Based on recent studies suggesting that Rayleigh waves are observable in microtremor ground motions, an improved procedure is proposed to estimate a natural period of a site using amplitude ratios between horizontal and vertical motion of the microtremors. The procedure is to make the best use of not only peaks but also troughs in a spectral amplitude ratio. Using microtremor data measured at all junior high schools in 23 wards of Tokyo, the proposed procedure is applied to a period-mapping of the area and compared with an existing map to a satisfactory level of accuracy, demonstrating its practicality.
|Number of pages||10|
|Journal||Doboku Gakkai Rombun-Hokokushu/Proceedings of the Japan Society of Civil Engineers|
|Issue number||489 pt 1-27|
|Publication status||Published - 1994 Jan 1|
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