フィリピン海プレート北端部の沈み込み・衝突の3次元FEMモデル

• 河内 崇

  茨城大学大学院理工学研究科

• 宮下 芳

  茨城大学大学院理工学研究科

書誌事項

タイトル別名

• 3-Dimensional Finite Element Modeling of the Subduction and Collision of the Northernmost Part of the Philippine Sea Plate
• フィリピンカイ プレート ホクタンブ ノ シズミコミ ショウトツ ノ 3ジゲン

抄録

The northernmost part of the Philippine Sea plate is thought to be subducting beneath the continental plate from the Sagami and Suruga troughs, and to be colliding with the continental plate in the northern end of the Izu peninsula. Four major interplate earthquakes (i. e., the 1703 Genroku, 1707 Hoei, 1854 Ansei-Tokai and 1923 Kanto earthquakes) have occurred along the Sagami and Suruga troughs since the beginning of the 18th century. The stress field observed in and around this subduction and collision zone indicates several features; radial pattern of the maximum principal stress axes and concentric pattern of the minimum principal stress axes. The model of the seismotectonics for the last two centuries is investigated on the basis of numerical simulations of the stress field by applying a 3-dimensional finite element method.<BR>The tectonic stress accumulation and release processes are incorporated by assuming that (1) the Philippine Sea plate is moving steadily against the continental plate at a velocity of 4 cm/yr in a direction of N30°W, and (2) the earthquake and the steady-state faulting occur across the sub-surfaces of the plate boundary surface between the Philippine Sea and continental plates. The distribution of elastic shear coupling strengths on the sub-surfaces, which determines the amount of faulting, is estimated as follows: the sub-surfaces along the Sagami and Suruga troughs are relatively weakly coupled, compared with the northwestern part of the plate boundary surface. The present seismotectonic model can approximately explain the features of the observed stress field. It can be explained that the characteristic distribution of horizontal tension axes is caused by the bending of the Philippine Sea plate associated with the subduction along the Sagami and Suruga troughs.

収録刊行物

• 地震　第２輯

  地震　第２輯 50 (2), 229-240, 1997

  公益社団法人 日本地震学会

キーワード

• 3-Dimensional finite element method
• 3-Dimensional inhomogeneous structure
• Subduction and collision of the Philippine Sea plate
• Bending of the Philippine Sea plate
• Elastic shear stress strength

詳細情報

• CRID: 1390001204307246336
• NII論文ID: 10002501357
• NII書誌ID: AN00305741
• DOI: 10.4294/zisin1948.50.2_229
• ISSN: 18839029
• ISSN: 2186599X
• ISSN: 00371114
• NDL書誌ID: 4292600
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I4292600
• Web Site: https://www.jstage.jst.go.jp/article/zisin1948/50/2/50_2_229/_pdf
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