CSEDI Collaborative Research: Anelastic properties of the Earth from seismic to tidal timescale

CSEDI 合作研究：从地震到潮汐时间尺度的地球滞弹性特性

• 批准号: 1464025
• 负责人: Gordana Garapic
• 金额: $ 6.38万
• 依托单位: SUNY College at New Paltz
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-01 至 2019-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1464025&HistoricalAwards=false
• 关键词: CSEDI; Collaborative; Research; Anelastic; properties

Earthquakes produce sound waves that travel through the interior of the Earth and thereby sample the conditions along their paths. Collections of large numbers of arriving sound waves are used to reconstruct conditions and structure of the interior of the Earth. While traveling through the interior, these waves produce microscopic strains in the rocks they pass through. The response of the rocks to these strains depends on conditions such as temperature and chemical environment. Very large Earthquakes in subduction zones, for example the Andaman-Sumatra earthquake from 2004 or the Alaskan earthquake from 1964, produce enough energy for the Earth to "ring like a bell". Gravitational interaction of the Earth with the Moon and the Sun (tides) causes periodic deformation of the whole Earth that is comparable to the effects of large Earthquakes. Microscopic strains similar to those caused by earthquakes and tides can be investigated in the laboratory, and thereby also the effects of temperature and chemical environment on the response. The challenge of the proposed work is to apply the laboratory results to global observations from seismology and geodesy. The promise of this approach is to improve our understanding of the conditions in the interior of the Earth and its physical description. The findings will have implications for modeling of the ongoing rebound of the surface of the Earth since the last ice age, affecting determination of the causes of changes in sea level, as well as tidal modeling of other planets and moons.The investigators propose to combine observations of small-strain deformation at a broad range of timescales, from seismic body waves (seconds) to normal modes (minutes - hour) and tides (hours to years), to determine the frequency dependence of energy dissipation in the interior of the Earth. These observations will be combined in a normal mode/tidal model of a non-spherical Earth that includes anelasticity. Results from this model will be compared to laboratory-derived models for anelastic behavior of crystalline grains and their defects, which are the basis for predictions outside of the experimentally accessible parameter space. Comparison of experimental predictions with global models will help to constrain the applicability of the microphysical models to small-strain deformation due to seismic waves and tides, and ultimately also post-glacial rebound and (large-strain) convection. At the same time the combination of information from normal modes and tides will yield new constraints on the conditions and structure in the mid to lower mantle, which are difficult to obtain by other means.

地震会产生声波，这些声波穿过地球内部，从而采样沿其路径的条件。大量到达声波的集合用于重建地球内部的条件和结构。在穿过内部时，这些波浪在它们通过的岩石中产生了微观菌株。岩石对这些菌株的反应取决于温度和化学环境等条件。俯冲带的非常大的地震，例如2004年的安达曼 - 苏马底拉地震或1964年的阿拉斯加地震，为地球提供了足够的能量，可以像铃铛一样响起。地球与月球和太阳（潮汐）的重力相互作用会引起整个地球的周期性变形，与大地震的影响相当。可以在实验室研究与地震和潮汐引起的微观菌株，从而在实验室中研究温度和化学环境对反应的影响。拟议工作的挑战是将实验室结果应用于地震学和大地测量的全球观察结果。这种方法的承诺是提高我们对地球内部条件及其物理描述中条件的理解。这些发现将对自上次冰河时代以来持续的地球表面反弹的建模产生影响，这影响了确定海平面变化的原因，以及对其他行星和月亮的潮汐建模。研究人员提议结合在时间上（seisis times and seisis times and secess and secons）（秒）（秒）（秒）（秒）（秒）（秒）（秒）（秒数）（秒）（秒数）（秒数）（秒）（秒）（分别）（秒）（分别）（秒数）（分小时）（秒数）（能量耗散在地球内部的频率依赖性。这些观察结果将在包括厌氧性的非球场地球的正常模式/潮汐模型中组合在一起。该模型的结果将与实验室衍生的模型进行比较，该模型的晶粒弹性行为及其缺陷，这是在实验可访问的参数空间之外进行预测的基础。实验预测与全球模型的比较将有助于限制微物理模型由于地震波和潮汐而导致的小型构造变形的适用性，并最终也最终在冰川后反弹和（大型）对流。同时，来自正常模式和潮汐的信息的组合将对中陆壁台的条件和结构产生新的约束，这些条件和结构很难通过其他方式获得。