Analytic Studies of Seismic Waves in 3-D Structures

3-D 结构中地震波的分析研究

• 批准号: 8708564
• 负责人: Paul Richards
• 金额: $ 10万
• 依托单位: Columbia University Lamont Doherty Earth Observatory
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-07-15 至 1989-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8708564&HistoricalAwards=false
• 关键词: Analytic; Studies; Seismic; Waves; Structures

Wave propagation in layered media has been fruitfully studied for several decades, with many applications in geophysics and other fields. The fundamental limitation of this type of modelling, in most cases, is its inability to handle lateral variations of structure. A recent discovery now indicates that analytical methods, developed and widely used for layers with plane parallel interfaces, can be extended to the case of plane interfaces that are not parallel. Consequently, it appears possible to develop a generalized ray theory for wave propagation in a stack of wedge-shaped layers. Layer interfaces can have arbitrary dip and strike, permitting the study of waves in truly three-dimensional structures. The methods that can be so generalized, from parallel layering to non-parallel, are those that derive from a fundamental and well-known relationship between travel- time, range, and a sum over vertical slownesses (weighted by layer thickness). It is remarkable that this relationship, so familiar in purely depth-dependent structures, is virtually unchanged in the three- dimensional case. We propose to explore the newly generalized methods to study wave propagation associated with randomly dipping interfaces.

几十年来，人们对层状介质中的波传播进行了卓有成效的研究，并在地球物理等领域得到了广泛的应用。在大多数情况下，这种类型的建模的基本限制是它无法处理结构的横向变化。最近的一项发现表明，发展并广泛应用于具有平面平行界面的层的分析方法可以推广到非平行的平面界面的情况。因此，似乎有可能发展一种广义的射线理论来描述波在一堆楔形层中的传播。地层界面可以有任意的倾角和走向，从而可以研究真正三维结构中的波。可以如此概括的方法，从平行分层到非平行，是那些从旅行时间、射程和垂直慢度之和(按层厚度加权)之间的基本和众所周知的关系得出的方法。值得注意的是，这种在纯深度相关结构中非常常见的关系，在三维情况下几乎没有变化。我们建议探索新的广义方法来研究与随机倾斜界面相关的波的传播。