Three-Dimensional Depth Structure of the Crust and Uppermost Mantle beneath Southwestern Japan and Its Regional Gravity Anomalies
Three-Dimensional Depth Structure of the Crust and Uppermost Mantle beneath Southwestern Japan and Its Regional Gravity Anomalies
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日本西南部地壳和上地幔的三维深度结构及其区域重力异常
DOI：
10.4294/zisin1948.52.1_51
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Kunihiro Ryoki
中科院分区：
文献类型：
--
作者：
Kunihiro Ryoki
在假定三维密度结构的情况下，计算了日本西南部的区域重力异常。重力效应的计算采用了以三棱柱体集合体为代表的结构模型，该模型是通过汇编该地区现有的大量地壳下表面和板块上表面深度资料而产生的。参考前人的研究成果，对太平洋板块、菲律宾海板块、上地壳、下地壳和软流层的密度进行了推测。计算结果表明，地壳的重力效应比板块的重力效应大，而板块的假定密度变化比地壳的重力效应更有效。用该方法进行的区域重力校正与空间滤波法和最小二乘法进行的区域重力校正的比较表明，前者比后者得到的局部重力异常更精确。利用上述方法可以计算出日本西南部任意一点的区域重力异常，进而进行更精确的区域重力校正，用于分析局部重力结构。
The regional gravity anomalies were calculated in Southwestern Japan presuming a threedimensional density structure. The gravitational effect was calculated by the structural model represented by aggregate bodies of triangular vertical prisms which was generated by compiling the existing vast amount of data on the depths of lower surface of the crust and upper surface of the plate slab in this region. The densities of the Pacific and Philippine Sea plate slabs, upper and lower crusts and asthenosphere were presumed referring to past research. It was shown by the calculation that the gravitational effect of the crust has larger amplitude than that of the plate slabs in this region, while variation of the presumptive density of the plate slab is more effective than that of the crust. Comparison of the regional gravity correction by means of the above method with the ones by the spatial filtering method and the least square method shows that the former derives more accurate local gravity anomaly than the latter. The regional gravity anomaly can be calculated by the above method at an arbitrary point in Southwestern Japan, and then more accurate regional gravity correction can be performed for the analysis of local gravity structure.