fractured upper crustal structures. These structures induce time-varying dynamic stress fields, triggering pre-existing faults along diverse fault systems. This study proposes that the phenomenon could reveal undiscovered seismogenic structures in the frontier area of the Western Foothills. Further integration with geological and tomographic results could provide insights into the distribution of fault structures and areas with potential high seismic risk in the future. This integrated approach contributes to a comprehensive understanding of seismic hazards in southwestern Taiwan.
The earthquakes were relocated using the HypoDD method and grouped through the DBSCAN algorithm to further analyze for focal mechanism and regional stress fields. The analysis revealed rupture patterns of oblique thrust faults and strike-slip faults, indicating the influence of highly fractured upper crustal structures. These structures induce time-varying dynamic stress fields, triggering pre-existing faults along diverse fault systems. This study proposes that the phenomenon could reveal undiscovered seismogenic structures in the frontier area of the Western Foothills. Further integration with geological and tomographic results could provide insights into the distribution of fault structures and areas with potential high seismic risk in the future. This integrated approach contributes to a comprehensive understanding of seismic hazards in southwestern Taiwan.