摘要
利用渤海湾及其邻区的10多条地震测深剖面段观测资料,对部分剖面进行二维射线追踪、走时拟合及合成地震图计算,获得了本区地壳上地幔速度结构.结果表明, 地壳上地幔结构在纵向和横向上具有明显的不均匀性.在冀中坳陷东北部的永清附近、黄骅坳陷的渤海湾和济阳坳陷的垦利附近存在上地幔隆起,隆起处的地壳厚度分别约为31, 28和29 km.根据地震波动力学及运动学特征和二维速度结构中的地震界面与速度等值线起伏变化,推测该区有3条地壳深断裂带,在地壳深断裂带一侧或两侧上地壳存在5.90～6.10 km/s的低速层(体).
Observational data from some of the 10-odd deep seismic sounding (DSS) profiles in Bohai Bay and its adjacent areas were processed with the methods of two-dimensional (2-D) ray tracing, travel-time fitting and synthetic seismogram. The crust and upper-mantle velocity structure model in this area was built. The results show that the crust and upper mantle structures present obvious lateral and vertical inhomogeneity. The upper mantle uplifts near Yongqing of northeast Jizhong depression, in Bohai Bay of Huanghua depression and near Kenli of Jiyang depression, where crustal depths are about 31 km, 28 km and 29 km, respectively. According to the dynamic and kinetic characteristics of seismic waves as well as the seismic interfaces and velocity contour undulation in the 2-D velocity structure model, three deep crustal fault zones are inferred in the area. Low velocity (5.90～6.10 km/s) layers (bodies) exist on one or two sides of these deep crustal fault zones.
出处
《地震学报》
CSCD
北大核心
2002年第4期428-435,共8页
Acta Seismologica Sinica
基金
国家重点基础研究发展规划项目(G1998040702)
国家自然科学基金(49774230)共同资助
中国地震局地球物理勘探中心论著 RCEG200133.
关键词
渤海湾
地震测深
地壳
上地幔
速度结构
地震界面
断裂带
deep seismic sounding
crust and upper mantle
velocity structure
seismic interfaces
