A Study Of Ground Motion Attenuation Characteristics And Spatial Correlation In Chi-Chi Earthquake

China is one of the countries where earthquake happens most frequently in the world. With the rapid development of the economy and the increase of wealth, threats posed by earthquakes to the people's lives and properties have been doubled accordingly. The seismic event is a synthesis full of uncertainties; while should the seismic mechanism and the spatial characteristics of ground motion be fully understood, it will lead to more scientifically sound and rational designs of large span bridges, nuclear power plants, pipelines and other large spatial lifeline structures. Besides, researches of spatial characteristics of ground motion are of great significance for catastrophe insurance, seismic hazard analysis, loss assessment, disaster relief and reconstruction, etc.Based on theories of earthquake engineering and seismic design, the ground motion data of Chi-Chi earthquake happened in Taiwan, 1999, are used to investigate the ground motion characteristics, considering the stochastic uncertainty and site conditions, by applying statistical and probabilistic methods. The objective of this study is to obtain the general rules of spatial characteristics of Chi-Chi earthquake ground motions and a seismic excitation model which considers the spatially correlated non-uniform feature of ground motions. Detailed researches are summarized as follows:1. Spatial statistical properties of peak ground motion parameters, pseudo-acceleration spectrum and vertical ground motion are studied; the factors such as magnitude, distance, site conditions that affecting the spatial distribution of ground motion parameters are analyzed.2. Based on least squares method, attenuation models of peak ground motion parameters and the pseudo-acceleration response spectrum are established; the uncertainty component that represents the characteristics of seismic source (Inter-event variability) and that represents the characteristics of sites (Intra-event variability) in the attenuation models are discussed.3. Correction to the ground motion attenuation models, considering the site conditions, is put forward; a spatial correlation model is proposed using the corrected results.The researches in this thesis involved many aspects of earthquake engineering. To a certain extent, it enhances our understanding of peak ground motion, spatial distribution of response spectra and seismic stochastic uncertainties. This work provides instructive references to the establishment of models on the spatially correlated non-uniform ground motion input for structure design and seismic hazard analysis.