中国东北及周边地区地壳横波衰减的成像研究

利用146个台站记录的中国地震年报及黑龙江、吉林、辽宁和内蒙古四省地震台网观测报告的6371个近震46652条横波振幅与周期资料,采用二维层析成像方法反演东北地区地壳介质品质因子Q₀空间分布图像.在绝大部分研究区都可达到2°×2°的分辨率.结果表明,东北及周边地区地壳介质品质因子Q₀平均值为323,其Q₀值分布及其所揭示的衰减变化特征与研究区的地表构造具有明显的相关性,如华北平原、松辽盆地和海拉尔平原等沉积层较厚的区域通常呈现为低Q₀值;而燕山、太行、兴蒙褶皱带等沉积层薄或基岩出露的区域则呈现为相对高的Q₀值.整个东北地区呈现高低衰减带相间分布.

Q0 tomography of S wave attenuation in Northeast China and adjacent regions

In this paper we have selected 46652 ML amplitude readings from 6371 events recorded by 146 stations as reported in the Annual Bulletin of Chinese Earthquakes(ABCE) and regional seismic network of Heilongjiang province,Jilin province,Liaoning province and Inner Mongolia province.A two-dimensional tomography method is adopted to find regional variation of crustal attenuation in Northeast China and its adjacent regions.We obtained an average Q0 value of 323 for the entire studied region with regional fluctuations ±200.In most of the study area a resolution of 2 degrees is attained.Regions with the highest attenuation(low Q0 values) are beneath Bohai Basin,and Songliao Plain and Hailaer Basin also have low Q0 values,as these areas have thick sediments and strong tectonic activity.The entire Northeast region shows a distribution pattern of alternating high and low attenuation.