来自地震异性质的潜水区流场:全球视图
Maureen D Long1, Paul G Silver
1Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015, USA. long@dtm.ciw.edu
概括
在俯冲过程中地幔流量通过分析地震异构性来更好地理解. 沟迁移速度影响地幔底下和地幔内的地幔流动模式,与趋同驱动的流动相互作用.
科学领域:
- 地质物理学 地质物理学
- 地震学 地震学
- 构造学 构造学 构造学 构造学
背景情况:
- 引板形态已被很好地理解,但相关的地幔流动仍然不清楚.
- 通过剪切波分裂观察到的地震异质性,为地幔流动提供了洞察力.
研究的目的:
- 为了描述与浮沉相关的地幔流动模式.
- 为了研究沟迁移和地幔流动之间的关系.
主要方法:
- 编制了来自13个俯冲区的剪切波分裂观测结果.
- 分析了与沟迁移速度 (gVt) 相对的地震异性变化.
主要成果:
- 观测到地幔和子岩异性与沟迁移速度的系统变化.
- 鉴定了沟平行流,由沟运动驱动,作为板块下面的主导.
- 表明这个沟-平行流量大小的尺度是V{\displaystyle V{\displaystyle T} .
- 在地幔中展示了沟平行流和收驱动的角流之间的相互作用.
结论:
- 沟迁移速度是控制潜水过程中地幔流动的关键因素.
- 沟-平行和角流的相对影响取决于二维V (t) 的大小和合速度V (c).
- 地震异质性有效地揭示了复杂的地幔流动动力学.
相关概念视频
Uniform Depth Channel Flow
Uniform depth channel flow keeps fluid depth consistent along channels such as irrigation canals. In natural channels, such as rivers, approximate uniform flow is often assumed. This condition occurs when the channel’s bottom slope matches the energy slope, balancing potential energy lost from gravity with head loss due to shear stress. This balance prevents depth changes along the channel length, resulting in a steady, uniform flow.Uniform flow in open channels with a constant cross-section...
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...
Irrotational Flow
Irrotational flow is characterized by fluid motion where particles do not rotate around their axes, resulting in zero vorticity. For a flow to be irrotational, the curl of the velocity field must be zero. This imposes specific conditions on velocity gradients. For instance, to maintain zero rotation about the z-axis, the gradient condition:
General External Flow Characteristics
The study of external flow is essential for creating structures and objects that interact efficiently and safely with moving fluids, such as air or water. When a body is immersed in a flowing fluid, it experiences two primary forces: drag, which opposes motion along the flow direction, and lift, which acts perpendicular to the flow. The shape, size, and orientation of the object influence these forces.Streamlined and Blunt Bodies in External FlowObjects in fluid flow are classified as...
Plane Potential Flows
Plane potential flows simplify fluid motion by assuming the fluid to be irrotational and incompressible. These characteristics allow these flows to be described by a velocity potential function, ϕ, representing the flow speed in a given direction, and a stream function, ψ, that visualizes the flow path, both governed by Laplace's equation. These parameters help in estimating flow patterns, velocity distributions, and pressure fields around various hydraulic structures.
Uniform Flow
Uniform flow...
Uniform Flow
Uniform flow...
Couette Flow
Couette flow represents the flow of fluid between two parallel plates, with one plate fixed and the other moving with a constant velocity. This configuration allows for a simplified analysis using the Navier-Stokes equations, which govern fluid motion under conditions of viscosity and incompressibility. For Couette flow, the assumptions include a steady, laminar, incompressible flow with a zero-pressure gradient in the flow direction. This flow type is beneficial for understanding shear-driven...


