CAJ | 학술논문

大别-苏鲁造山带是中国大陆东部地区最重要的构造带之一。为了研究该地区上中下地壳的速度结构，选用国家数字地震台网和中国区域地震数据台网5省（山东、安徽、江苏、河南和湖北）连续两年（2009年5月—2011年5月）的垂直向地震记录，进行背景噪声互相关处理，叠加得到了台站对间的面波经验格林函数。采用多重滤波法提取了近4000条频散曲线，并反演得到了研究区10—25 s 的瑞雷波群速度分布结果。通过分析大别-苏鲁及其邻区的瑞雷波群速度结构图像，发现不同构造块体具有不同的瑞雷波群速度结构：①研究区内的郯庐断裂带及其周边地区包括鲁西地块和胶北地块上中下地壳均表现出明显的高速异常，可能是在拉张环境下岩浆岩上涌，导致高速、高密度的变质岩在地壳富集而形成；②苏鲁高压变质带的瑞雷波速度在10—25 s 周期内明显高于其它地区，其上中下地壳均表现出较高的群速度结构特征，认为苏鲁高压变质带至少延伸到下地壳，而大别造山带在10 s 时表现出高速特征，但在15—25 s 没有明显的高速特征，故无法从其结果中判断大别高压变质带的垂向延伸范围；③华北板块上中下地壳均表现为低速特征，体现了研究区内华北板块的大陆地壳减薄特征。
대별-소로조산대시중국대륙동부지구최중요적구조대지일。위료연구해지구상중하지각적속도결구，선용국가수자지진태망화중국구역지진수거태망5성（산동、안휘、강소、하남화호북）련속량년（2009년5월—2011년5월）적수직향지진기록，진행배경조성호상관처리，첩가득도료태참대간적면파경험격림함수。채용다중려파법제취료근4000조빈산곡선，병반연득도료연구구10—25 s 적서뢰파군속도분포결과。통과분석대별-소로급기린구적서뢰파군속도결구도상，발현불동구조괴체구유불동적서뢰파군속도결구：①연구구내적담려단렬대급기주변지구포괄로서지괴화효북지괴상중하지각균표현출명현적고속이상，가능시재랍장배경하암장암상용，도치고속、고밀도적변질암재지각부집이형성；②소로고압변질대적서뢰파속도재10—25 s 주기내명현고우기타지구，기상중하지각균표현출교고적군속도결구특정，인위소로고압변질대지소연신도하지각，이대별조산대재10 s 시표현출고속특정，단재15—25 s 몰유명현적고속특정，고무법종기결과중판단대별고압변질대적수향연신범위；③화북판괴상중하지각균표현위저속특정，체현료연구구내화북판괴적대륙지각감박특정。
The Dabie-Sulu orogenic belt is one of the major structural belts in eastern China.In order to obtain the S-wave velocity structure beneath the study area,we obtain Rayleigh wave empirical Green’s functions after cross-correlation and stacking between all possible station pairs using continuous ver-tical components seismograms recorded by Shandong,Anhui,Jiangsu,Henan and Hubei seismograph networks and China Broadband Digital Seismograph Network during May 2009 to May 2011.Then we extract nearly 4 000 Rayleigh wave group velocity dispersion curves by using the multiple filtering method, and group velocity maps at 10—25 s are reconstructed by inversion.The ambi-ent noise group velocity maps reveal that there are evident Rayleigh wave group velocity differences among different tectonic regions.① Tanlu fault and its sur-rounding areas including Luxi block and Jiaobei block exhibit higher velocity anomaly in the crust,which may be caused by the enrichment of the higher velocities and higher density metamorphite rocks in the crust in the extensional environment.② Rayleigh wave group velocity is apparently higher beneath the Sulu high-pressure metamorphic belt at the period of 10—25 s.Upper,middle and lower crust presents higher group velocity structure,which implies that the metamorphic belt extends probably down to the lower crust.On the other hand,it is difficult to define the range of the Dabie high-pressure metamorphic belt,because high velocity appears only at the period of 10—15 s.③ Lower velocity characteristic of upper,middle and lower crust beneath North China block indicates that the crust there is thinning.