Depth of the Moho discontinuity beneath the Japanese islands estimated by traveltime analysis
Depth of the Moho discontinuity beneath the Japanese islands estimated by traveltime analysis
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DOI：
10.1029/2008jb005864
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发表时间：
2010-04-02
影响因子：
3.9
通讯作者：
Katsumata, Akio
中科院分区：
文献类型：
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作者：
Katsumata, Akio
利用区域体波到达时间的层析反演法估计了日本岛屿下方的地壳结构，包括康拉德面和莫霍面的深度分布。表层底部、康拉德和莫霍面的深度分布用二维B样条函数模拟，而层内的速度分布用三维B样条函数表示。用最小二乘法同时估计了不连续面的深度和层间速度。速度结构从浅层到深层依次估计，避免了它们之间的相关性。这种顺序分析提供了更高的深度分辨率。莫霍面最深处位于本州中部，长约40公里。莫霍面一般在岛屿的中部较深，而在本州的关东、中部、中部和中部地区以及九州北部相对较浅。中新世以来，一些浅层莫霍面地区可能与伸展构造应力作用下的地台建造有关。与地震折射测量和接收函数分析的结果进行了比较，发现所得到的模型与这些研究中的许多结果是一致的。
The crustal structure beneath the Japanese islands, including depth distributions of the Conrad and Moho discontinuities, was estimated using a tomographic inversion of regional body wave arrival times. Depth distributions of the bottom of the surface layer, the Conrad, and the Moho were modeled with two-dimensional B spline functions, while velocity distributions in layers were expressed by three-dimensional B spline functions. The depth of the discontinuities and the velocity in the layers were estimated simultaneously by the least squares method. The velocity structure was sequentially estimated from shallower parts to deeper parts to avoid correlation between them. This sequential analysis provided improved depth resolution. The deepest region of the Moho discontinuity was located in central Honshu, reaching about 40 km. The Moho discontinuity was generally deep in the central part of the islands, whereas it was relatively shallow in the Kanto, southwestern Chubu, and Chugoku districts in Honshu and in northern Kyushu. Some of the shallow Moho regions would be related to graben formation due to tensile tectonic stress since the Miocene. The results were compared with those of seismic refraction surveys and receiver function analyses, and it was found that the obtained model was consistent with many of these studies.