Collaborative Research: Developing a Three-Dimensional Seismic Reference Earth Model (REM-3D) in Collaboration with the Community

合作研究：与社区合作开发三维地震参考地球模型 (REM-3D)

• 批准号: 1345103
• 负责人: Barbara Romanowicz
• 金额: $ 5万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-01 至 2018-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1345103&HistoricalAwards=false
• 关键词: Collaborative; Research; Developing; Three; Dimensional

Elastic properties of the Earth's interior (e.g. density, rigidity, compressibility, etc.) vary with location due to changes in temperature, pressure, composition, and flow. In the 20th century, Earth scientists have used seismic waves emitted by earthquakes and explosions to develop models of how Earth properties vary with depth. Community reference models that grew out of these efforts have proven indispensable in earthquake location, imaging of interior structure, understanding material properties under extreme conditions, and as a reference in other fields, such as particle physics and astronomy. Over the past three decades, more sophisticated efforts by seismologists across the globe have yielded several generations of models of how properties vary not only with depth, but also laterally. Yet, though these three-dimensional (3D) models exhibit compelling similarities at large scales, differences in the methodology, representation of structure, and dataset upon which they are based, have prevented the creation of 3D community reference models. The investigators propose to overcome these challenges by compiling, reconciling, and distributing a long period reference seismic dataset, from which they will construct a 3D seismic reference model (REM-3D) for the Earth's mantle. As a community reference model and with fully quantified uncertainties and tradeoffs, REM-3D will facilitate Earth imaging studies, earthquake characterization, inferences on temperature and composition in the deep interior, and be of improved utility to emerging scientific endeavors, such as neutrino geoscience. The investigators will set up community working groups that will serve to advise during the process of reference model and dataset development, and will organize a workshop to assess progress, evaluate model and dataset performance, identify avenues for improvement, and recommend strategies for maximizing model adoption in and utility for the deep Earth community. To this end, the investigators have solicited input from seismologists, mineral physicists, geodynamics, and geochemists from around the United States and internationally. The investigators propose to develop a three-dimensional seismic reference model (REM-3D) for the Earth's mantle, parameterized in terms of shear wavespeed (Vs), compressional wavespeed (Vp), density (ρ), and the 3 additional parameters representing radial anisotropy. Two versions of the model will be developed to explicitly fit the comprehensive, community-contributed long period seismic dataset, one parameterized in terms of spherical harmonics, and the other as canonical profiles corresponding to major geographic provinces. Furthermore, they will compile, reconcile, and distribute a long period reference seismic dataset, including surface wave dispersion measurements, long period absolute and differential body wave measurements, and free oscillation frequencies / attenuation / and splitting. Unlike previous reference models of Earth structure, REM-3D will have fully quantified. The investigators will also create online tools for model distribution and for predicting various seismic observables, including full waveforms, as well as tools designed primarily to enable mineral physicists and geodynamicists a straightforward way of (in)validating test models against this reference model or directly against the reference dataset. Finally, the investigators will set up community working groups and organize workshops that will advise on and evaluate model and dataset performance, identify avenues for improvement, and recommend strategies for maximizing model adoption in and utility for the deep Earth community. REM-3D will benefit the broader scientific community by facilitating: 1. Mineralogical and thermo-chemical interpretation of seismic velocities and density; 2. Identification of anomalous / atypical structures in the Earth's mantle; 3. Comparison of global and regional tomographic models; 4. Seismic waveform interpretation, such as the identification of particular seismic phases; 5. Inversion for 3D Earth structure requires a starting or background model; 6. Earthquake source characterization using long period data. The construction of a community-contributed reference dataset will make possible the identification of anomalous seismic wave travel times, surface wave dispersion, normal mode splitting, and waveform features. Furthermore, the tools for predicting seismic observables from input structures that we will create will enable direct evaluation of potential velocity structures predicted by mineral physics and geodynamics experiments and calculations.

地球内部的弹性特性（例如密度，刚度，可压缩性等）随着温度，压力，组成和流动而变化而变化。在20世纪，地球科学家使用地震发出的地震波和爆炸来开发地球性质如何随深度变化的模型。从这些努力中发展出来的社区参考模型已证明在地震位置，室内结构的成像，在极端条件下理解材料特性以及作为其他领域的参考，例如粒子物理和天文学。在过去的三十年中，全球地震学家的更复杂的努力产生了几代模型，不仅与深度，而且横向不同。然而，尽管这些三维（3D）模型在大尺度上表现出引人注目的相似性，但它们所基于的方法，结构的表示和数据集的差异已阻止创建3D社区参考模型。研究人员建议通过编译，调和和分发长期参考地震数据集来克服这些挑战，他们将为地球的地幔构建一个3D地震参考模型（REM-3D）。作为一个社区参考模型，并具有完全量化的不确定性和权衡，REM-3D将促进地球成像研究，地震表征，对深层内部的温度和组成的推论，并改善了对新兴的科学努力的实用性，例如中微子地球科学。调查人员将建立社区工作组，这些工作组将在参考模型和数据集开发过程中为建议提供建议，并将组织一个研讨会来评估进度，评估模型和数据集绩效，确定改进的途径，并推荐最大化地球社区模型的模型和实用性的策略。为此，研究人员征求了来自美国和国际上的地震学家，矿物质学家，地球动力学和地球化学家的意见。研究人员建议为地球地幔开发一个三维地震参考模型（REM-3D），以剪切波（VS）（VS），压缩波（VP）（VP），密度（＆＃961;）和代表径向径向异位素的3个附加参数进行参数化。该模型的两个版本将被开发，以明确符合综合的，社区的长期地震数据集，一个用球形谐波进行了参数，另一个是与主要地理省相对应的规范概况。此外，它们将编译，调和和分发长期参考地震数据集，包括表面波分散测量，长期绝对和差异的身体波测量以及自由振荡频率 /衰减 /拆卸频率和拆卸。与以前的地球结构参考模型不同，REM-3D将完全量化。研究人员还将创建用于模型分布的在线工具，并预测包括完整波形在内的各种地震可观察物，以及设计主要旨在使矿物物理学家和地球动力学家的工具直接（IN）在（IN）对此参考模型验证测试模型或直接针对参考数据集的方式。最后，调查人员将建立社区工作组并组织研讨会，以建议和评估模型和数据集绩效，确定改进的途径，并建议采用最大化模型采用的策略，并为深层地球社区提供实用性。 REM-3D将通过促进：1。对地震速度和密度的矿物学和热化学解释来使更广泛的科学界受益； 2。鉴定地球地幔中异常 /非典型结构； 3。全球和区域层析成像模型的比较； 4。地震波形解释，例如特定地震阶段的识别； 5。对3D地球结构的反转需要起始模型或背景模型； 6。使用长期数据进行地震源表征。 社区成员参考数据集的构建将使您可以识别异常的地震波行进时间，表面波散分散，正常模式分裂和波形特征。此外，从我们将创建的输入结构中预测可观察到的可观察到的工具将能够直接评估矿物物理学和地球动力学实验和计算所预测的潜在速度结构。