日本地球惑星科学連合2023年大会

講演情報

[J] オンラインポスター発表

セッション記号 M (領域外・複数領域) » M-IS ジョイント

[M-IS12] 地球流体力学:地球惑星現象への分野横断的アプローチ

2023年5月24日(水) 09:00 〜 10:30 オンラインポスターZoom会場 (4) (オンラインポスター)

コンビーナ:伊賀 啓太(東京大学大気海洋研究所)、吉田 茂生(九州大学大学院理学研究院地球惑星科学部門)、柳澤 孝寿(国立研究開発法人海洋研究開発機構 海域地震火山部門)、相木 秀則(名古屋大学)

現地ポスター発表開催日時 (2023/5/23 17:15-18:45)

09:00 〜 10:30

[MIS12-P01] 2-D cylindrical mantle convection simulations on tectonic plates with stress-history-dependent rheology model

*田井東 大貴1亀山 真典2 (1.愛媛大学大学院理工学研究科 、2.愛媛大学地球深部ダイナミクス研究センター)


キーワード:応力履歴依存レオロジー、マントル対流、プレートテクトニクス

Reproducing plate tectonics is one of the most important goals of numerical simulations on mantle convection. In this study, we developed a numerical model of thermal convection of the Earth’s mantle in a 2-D cylindrical geometry making use of the stress-history-dependent rheology (Ogawa, 2003; Miyagoshi et al., 2020), which enables us to distinguish the stiff, mechanically strong plate interior and soft, highly deformable boundaries on the lithosphere. In a series of preliminary calculations we obtained the cases where the nature of highly viscous lithosphere of cold fluid is quite similar to that of the Earth’s plates; the lithosphere is divided into three or four pieces of surface plates each of which rigidly moves, and the surface heat flow of plates begins decreasing at divergent-plate-margin (ridge) in accordance with the half-space cooling model. By a careful comparison of our results with the earlier ones using 2-D Cartesian geometry (Ogawa, 2003), we also found that the cold lithosphere becomes thicker owing to an enhanced cooling by the effect of spherical geometry, which in turn affects the stress levels generated in the lithosphere. This may further imply that the condition for reproducing plate- like behavior in the 2-D or 3-D spherical mantle is slightly different from that estimated earlier by the Cartesian models.