2020 Fiscal Year Final Research Report
Reason for Soft Asthenosphere Revealed by Seismic Waves
| Project/Area Number |
18K03798
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 17040:Solid earth sciences-related
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| Research Institution | The University of Tokyo |
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Principal Investigator |
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Keywords | リソスフェア / アセノスフェア / 地球内部構造 / プレートテクトニクス / トモグラフィー |
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| Outline of Final Research Achievements |
The purpose of this research project is inverting for the structures of oceanic lithosphere and asthenosphere to obtain answers for the fundamental questions, “Why is the lithosphere rigid?” and “Why is the asthenosphere soft?”. We compiled higher frequency waveforms recorded by OBSs and found that the attenuation of younger lithosphere is very strong. We also conducted inversion for P velocity structures, which were hardly constrained so far, to reveal the Vp/Vs structures. We found that the lithosphere is not chemically homogeneous and has chemical stratification. We also found that the effects of anelasticity or melt in the vicinity of the lithosphere-asthenosphere boundary.
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| Free Research Field |
固体地球物理学
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| Academic Significance and Societal Importance of the Research Achievements |
プレートテクトニクスは地球表層近傍の運動や活動を記述する基本的なモデルであり，そのしくみを制約することは地球科学の最大の課題の一つである．本計画は直接的な観測に基づき，この課題に挑んだものである．インパクトは認められ，発表した論文は編集者が選出したハイライト研究として，米国地球物理学連合(American Geophysical Union)のニュースレーターで紹介された．(https://eos.org/editor-highlights/unexpected-oceanic-lithosphere-asthenosphere-p-wave-velocities)
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