| Summary: | 碩士 === 國立臺灣大學 === 土木工程學研究所 === 105 === Ground motion prediction equations (GMPEs), which are empirical models derived from past earthquake recordings, are often used to estimate ground motion intensity measure at a site. The site term in a GMPE can predict the site effect on ground motion. On the other hand, site effect can also be evaluated using ground response analyses if detailed sediment properties (e.g. shear wave velocity profile and stress-strain behavior) are available. Site amplification/deamplification can be expressed in terms of the ratio between the response spectra at surface and at downhole location, as well as transfer function.
In this study, using the ground motions recorded during the 2016 Meinong earthquake at the free field stations and vertical arrays operated by the Central Weather Bureau of Taiwan, the ground motion amplification (or deamplification) characteristics due to local site effect are evaluated. For free field ground motions, the source and path effects are removed by subtracting the general source and path terms (from a Taiwan-specifc GMPE) from the data, Then the trend of the remainders is identified and compared to the site terms from various GMPEs. For vertical arrays, the empirical transfer functions and amplification factors (ratio of intensity measure at surface to the same intensity measure at downhole location) are evaluated. The trends of these quantities are identified and compared to the theoretical values.
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