パンチボウル断層の断裂表面エネルギー,サンアンドレアス系
Judith S Chester1, Frederick M Chester, Andreas K Kronenberg
1Center for Tectonophysics, Department of Geology & Geophysics, Texas A&M University, College Station, Texas 77843-3115, USA. chesterj@geo.tamu.edu
Nature
|September 2, 2005
まとめ
地震の断裂エネルギーは,地震学的データによって著しく過小評価されています. パンチボウル断層の構造分析は,断層の表面の形成は,これまで考えられていたよりもはるかに多くのエネルギーを要求し,追加の滑り弱化のプロセスを示唆しています.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- 構造地質学 構造地質学
- 地震学 地震学とは
背景:
- 地震の断裂ダイナミクスの構成要素である断裂エネルギーは,その大きさと断裂表面形成と滑り弱化のメカニズムについてほとんど理解されていません.
- 地震学および実験データに基づく既存の推定は,地震破裂のエネルギー予算を完全に説明することはできません.
研究 の 目的:
- 大面積の掘り起こされた断層における断層表面の形成に必要なエネルギーを定量化するために.
- これらの定量化されたエネルギー需要を,地震の断裂エネルギーに関する地震学的推定値と比較する.
- 破裂表面の生成が地震中の全体的な滑り弱化に与える影響を調査する.
主な方法:
- サンアンドレアス断層システムの主要な発掘された断層であるパンチボウル断層の構造分析.
- 観測された断層構造に基づいて,断層表面積と関連するエネルギー需要の定量化.
主要な成果:
- パンチボウル断層の断裂表面面積を生成するのに必要なエネルギーは,地震学者が1つの大きな地震について推定するエネルギーの約300倍です.
- すべての断裂エネルギーを断裂表面の生成にのみ帰属すると,1km未満の地震の移動が観測された表面面積を説明できると示唆されます.
結論:
- 地震の断裂エネルギーに対する地震学的見積もりは,実際のエネルギー予算を大幅に過小評価している可能性があります.
- 断層表面の生成だけでは,大規模な地震における滑り弱化の際に散らばるエネルギーの総量を説明することはできません.
- 表面破裂を超えた追加の物理的プロセスは,地震破裂イベントの際に滑り落ちの弱まりに大きく寄与する可能性があります.
関連する概念動画
01:07Frictional Force
When a body is in motion, it encounters resistance because the body interacts with its surroundings. This resistance is known as friction, a common yet complex force whose behavior is still not completely understood. Friction opposes relative motion between systems in contact, but also allows us to move. Friction arises in part due to the roughness of surfaces in contact. For one object to move along a surface, it must rise to where the peaks of the surface can skip along the bottom of the...
01:27Fractures: Bone Repair
Treatment for a fracture is based on the type of break, the bone affected, and the patient's age.
Minor fractures with no bone displacement are treated by immobilizing the fractured bone using a cast or splint. However, in the case of fractures with displaced bones, the broken bones are repositioned before immobilization to ensure successful healing without deformation and loss of function. The realignment of fractured bone ends is performed through a process called reduction. If the procedure...
Minor fractures with no bone displacement are treated by immobilizing the fractured bone using a cast or splint. However, in the case of fractures with displaced bones, the broken bones are repositioned before immobilization to ensure successful healing without deformation and loss of function. The realignment of fractured bone ends is performed through a process called reduction. If the procedure...
01:16Surface Tension and Surface Energy
When a paint brush is immersed in water, the bristles wave freely inside the water. When it is taken out, the bristles stick together. The reason behind this effect is surface tension.
Consider a beaker filled with liquid. The bulk molecules in the liquid experience equal attractive forces on all sides with the surrounding molecules. However, the surface molecules experience a net attractive force downward due to the bulk molecules. The surface of the liquid behaves like a stretched membrane,...
Consider a beaker filled with liquid. The bulk molecules in the liquid experience equal attractive forces on all sides with the surrounding molecules. However, the surface molecules experience a net attractive force downward due to the bulk molecules. The surface of the liquid behaves like a stretched membrane,...
01:24Stress-Strain Diagram - Brittle Materials
Brittle materials, including glass, cast iron, and stone, exhibit unique characteristics. They fracture without considerable change in their elongation rate, indicating that their breaking and ultimate strength are equivalent. Such materials also show lower strain levels at the point of rupture. The failure in brittle materials predominantly results from normal stresses, as evidenced by the rupture created along a surface perpendicular to the applied load. These materials do not display...
01:16Flexural Stress
When analyzing bending in symmetric members, it's crucial to understand how stresses distribute when subjected to bending moments. This stress distribution is effectively described by applying fundamental mechanics and material science principles, particularly Hooke's Law for elastic materials.
Hooke's Law states that within the material's elastic limits, stress is directly proportional to strain. In a member experiencing a bending moment, the strain at any point is relative to its distance...
Hooke's Law states that within the material's elastic limits, stress is directly proportional to strain. In a member experiencing a bending moment, the strain at any point is relative to its distance...
01:24Surface Tension
Surface tension is defined as the force per unit length (γ) acting along the surface of a liquid. It arises due to strong intermolecular forces of attraction. A molecule located inside the bulk of the liquid is surrounded by other molecules and experiences equal forces in all directions. However, a molecule at the surface experiences unbalanced forces because there are more neighboring molecules below than above. This creates a net inward force that pulls surface molecules toward the interior,...