摘要
对丽江大震后地震现场４个ＰＤＲ－２数字化地震台记录的３０个中小余震的垂直分量Ｐ波和水平分量Ｓ尾波进行振幅谱分析，表明观测振幅谱形状依赖于观测场地。利用频谱比方法，将丽江地震台视为基岩场地，宾馆台和白沙台为沉积层场地，玉龙变电站台为风化层场地，求得沉积层和风化层场地相对基岩场地的放大或吸收量级。衰减系数ｔ值的分析研究表明各场地地震波衰减与震源距相关微弱，但能灵敏反映传播路径的变化，表明衰减系数ｔ主要反映近场地下介质对地震波的散射效应。
nalyses of amplitude spectra of P wave and S coda of 30 moderate-small earthquakes recorded by 4 POR-2 digitized seismic stations set up in seismic area after Lijiang earthquake were made, which indicates that the shapes of observed amplitude spectra depend on the observing sites. Taking the Lijiang station as bedrock site, Hotel station and Baisha station as deposit sites, Yulong Transformer station as weathered site, the magnitude order of amplification or absorption of deposit and weathered sites relative to bedrock site is obtained by method of ratio of frequency spectra. The analyses of attenuation constant t* indicate that the attenuation of seismic wave is less related with source distance, but sensitive to variation of transmission path, showing that the attenuation constant mainly reflects scattering effect of underground media to seismic wave in near site.
出处
《地震研究》
CSCD
北大核心
1998年第2期115-121,共7页
Journal of Seismological Research
关键词
余震
波谱分析
地震波衰减
丽江地震
地震场
aftershock, spectral analysis, seismic wave attenuation, Lijiang earthquake
