Subduction of the Philippine Sea plate beneath southwestern Japan: Slab geometry and its relationship to arc magmatism
Subduction of the Philippine Sea plate beneath southwestern Japan: Slab geometry and its relationship to arc magmatism
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DOI：
10.1029/2006jb004770
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发表时间：
2007-08-11
影响因子：
3.9
通讯作者：
Hasegawa, Akira
中科院分区：
文献类型：
--
作者：
Nakajima, Junichi;Hasegawa, Akira
我们进行了高分辨率的三维地震层析成像的地壳和上地幔下西南（SW）日本使用到达时间从全国地震台网获得的数据。层析图像提供了新的见解菲律宾海板块和弧岩浆的配置。结果证实了存在的一个aseperentum部分的菲律宾海板块在更大的深度超出地震部分。菲律宾海板块正在地震俯冲，在中部至少有200 km的深度，在近畿60-80 km，在中国60 km，在九州地震俯冲到150-200 km的深度。在中部地区，它以浅倾角地震俯冲，然后向下弯曲到火山区下方，而在近畿地区，它以近水平的方式俯冲到日本海。相邻地区之间的板片几何形状的差异与火山活动的差异相关，这表明菲律宾海板片的几何形状对弧岩浆活动的重要性。我们的断层图像进一步暗示菲律宾海板块俯冲到伊豆半岛西北约70公里的深度。该区域的菲律宾海板块可能被板块撕裂分开为西部和东部，并在150-200公里深处与太平洋板块碰撞。
We carry out high-resolution three-dimensional seismic tomography of the crust and upper mantle beneath southwestern (SW) Japan using arrival-time data obtained from the nationwide seismograph network. The tomographic images provide new insights into the configuration of the Philippine Sea slab and arc magmatism. The results confirm the existence of an aseismic portion of the Philippine Sea slab at greater depths beyond the seismic portion. The Philippine Sea slab is subducting aseismically down to at least a depth of 200 km in Chubu, 60-80 km in Kinki, and 60 km in Chugoku and is subducting seismically to depths of 150-200 km in Kyushu. In the Chubu district, it is subducting seismically at a shallow dip and then bends downward beneath the volcanic area, whereas in the Kinki district, it is subducting subhorizontally as far as the Japan Sea. The differences in the slab geometry between adjacent regions correlate with the differences in volcanic activity, suggesting the importance of the geometry of the Philippine Sea slab on arc magmatism. Our tomographic images further imply subduction of the Philippine Sea slab down to a depth of around 70 km northwest of the Izu Peninsula. The Philippine Sea slab in that region might have split into western and eastern parts separated by a slab tear and collided with the Pacific slab at depths of 150-200 km.