上层板块的刚性决定了巨型地震的深度变化
Valentí Sallarès1, César R Ranero2,3
1Barcelona Center for Subsurface Imaging, Institute of Marine Sciences, CSIC, Barcelona, Spain. vsallares@icm.csic.es.
Nature
|November 29, 2019
概括
与更深层地震相比, 浅层巨型地震表现出不同的破裂行为. 这项研究表明岩石刚性的变化, 而不是故障机制, 解释了这些差异, 可能有助于海预警.
科学领域:
- 地质学
- 地震学
- 地震科学
背景情况:
- 在潜伏区的巨大地震显示了深度依赖的破裂特征.
- 浅层破裂比深层破裂有更大的滑动,更长的持续时间和不同的能量辐射.
- 这些特性导致破坏性海的发生,
研究的目的:
- 确定观察到的依赖于深度的地震破裂行为的基本物理原因.
- 开发一个量化框架,将地震源属性与焦点深度联系起来.
- 改善地震滑坡,地震强度和海的预测.
主要方法:
- 分析全球潜伏区的压缩波速度模型.
- 将现实的弹性特性与精确的地震焦点深度估计相结合.
- 在主导上板中的动态应力转移的建模.
主要成果:
- 上面板的硬度有系统的变化被认为是常见的原因.
- 这种刚性变化解释了对比的破裂行为,而不会引起故障机制的变化.
- 该模型成功地预测了共地震滑动和地震强度.
结论:
- 主要板块的硬度变化取决于深度,这决定了巨型地震的破裂行为.
- 这一发现为观测到的地震现象提供了统一的物理解释.
- 这些结果有助于改进地震强度估计和海预警系统.
相关概念视频
Stress-Strain Diagram - Brittle Materials
3.6K
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...
3.6K
Relation between Poisson's ratio, Modulus of Elasticity and Modulus of Rigidity
498
Deformation occurs in axial and transverse directions when an axial load is applied to a slender bar. This deformation impacts the cubic element within the bar, transforming it into either a rectangular parallelepiped or a rhombus, contingent on its orientation. This transformation process induces shearing strain. Axial loading elicits both shearing and normal strains. Applying an axial load instigates equal normal and shearing stresses on elements oriented at a 45° angle to the load axis.
498
Plastic Behavior
479
A material's elastic behavior is characterized by the disappearance of stress once the load is removed, allowing the material to return to its original state. However, when stress surpasses the yield point, yielding commences, marking the onset of plastic deformation or permanent set. This change from elastic to plastic behavior is influenced by the peak stress value and the duration before the load is removed. An intriguing observation occurs when a specimen is loaded, unloaded, and...
479
Plastic Deformations
365
It is essential to understand how structural members behave under plastic deformation when the bending stress exceeds the material's yield strength. This state of deformation permanently alters the shape of the member, in contrast to the linear elastic behavior observed before yielding. The strain at any point in the member is expressed in terms of maximum strain. Notably, the neutral axis, which coincides with the centroid during elastic bending, shifts away from the centroid under plastic...
365
Plastic Deformations
373
Plastic deformation represents a fundamental concept in materials science, which explains the irreversible change in the shape of a material when it experiences stress beyond its elastic capability. This phenomenon is important in structural engineering, especially in designing and analyzing cantilever beams—structures that are securely fixed at one end and bear loads at the opposite end. When these beams are subjected to loads within their elastic range, they will return to their...
373
Plastic Deformation in Circular Shafts
409
When materials are subjected to forces that surpass their yield strength, they undergo a process known as plastic deformation. This results in a permanent alteration or strain in their structure. This concept can be specifically applied to circular shafts, where the deformation leads to a change in its shape. The precise evaluation of this plastic deformation requires understanding the stress distribution within the circular shaft, which is achieved by calculating the maximum shearing stress in...
409


