サーペンタインの脱水による潜水地域地震性のシミュレーション
David P Dobson1, Philip G Meredith, Stephen A Boon
1Bayerisches Geoinstitut, Universität Bayreuth, D-95440 Bayreuth, Germany. d.dobson@ucl.ac.uk
まとめ
アンチゴライト・サーペンチナイトの脱水反応は地震信号を生成する. これらの発見は,脱水による流体圧が,構造板の沈下中間の深さで地震を引き起こす可能性があることを示唆しています.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- ミネラル物理学 ミネラル物理学
- 地震学 地震学とは
背景:
- アンチゴライト・サーペンチナイトは,地質プレート沈殿の重要な構成要素である.
- サーペンチナイト内の高圧・高温での脱水反応はほとんど解明されていません.
- 中間の深さ (50~200km) での地震性の生成は,地球科学における重要な問題であり続けています.
研究 の 目的:
- 実験室条件下で抗ゴライト脱水による地震的影響を調査する.
- 脱水反応を脆性変形と流体圧力生成と関連付けるため.
- サブドクションゾーンにおける中程度の深さの地震性のためのメカニズムを提供すること.
主な方法:
- 実験は,サブドクションゾーンの条件をシミュレートするために,マルチアンビルプレスを使用して実施されました.
- アンチゴライトの脱水過程で,1.5〜8.5 GPaの圧力範囲と300〜900 °Cの温度範囲で,音響放射エネルギーを測定した.
- 回収したサンプルは,微細構造と変形特性を分析した.
主要な成果:
- アンチゴライトの脱水過程で,音響放出信号が強く検出されました.
- 実験用サンプルを分析した結果,脆い変形構造が明らかになった.
- これらの構造は,脱水中に流体が放出されていることを示唆する,ポア流体圧力の上昇と関連していました.
結論:
- シミュレートされた潜水条件下でのアンチゴライト脱水は,重要な音響信号を生成します.
- 関連する脆い変形と高孔流体の圧力は,地震発生の妥当なメカニズムを提供します.
- サブダクションスラブにおける脱水反応は,中程度の深さの地震性の有効な源である.
さらに関連する動画
06:55Kinematic History of a Salient-recess Junction Explored through a Combined Approach of Field Data and Analog Sandbox Modeling
Published on: August 5, 2016
07:58Data Processing Methods for 3D Seismic Imaging of Subsurface Volcanoes: Applications to the Tarim Flood Basalt
Published on: August 7, 2017
関連する概念動画
Magnetostatic Boundary Conditions
An electric field suffers a discontinuity at a surface charge. Similarly, a magnetic field is discontinuous at a surface current. The perpendicular component of a magnetic field is continuous across the interface of two magnetic mediums. In contrast, its parallel component, perpendicular to the current, is discontinuous by the amount equal to the product of the vacuum permeability and the surface current. Like the scalar potential in electrostatics, the vector potential is also continuous...
Magnetic Susceptibility and Permeability
In linear magnetic materials, like paramagnets and diamagnets, magnetization is proportional to the magnetic field intensity. The constant of proportionality, a dimensionless number, is called magnetic susceptibility. The value of the susceptibility depends on the type of material.
When diamagnetic materials are placed under an external magnetic field, the moments opposite to the field are induced. Hence, the susceptibility for diamagnets has a minimal negative value of 10-5–10-6. Since...
When diamagnetic materials are placed under an external magnetic field, the moments opposite to the field are induced. Hence, the susceptibility for diamagnets has a minimal negative value of 10-5–10-6. Since...
Temperature Dependent Deformation
In a nonhomogeneous rod made up of steel and brass, restrained at both ends and subjected to a temperature change, several steps are involved in calculating the stress and compressive load. Due to the problem's static indeterminacy, one end support is disconnected, allowing the rod to experience the temperature change freely. Next, an unknown force is applied at the free end, triggering deformations in the rod's steel and brass portions. These deformations are then calculated and added together...
Elastic Strain Energy for Normal Stresses
Strain energy quantifies the energy stored within a material due to deformation under loading conditions, a fundamental concept in materials science and engineering. The strain energy can be modeled when a material is subjected to axial loading with uniformly distributed stress. In this scenario, the stress experienced by the material is the internal force divided by the cross-sectional area, and the strain induced is directly proportional to this stress through the modulus of elasticity.
If...
If...
Elastic Strain Energy for Shearing Stresses
As discussed in previous lessons, strain energy in a material is the energy stored when it is elastically deformed, a concept crucial in materials science and mechanical engineering. This energy results from the internal work done against the cohesive forces within the material. When a material undergoes shearing stress and corresponding shearing strain, the strain energy density, which is the energy stored per unit volume, is calculated. Within the elastic limit, where the stress is...
