| Summary: | 碩士 === 中國文化大學 === 地學研究所地質組 === 101 === Earthquake is one of the major natural disasters caused massive destruction in the Taipei metropolitan area. Sanchiao fault is a western boundary fault of the Taipei basin located in northern Taiwan, close to the densely populated Taipei metropolitan area. Combined with the marine and terrestrial parts, the total fault length of Sanchiao fault could over 50 kilometers. For the past 400,000 years, the bedrock of Tertiary sedimentary basin continued to subside due to the activity of the Sanchiao fault, resulting the thickness of Quaternary sediments of the basin up to 700 meters in the northwest side. Displacement measured by GPS in northern Taiwan, on both sides of the Sanchiao fault, revealed up to 5-8 mm per year of movement. It may be reactivated in the future.
This study is based on the “RECIPE” for predicting strong ground motion proposed by Kojiro Iriura and Hiroe Miyake （2011）. The characteristic source parameters include: fault length, rupture area, seismic moment, the fault plane momentum slip, asperity and propagation pattern of rupture etc. Based on these assumptions in the characteristic source model, Sanchiao fault has been inferred to have the potential to produce an earthquake with moment magnitude (Mw) larger than 7.0. Three-dimensional seismic simulation using Spectral-Element Method (SEM), the 3D spectral-element method simulation results indicate that Peak Ground Acceleration (PGA) is significantly stronger along the fault trace. The basin effects play an important role when wave propagates in the Taipei basin which cause seismic wave amplified and prolong the shaking for a very long time.
In order to increase the universality and breadth of simulation study, we assumed multiple of possible earthquake scenarios. Among them, rupture direction from north to south of the situation is comparatively serious. Owing to the shock direction as well as the basin effect, Taipei basin has high PGA, especially on the northwest side. This clearly shows that it is closely related to the basin sediments. Through statistical analysis, the results of this numerical simulation will provide important earthquake disaster and earthquake engineering reference data.
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