| 摘要(英) |
Taiwan is located at the collision and compression boundary between the Eurasian Plate and the Philippine Sea Plate, resulting in frequent seismic activity. Many of these small-scale seismic activities occur near faults that are not exposed on the surface, often explained by blind faults. Over time, the earthquake observation capabilities of the Central Weather Bureau′s seismic network have continuously improved. Since 2012, it has been upgraded to a 24-bit real-time earthquake observation system. This upgrade not only detects smaller seismic events that were previously undetectable but also significantly increases the number of observed small-scale earthquakes included in the earthquake catalog.
Due to the logarithmic correlation between earthquake magnitude and released energy, the rupture of small-scale earthquakes has a much smaller geometric impact compared to large-scale earthquakes. This study improves earthquake picking and location procedures to reduce uncertainties. By reselecting earthquake arrival times and employing a three-dimensional seismic velocity model for earthquake location and double-difference relocation, more accurate earthquake locations can be achieved.
Furthermore, modifications were made to the processing procedures of the second-order seismic moment method. Based on the aforementioned earthquake locations, earthquakes with magnitudes between 3 and 4 were selected as target events. Individual candidate empirical Green′s functions were selected under specified conditions for apparent source-time function calculations. Subsequently, the second-order seismic moment inversion was conducted using 32,760 combinations of strike (0° to 359°) and dip (0° to 90°), followed by error assessment and candidate empirical Green′s function filtering, to obtain the final rupture configuration of the target earthquake.
The obtained rupture configuration trends consistently with fault plane solutions of larger-scale earthquakes, while the proposed method allows for more detailed characterization of underground ruptures, facilitating further understanding of unknown subsurface structures in the future. |
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交通部中央氣象署網站
https://www.cwa.gov.tw
交通部中央氣象署－臺灣地震與地球物理資料管理系統網站
https://gdms.cwa.gov.tw
經濟部地質調查及礦業管理中心－臺灣活動斷層網站
https://fault.gsmma.gov.tw |
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