华北中北部地面运动衰减研究
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摘要
使用河北省数字地震遥测台网25个台的259条波形记录资料,采用三段几何衰减模型,通过反演得到华北中北部地区剪切波的衰减模型和介质的品质固子Q(f)值,Q(f)=420.8f~(0.384)。研究发现,华北中北部地区的Q值与广东地区很接近,而与其它地区差异较大。
Based on 259 horizontal-component digital seismograms recorded on 25 stations of HebeiTelemetered Network, the attenuation model and medium quality factor Q(f)=420. 8f~(0.384) of S-wave inCentral and North area of North China are obtained by using a trilinear geometrical spreading model andGA. It is shown that Q(f) in Central and North area of NorthChina is similar to that in Guangdong. Trilinear geometrical spreading model of NorthChina indicates that at a distance less than 50 km, cor-responding to attenuation of the direct wavel amplitudes decay slightly and more rapidly than 1/R. Be-tween 50 and 83 km, where the direct wave is joined by SmS, spectral amplitudes are approximately con-stant. Beyond 83 km, corresponding to the Lg phase, amplitudes decay at a rate that is consistent withR~(-0.5). The result shows that postcritical reflections from the Moho discontinuity play an important role indetermining the shape of the attenuation curve.
Based on 259 horizontal-component digital seismograms recorded on 25 stations of HebeiTelemetered Network, the attenuation model and medium quality factor Q(f)=420. 8f~(0.384) of S-wave inCentral and North area of North China are obtained by using a trilinear geometrical spreading model andGA. It is shown that Q(f) in Central and North area of NorthChina is similar to that in Guangdong. Trilinear geometrical spreading model of NorthChina indicates that at a distance less than 50 km, cor-responding to attenuation of the direct wavel amplitudes decay slightly and more rapidly than 1/R. Be-tween 50 and 83 km, where the direct wave is joined by SmS, spectral amplitudes are approximately con-stant. Beyond 83 km, corresponding to the Lg phase, amplitudes decay at a rate that is consistent withR~(-0.5). The result shows that postcritical reflections from the Moho discontinuity play an important role indetermining the shape of the attenuation curve.
引文
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[4] 黄玉龙,郑斯华,刘杰,等.广东地区地震衰减和场地响应的研究[J].地球物理学报,2003,46(1) :54-61
[5] Chung T W, Sato H. Attenuation of high-frequency p and s wave in the crust of southeastern South Korea [J]. Bull Seism Soc Amer, 2001, 91 (6) : 1867-1874
[6] Ordaz M. Source spectra and spectral attenuation of seismic waves from Mexican earthquake and evidence of amplification in the hill zone of Mexicao city[J]. Bull Seism Soc Amer, 1992, (82) : 24-43
[7] Singh S K, Ordaz M, Dattatrayam R S. A spectral analysis of the 21 May 1997 Jabalpur India, earthquake and estimation of Ground motion from future earthquakes in the India shield region[J]. Bull Seism Soc Amer, 1999, 89 (6) : 1620-1830
[8] Shi Jinghua, Kin W Y, Richard P G. The corner frequency and stress drops of intraplate earthquake in the northeastern United States[J]. Bull Seism Soc Amer, 1998, 88 (2) : 531-542
[2] Lam N T K, Wilson J L. Generation of synthetic earthquake accelerograms using seismological modeling: a review[J]. Journal of Earthquake Engineering, 2000, 4 (3) : 321-354
[3] Atkinson G M, Mereu R F. The shape of ground attenuation curves in Southeastern Canada [J]. Bull Seism Soc Amer, 1992, 82(5) : 2014-2031
[4] 黄玉龙,郑斯华,刘杰,等.广东地区地震衰减和场地响应的研究[J].地球物理学报,2003,46(1) :54-61
[5] Chung T W, Sato H. Attenuation of high-frequency p and s wave in the crust of southeastern South Korea [J]. Bull Seism Soc Amer, 2001, 91 (6) : 1867-1874
[6] Ordaz M. Source spectra and spectral attenuation of seismic waves from Mexican earthquake and evidence of amplification in the hill zone of Mexicao city[J]. Bull Seism Soc Amer, 1992, (82) : 24-43
[7] Singh S K, Ordaz M, Dattatrayam R S. A spectral analysis of the 21 May 1997 Jabalpur India, earthquake and estimation of Ground motion from future earthquakes in the India shield region[J]. Bull Seism Soc Amer, 1999, 89 (6) : 1620-1830
[8] Shi Jinghua, Kin W Y, Richard P G. The corner frequency and stress drops of intraplate earthquake in the northeastern United States[J]. Bull Seism Soc Amer, 1998, 88 (2) : 531-542
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