Development of a mathematical and computational model for long-term plate subduction

2023 Fiscal Year Final Research Report

• Project/Area Number: 18K18797
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 17:Earth and planetary science and related fields
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: Hori Takane 国立研究開発法人海洋研究開発機構, 海域地震火山部門(地震津波予測研究開発センター), センター長 (00359176)
• Project Period (FY): 2018-06-29 – 2024-03-31
• Keywords: 沈み込み / 準拠楕円体 / 粘弾性

Outline of Final Research Achievements

The purpose of this research is to construct a method that can appropriately calculate plate subduction phenomena on a geological time scale, and to incorporate the results into initial and boundary conditions for calculations on a geophysical time scale. We propose a basic idea when constructing a digital twin for the solid Earth is to calculate crustal deformation using the reference ellipsoid itself used in GNSS data analysis. Based on this idea, we calculate slip response functions for southwest Japan and northeast Japan, and a viscoelastic structure was introduced. Regarding stress evaluation along the fault plane, modeling of the fault plane and handling of the edges of the model space were found to be future issues in calculating long-term subduction.

Free Research Field

地震学

Academic Significance and Societal Importance of the Research Achievements

学術的な意義として、GNSSデータ解析で用いられる準拠楕円体そのものをモデル化して地殻変動などを計算することを提案したことは、固体地球を対象としたデジタルツインを構築する際に、観測データと計算モデルに共通のフレームワークを用いるという意味で、基礎となる考え方として重要である。また、長期的な沈み込みのモデル化において、プレート境界断層でのすべり面における応力評価の困難さが改めて浮き彫りになった。