プレート運動と,グローバル・ダイナミック・モデルのストレス
Attreyee Ghosh1, William E Holt
1Geosciences Department, Stony Brook University, Stony Brook, NY 11794, USA. atreig@gmail.com
Science (New York, N.Y.)
|February 21, 2012
まとめ
この研究は,地球の浅い構造とマントルの流れを組み込み,プレート運動とストレスを正確に予測するグローバルダイナミックモデルを提示しています. この発見は,これらの要因が,地球規模で構造板の移動をどのように推進するか,または抵抗するか,明らかにしています.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- テクトニクス (地質学) とは
- コンピューティング・モデリング
背景:
- プレート運動の原動力の理解は,地球科学にとって極めて重要です.
- プレート運動,変形,およびストレスを予測することは,数値モデリングの課題です.
研究 の 目的:
- プレート運動と関連するパラメータを予測するためのグローバルダイナミックモデルを開発する.
- 浅い地球の構造とマントルの流れがプレート構造に及ぼす影響を調査する.
主な方法:
- 横の粘度変動 (上部200km) を含むグローバルダイナミックモデルを開発しました.
- トポグラフィー,リトスフィアの構造,マントルのフローカップリングからの力も含まれています.
- プレート運動とストレスの全般的な観測に対して検証されたモデル.
主要な成果:
- モデルはプレート運動,境界変形,剛性,およびストレスなどのパラメータに正確に適合します.
- 浅い構造とマントルの流れの相対的な重要性が地理的に異なることを実証しました.
- マントルの流れがプレート運動を駆動または抵抗する特定された領域.
- 図示されている沈殿板は,観測結果と一致するように強いストレスの誘導を必要としません.
結論:
- 横の粘度変動とマントルの流れ結合は,プレート構造を正確にモデル化するための鍵です.
- 浅い地球の構造と深いマントルのダイナミクスの相互作用がプレートの振る舞いを支配する.
- グローバルプレート運動とストレスは,沈下したスラブからの強いストレス誘導効果に頼らずに説明できます.
関連する概念動画
01:15Stress: General Loading Conditions
To grasp the intricacy of real-world conditions where multiple loads are applied simultaneously to a structure, one might visualize a section passing through a specific point within a body, aligned parallel to the xy plane. This section is subjected to various forces, including original loads, normal forces, and shearing forces.
The shearing force, possessing potential directionality within the plane of the section, is simplified into two component forces running parallel to the x and y axes.
The shearing force, possessing potential directionality within the plane of the section, is simplified into two component forces running parallel to the x and y axes.
01:24Principal Stresses
The graphical depiction of normal and shearing stress equations is represented by a circle, demonstrating the interplay between these stresses under different angular conditions. The center of this circle C, located on the vertical axis, represents the average normal stress, while its radius shows the range of stress variations. At points A and B, where the circle intersects the horizontal axis, the maximum and minimum normal stresses are observed, occurring without shearing stress. These...
01:18Transformation of Plane Stress
Studying stress transformation is essential in understanding how stress components within a material, like a cube under plane stress, change with rotation. This change is analyzed by considering a prismatic element within the cube. As the element rotates, the stress components acting on it—both normal and shearing stresses—change in magnitude and orientation. This change is quantified using trigonometric functions of the rotation angle, relating the forces acting on the rotated element's faces...
01:21General State of Stress
The general state of stress within a material can be accurately depicted using a stress tensor. This tensor encapsulates the internal forces distributed within a material subjected to external forces or deformations.
Specifically, consider a tetrahedral element where one face, labeled XYZ, is perpendicular to the line OA, and the remaining faces align with the coordinate axes with point O as the origin. At any point, such as point O, the stress tensor can be used to determine the stress...
Specifically, consider a tetrahedral element where one face, labeled XYZ, is perpendicular to the line OA, and the remaining faces align with the coordinate axes with point O as the origin. At any point, such as point O, the stress tensor can be used to determine the stress...
01:23Stresses under Combined Loadings
When analyzing a bent tube with a circular cross-section subjected to multiple forces, it is crucial to determine the stress distribution in order to maintain structural integrity under varied load conditions.
The process begins by slicing the tube at critical points and analyzing the internal forces and stress components at these sections, focusing on the centroid. Normal stresses, generated by axial forces and bending moments, are either compressive or tensile and vary across the section from...
The process begins by slicing the tube at critical points and analyzing the internal forces and stress components at these sections, focusing on the centroid. Normal stresses, generated by axial forces and bending moments, are either compressive or tensile and vary across the section from...
01:15Principal Stresses: Problem Solving
When analyzing two planes intersecting at right angles under the influence of shearing, tensile, and compressive stresses, it is essential to identify principal planes, maximum shearing stress, and principal stresses. To find the principal planes, apply a formula that equates them to twice the shearing stress divided by the difference between tensile and compressive stresses.