文章基本信息

标题：Investigation for Strong Ground Shaking across the Taipei Basin during the MW 7.0 Eastern Taiwan Offshore Earthquake of 31 March 2002
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作者：Yi-Ling Huang ; Bor-Shouh Huang ; Kuo-Liang Wen 等
期刊名称：Terrestrial Atmospheric and Oceanic Sciences
印刷版ISSN：1017-0839
出版年度：2010
卷号：21
期号：3
页码：485-492
DOI：10.3319/TAO.2009.12.11.01(TH)
出版社：Chinese Geoscience Union
摘要：According to reconstructed ground motion snapshots of the northern Taiwan area during the M W 7.0 eastern Taiwan offshore earthquake of 31 March 2002, the composite effects indicated complicated wave propagation behavior in the ground motion of the Taipei basin. A major low frequency pulse arose after the S-wave with the duration of about 20 seconds was observed in northern Taiwan and dominated the radial direction. Observed waveforms of a low frequency pulse show amplification during the seismic wave across the Taipei basin from its eastern edge to western portion. This effect has been considered to be generated by an unusual source radiation, deep Moho reflection or basin bottom surface. In this study, recorded ground motions from a dense seismic network were analyzed using a frequency-wavenumber spectrum analysis for seismic wave propagation properties. We investigated temporal and spatial variations in strong shaking in different frequency bands. Results show that a simple pulse incident seismic wave strongly interacts with inside soft sediments and the surrounding topography of the Taipei basin which in turn extends its shaking duration. Evidence showed that seismic waves have been reflected back from its western boundary of basin with a dominant frequency near one Hz. Findings in this study have been rarely reported and may provide useful information to further constrain a three-dimensional numerical simulation for the basin response and velocity structure, and to predict ground motions of further large earthquakes.
关键词：Frequency wavenumber spectrum analysis; Converted waves; Reflection; Topography effect;