Collaborative Research: CMG Research: Statistical Seismic Imaging

合作研究：CMG 研究：统计地震成像

• 批准号: 0222181
• 负责人: Susan Minkoff
• 金额: $ 19.27万
• 依托单位: University of Maryland Baltimore County
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-01 至 2006-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0222181&HistoricalAwards=false
• 关键词: Collaborative; Research; CMG; Statistical; Seismic

Collaborative Research: CMG Research: Statistical Seismic ImagingA. Levander, W.W. Symes, S. MinkoffBoth the crystalline crust and the shallow near surface ( 100m depth) environment are complex, mechanically heterogeneous regions, often having spatial distributions of mechanical properties that are distinctly different from the relatively smoothly layered sedimentary column. Exploration seismology is currently one of the most important means of exploring the subsurface: for petroleum in the sedimentary column, for geotechnical/environmental purposes in the shallow subsurface, and for understanding of tectonic processes in the crystalline crust. Reflection seismology was developed by the petroleum industry to explore the sedimentary column, i.e., the medium is layered, the preponderance of energy is singly scattered, and scales are dichotomous. Its applications in both the near-surface environment and the deep crust have been very successful but also present problems not usually encountered in petroleum exploration. The near surface is subjected to chemical and mechanical weathering processes that produce a highly heterogeneous, nonlayered medium. Mechanical properties can vary by an order of magnitude within a few wavelengths due to compaction, chemical alteration, and the presence or absence of water. The crystalline crust, although lacking order of magnitude changes in mechanical properties, has a spatially complex, often self-affine (fractal) distribution of seismic velocity and density heterogeneities. For the relatively long path propagation in the crust, the wavefield often falls in a strong scattering regime in which linear imaging systems will produce mediocre or nonsensical results.This research program makes first steps toward a complementary imaging paradigm for complex media, termed statistical seismic imaging, in which statistical properties of the subsurface are mapped using statistical properties of the seismic wavefield. As this is an extremely large topic, the proposal scope will be limited to a few areas of endeavor. The investigations will explore (1) effective models relating subwavelength scale heterogeneity to macro-scale propagation effects (effective mechanical properties, velocity, attenuation, dispersion, etc), (2) the extent to which multiple reflection and refraction can be differentiated and their effects on traditional seismic imaging, and (3) the identification of the onset of strong scattering. The research involves a high level of software development and computational effort, including 3D seismic simulation and nonlinear inversion for material properties and statistics. No single discipline possesses the tools to make significant progress on statistical seismic imaging: expertise in geophysics, applied math, and high performance computing are needed. The principal investigators have expertise in these areas. The research has the potential of improving societally important environmental/geotechnical investigations as well as more fundamental research on the structure and tectonics of the Earth's crust.

协作研究：CMG研究：统计地震成像。莱万德（W.W.） Symes，S。Minkoffboth晶体外壳和浅层表面（100m深度）环境是复杂的，机械异质的区域，通常具有机械性能的空间分布，这些特性与相对平滑的层状沉积物柱截然不同。探索地震学目前是探索地下的最重要手段之一：用于沉积柱中的石油，用于浅层地下的岩土/环境目的，以及了解结晶壳中的构造过程。 石油行业的反思地震学是为了探索沉积柱的开发，即，介质是分层的，能量优势单独散布，尺度是二分法。它在近地表环境和深层地壳中的应用非常成功，但也出现了石油探索中通常不会遇到的问题。 近表面经过化学和机械风化过程，产生高度异质的非层培养基。由于压实，化学改变以及水的存在或不存在，机械性能可以在几个波长内的数量级变化。晶体外壳虽然缺乏机械性能的数量级变化，但在空间上具有复杂的，通常是自动（分形）的地震速度和密度异质性的分布。对于地壳中相对较长的路径传播，波场通常属于强大的散射状态，在这种方案中，线性成像系统将产生平庸或荒谬的结果。这项研究计划迈出了对复杂媒体的互补成像范式的第一步，该媒体对复杂媒体进行了统计震荡的统计震荡成像，在使用统计范围的统计范围内构图了统计范围，以统计范围绘制了统计范围。 由于这是一个非常大的话题，因此提案范围将仅限于一些努力。该研究将探讨（1）将亚波长度量表异质性与宏观尺度传播效应（有效的机械性能，速度，衰减，分散等）相关的有效模型，（2）多次反射和折射的程度可以区分及其对传统地震成像的影响，以及（3）识别强度均匀的差异。 该研究涉及高水平的软件开发和计算工作，包括3D地震模拟和材料属性和统计数据的非线性反转。没有一学科拥有在统计地震成像上取得重大进展的工具：需要地球物理，应用数学和高性能计算方面的专业知识。 主要研究人员在这些领域具有专业知识。 该研究具有改善社会重要的环境/岩土技术研究，以及对地壳结构和构造的更基本研究。