Mechanism of Postseismic Deformation of Ground Surface Following the 1999 Chi-Chi Earthquake, Taiwan
详细信息
- 责任者：Fu Zhen (Chinese Academy of Geological Sciences ; Beijing 100037 ; China) ; Zhang Haiming
- 刊名：Chinese Journal of Geophysics
- 出版年：2013
- 卷期：56(8)
- 关键词：集集地震1999 ; Chi-Chi earthquake 1999 ; 力学模型 ; mechanical models ; 台湾 ; Taiwan Province
- 页码：p.2681-2689
- 图表：6 illus., 31 refs.
- 分类号：0500
- issnNo：ISSN0001-5733
- isbnNo：CN11-2074/P
摘要
GPS measurements of 450 days after the 1999 Chi-Chi,Taiwan,earthquake revealed large postseismic displacement from dozens to hundreds of millimeters.Two possible mechanisms responsible for the postseismic deformation of the surface are the viscous relaxation of the lower crust and the afterslip caused by the aseismic creep of the earthquake fault.In this study,the finite element method(LDDA) for the viscoelastic contact problems is used to simulate the postseismic deformation process of the 1999 Chi-Chi earthquake with the GPS data as constraints.And the two possible mechanisms,viscous relaxation and afterslip,are discussed.The results indicate that the postseismic deformation observed by GPS can be well explained by the viscous relaxation mechanism.The viscosity of the lower crust below the Taiwan area is estimated as 1017 Pa·s by the trial and error method.The effect of afterslip mechanism on the postseismic deformation of the Chi-Chi earthquake is investigated by the numerical method with rate-and-state dependent frictional law.The results suggest that the GPS data cannot be explained by the afterslip mechanism alone,which only affects the postseismic deformation in the early 50 days after the mainshock.These studies will throw light on understanding the mechanism of the postseismic deformation of the 1999 Chi-Chi,Taiwan,earthquake.
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