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摘要
Both Lg-wave attenuation and site responses are determined in the eastern China region, the region ranges from 26 degrees N to 33 degrees N and 117 degrees E to 124 degrees E. We analyze over 1360 three-component seismograms from 92 local and regional earthquakes, the seismograms are recorded in the distance range of 100-600 km. The earthquakes occurred between 2002 and 2012 in the region and varied in magnitude between 2.0 and 4.7 (M-L). A combined inversion method, which can simultaneously estimate attenuation and site response from seismic spectral ratios, is implemented in the study. Modeling errors are determined using a delete-j jackknife resampling technique. Fourier spectral amplitudes are measured from Lg phases windowed between the group velocity limits 2.6 and 3.6 km/s. The inversion are performed in a frequency range of 1-6 Hz with an interval of 0.2 Hz, The frequency-dependent quality factor is modeled in the form of Q = Q(0)f(eta). The eastern China region displays high Q(0) and a weaker frequency dependence characterized by the functions Q = 335 +/- 16f(0.45 +/- 0.02), Q = 411 +/- 21f(0.26 +/- 0.01), and Q = 432 +/- 26f(0.24 +/- 0.01) for vertical, north-south, and east-west components, respectively, the values are similar to the average for other stable regions of the globe. Site responses from 32 stations are estimated in the region, most stations do not show obvious amplification. The site responses are mainly smooth, flat, and less than 5 in the frequency range of 1-6 Hz.
- 出版日期2014-6
- 单位浙江省地震局
