福州盆地及其周围地区地壳深部结构与构造的初步研究  

PRELIMINARY RESEARCH OF THE CRUSTAL STRUCTURE IN FUZHOU BASIN AND ITS ADJACENT AREA

作　　者：廖其林[1] 王振明[1] 邱陶兴[1] 袁定强[1] 王洪涛[1] 吴宁远[2] 刘宝诚[3] 

机构地区：[1]福建省地震局 [2]国家地震局 [3]北京大学地球物理系

出　　处：《地球物理学报》1990年第2期163-173,共11页Chinese Journal of Geophysics

基　　金：地震科学联合基金

摘　　要：1986—1988年,福建省地震局在福州盆地及其周围地区完成了五条地震测深剖面:宁德—永春剖面;洪懒—宁德剖面;莲峰—福州(尚干)剖面;南平—永泰—平潭非纵剖面;并在宁德—古田—嵩口首次试验扇形剖面观测系统,结果表明,扇形剖面对确定断裂是有效的. 根据对地震波走时的正、反演计算,用理论地震图和射线追踪方法进一步修改和完善,得到了福州盆地及其周围地区地壳深部为高、低速相间的速度分布特征.地壳介质速度为6.40km/s,在中地壳普遍发育一层速度为5.80—5.90 km/s、厚度约5.0 km的低速层.Moho面深度30—33 km,福州盆地为一Moho面隆起区,隆起幅度达3.0 km.北西向断裂发育,其中,闽江断裂在纵剖面和扇形剖面均有明显的反映,并切割到Moho面2.0—3.0 km. 反射波谱频方法计算得到福州盆地地壳Q值仅120—150,比邻近地区明显偏低,中地壳低速层Q值为40—80,是一典型的低速—高导—低Q(高衰减)结构层,此层上界面埋深14—15 km,与居里面埋深较一致.这些结果为福州地区的地热资源远景预测和开发提供了地壳深部结构和某些地球物理场背景.Five deep seismic sounding profiles, including Ningde-Yongchun, Hongnai-Ningde andLiangfeng-Fuzhou longitudinal profiles, Nanping-Yongtai-Pingtan non-longitudinal profile and Ningde-Gutian-Songkou fan profile, have been carried out by Fujian Seismological Bureau respectively in 1986 and 1988. The fan profile which has been tested for the first time in China is successful to determin the deep faults.Based on direct and inverse, synthetic seismograms and ray tracing calculations, the crust in Fuzhou basin and its adjacent area are found to consist of high and low velocity layers which-average to a velocity of 6.40km/s. In the middle crust, there is a low velocity layer of thickness about 5.0 km with 5.80-5.90 km/s velocity. The depth of Moho-surface is 30-33 km, but the layer arches upwards in Fuzhou basin with about 3.0 km amplitude. The faults in the northwest direction are well-developed, and one of which is Min River fault with 2.0-3.0 km amplitude on Moho-surface.Using reflection spectrum analysis method, the crustal Q value Fuzhou basin is found to-be only 120-150, lower than that in its adjacent area. The Q value in the low velocity layer is only 40-80, shows a typical low velocity - high conductivety - low Q structure. The buried depth of this layer's top-surface is consistent with that of the Curie-surface. These results provide the deep crustal structure and some geophysical fields background for assessing and developing the geothermal resources in the Fuzhou basin.

关 键 词：盆地 地壳 测深 结构 构造 地震 

分 类 号：P313[天文地球—固体地球物理学]