Strain-rate Field of Japan Estimated from GNSS Data and Its Interpretation Based on Inter- and Intra-arc Deformation
Strain-rate Field of Japan Estimated from GNSS Data and Its Interpretation Based on Inter- and Intra-arc Deformation
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DOI：
10.5026/jgeography.131.479
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发表时间：
2022-10
期刊：
影响因子：
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通讯作者：
Y. Fukahata;Tomohisa Okazaki;T. Nishimura
中科院分区：
文献类型：
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作者：
Y. Fukahata;Tomohisa Okazaki;T. Nishimura
― ―摘要如何利用空间离散的大地测量数据估计应变速率场是一个长期存在的问题。本文介绍了一种基于赤池贝叶斯信息量准则（ABIC）的基函数展开方法，该方法能客观、稳定地得到应变速率场。通过将该方法应用于日本的GNSS数据，获得了三个时期的应变速率场：1997 - 1999，2006 - 2009和2017 - 2020。除了与火山活动和大地震有关的变形外，所获得的应变速率场在时间上大致稳定，但在空间上表现出很大的变化。为了解释这种空间上的不均匀变形，使用了岛弧间和岛弧内变形的框架，考虑到日本群岛由五个岛弧（千岛群岛、日本东北部、日本西部、伊豆小笠原和琉球）组成，这些岛弧的定义几乎没有歧义，尽管在本研究中东北部和西部的日本岛弧被统称为本州岛弧。千岛岛弧与本州岛弧之间的岛弧间变形以东西向收缩为特征，伊豆小笠原岛弧和本州岛弧以南北向-北西向-东南向收缩为特征，琉球岛弧和本州岛弧以南北向伸展和东西向收缩为特征。关于弧内变形，千岛岛弧从太平洋海岸到火山弧后部显示出高应变率，伊豆小笠原岛弧的最北端显示出明显的东西向至东北向-西南向伸展，琉球岛弧显示出南北向伸展，伴随东西向收缩，类似于本州岛弧的弧间变形，尽管向南的东西向收缩较弱。本州岛弧显示出沿着日本海东缘，经过新泻-科比构造带（NKTZ）到中央构造线，以及沿着大坂主干山脉的高应变率带，而在中国区以及从茨木县北方，经过北方关东区到爱知县北方的带，该区域被命名为日立三川弧前低应变速率带（HMLSZ）。
― ― Abstract How to estimate a strainrate field from spatially discrete geodetic data has been a long standing issue. In this paper, a method based on basis function expansion with Akaike’s Bayes ian information criterion （ ABIC ） is introduced, by which strainrate fields can be obtained objec tively and stably. By applying the method to GNSS data in Japan, strainrate fields are obtained for three periods: 1997 1999, 2006 2009, and 2017 2020. Except for deformation related to volcanic activity and large earthquakes, the obtained strainrate fields are roughly stationary in time, while showing large variations in space. In order to interpret such spatially heterogeneous deformation, a framework of interarc and intraarc deformation is used, considering Japanese Islands to be composed of five island arcs （ Kuril, northeast Japan, west Japan, Izu Bonin, and Ryukyu ） and that these island arcs are defined with little ambiguity, though the northeast and westJapan arcs are collectively treated as the Honshu arc in this study. Interarc deformation between the Kuril and Honshu arcs is characterized by EW contraction, the Izu Bonin and Honshu arcs by NS to NW SE contraction, and the Ryukyu and Honshu arcs by NS extension with EW contraction. Regarding intraarc deformation, the Kuril arc shows high strain rates from the Pacific coast to the back of the volcanic arc, the northernmost part of the Izu Bonin arc shows significant EW to NE SW extension, and the Ryukyu arc shows NS extension with EW contraction similar to the interarc deformation with the Honshu arc, although the EW contrac tion is weaker to the south. The Honshu arc shows zones of high strain rates along the eastern margin of the Japan Sea via the Niigata Kobe tectonic zone （ NKTZ ） to the Median Tectonic Line and along the Oubackbone Range, while it also shows low strain rates in the Chugoku district and in the zone from northern Ibaraki prefecture via the northern Kanto district to northern Aichi prefecture, which is named the Hitachi Mikawa forearc low strainrate zone （ HMLSZ ） .