Seismic anisotropy in the big mantle wedge and mantle transition zone of the northwestern Pacific subduction system
文献类型：期刊论文
| 作者 | Guo GuangRui1,4; Li Juan1,3,4; Chen SiDan1,4; Mooney, Walter D.2 |
| 刊名 | CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION
 |
| 出版日期 | 2021-02-01 |
| 卷号 | 64期号:2页码:455-470 |
| 关键词 | Anisotropy Shear wave splitting Big mantle wedge Mantle transition zone Frequency dependence Two-layer anisotropy model Simultaneous multi-waveform inversion (SIMW) |
| ISSN号 | 0001-5733 |
| DOI | 10.6038/cjg2020O0233 |
| 英文摘要 | The morphologies of subducting slabs have been clearly imaged by seismic tomographic techniques, however, the character of the mantle flow associated with subduction process remains ambiguous. Both trench parallel and trench normal patterns of seismic anisotropy have been reported in various mantle-wedge subduction systems. Here we investigate the anisotropic characteristics in the "Big Mantle Wedge" that is formed by the stagnation of the subducting Pacific slab. A detailed shear wave splitting study was conducted on the SKS phase and the direct S-wave phase of regional deep-source earthquakes of MDJ station, which has a long-term stable observation data. Simultaneous multi-waveform inversion (SIMW) method is used to obtain more accurate SKS phase anisotropy results on the basis of guaranteeing the azimuth coverage. We identified prominent frequency dependence and initial polarization variability in apparent splitting parameters, indicating the presence of multiple possible sources of anisotropy. Two-layer anisotropic model fitting based on the SIMW results in different frequency bands shows a trench-oblique fast direction of phi=32 degrees +/- 12 degrees, delta t=1.4 +/- 0.4 s in the upper layer, attributed to the fossil anisotropy in the lithosphere affected by the Tan-Lu fault zone. And a nearly trench-normal fast direction of phi= - 71 degrees +/- 6 degrees, delta t=2.4 +/- 0.4 s in the lower layer. The large delay time in the lower layer indicates the presence of anisotropy within the mantle transition zone and possibly deeper. The trench-normal fast axis direction may be due to the combined effects of the lattice preferred orientation (LPO) of olivine caused by asthenosphere flow in the shallow mantle, and the LPO of wadsleyite caused by the lateral mantle flow associated with the stagnation of the Pacific slab. |
| WOS关键词 | WAVE SPLITTING OBSERVATIONS ; NORTHEAST CHINA ; EASTERN CHINA ; SHEAR-VELOCITY ; BENEATH ; DEFORMATION ; SKS ; DISCONTINUITIES ; WELLINGTON ; PRESSURE |
| WOS研究方向 | Geochemistry & Geophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:000617909800006 |
| 出版者 | SCIENCE PRESS |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/100121]  |
| 专题 | 地质与地球物理研究所_中国科学院地球与行星物理重点实验室 |
| 通讯作者 | Li Juan |
| 作者单位 | 1.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China 2.US Geol Survey, Menlo Pk, CA 94025 USA 3.Chinese Acad Sci, Inst Geol & Geophys, Mohe Natl Observ Geophys, Beijing 100029, Peoples R China 4.Univ Chinese Acad Sci, Beijing 100049, Peoples R China |
| 推荐引用方式 GB/T 7714 | Guo GuangRui,Li Juan,Chen SiDan,et al. Seismic anisotropy in the big mantle wedge and mantle transition zone of the northwestern Pacific subduction system[J]. CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,2021,64(2):455-470. |
| APA | Guo GuangRui,Li Juan,Chen SiDan,&Mooney, Walter D..(2021).Seismic anisotropy in the big mantle wedge and mantle transition zone of the northwestern Pacific subduction system.CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,64(2),455-470. |
| MLA | Guo GuangRui,et al."Seismic anisotropy in the big mantle wedge and mantle transition zone of the northwestern Pacific subduction system".CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION 64.2(2021):455-470. |
入库方式： OAI收割
来源：地质与地球物理研究所
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