Collaborative Research: Forward and inverse models of global plate motions and plate interactions

合作研究：全球板块运动和板块相互作用的正向和逆向模型

• 批准号: 1645775
• 负责人: Michael Gurnis
• 金额: $ 41万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1645775&HistoricalAwards=false
• 关键词: Collaborative; Research; Forward; inverse; models

Part 1: This is a project in which geoscientists at Caltech and mathematicians at New York University will collaborate to better understand the forces responsible for the motion of continents and those responsible for great earthquakes. This is a mathematical and modeling project that will use existing observations to infer the forces which push and pull the tectonic plates around and the forces which cause the plates to slow down-essentially the resistance or friction inside the earth. The driving forces arise from the lower temperatures associated with the cold tectonic plates when they return to the inside of the earth. The resistance comes from several sources including the strength of the tectonic plates and the friction between the tectonic plates. Beyond those simple statements, scientists do not know precisely how those forces are balanced and this gap in their understanding means that society cannot precisely forecast where great earthquakes will occur. Great earthquakes, like the one that caused the Fukushima nuclear disaster in Japan in 2011, are the most destructive of all earthquakes. By harnessing new computational methods developed by the team and using supercomputers supported by NSF and the Department of the Energy, the collaborators will bring a new level of understanding to this problem. Essentially, the team will develop what are called inverse models in which they will go from the data (like the motion of the tectonic plates) to maps showing the relative strength of different tectonic boundaries. Inverse models are powerful methods, especially in the area of big data, but they require considerable investment in new mathematical techniques, algorithms and computer software. Key for this project is that for the first time, the key aspects of the physics will be incorporated at high resolution. Besides the scientific output, a key outcome of this project will be the training of graduate students and postdoctoral scholars. They will gain enormous experience with sophisticated numerical methods, inversion & optimization methods, supercomputing technologies, and the linkage of data with numerical models. The graduate students in the respective fields of geophysics and applied mathematics are highly sought after by the research community (academia and government research laboratories) and private industry (including the hydrocarbon industry). A key outcome will also be sophisticated new computer software that will efficiently utilize the largest supercomputers supported by the government and industry and this software will be donated to the NSF-supported software center for geophysics (the Computational Infrastructure for Geodynamics, CIG) for broader distribution throughout the scientific community.-Part 2: The team will use global forward and inverse models to determine the variations in mechanical coupling in subduction zones using present day plate motions and the along strike variation in the depth of oceanic trenches. Using plate motions, they will then apply the methods to the geological past and more fully establish the dynamic link between changing plate motions and how they translate into and result from changes in subduction including plate coupling, with specific linkages to geophysical and geological observations. The models will be high resolution (e.g. locally 1 km or less where needed) and fully incorporate the extreme variations and non-linearity in viscosity between the slab and mantle, hinge zone and interface between subducting and over-riding plates. They will use mathematically rigorous and computationally robust PDE-constrained optimization and uncertainty quantification approaches to infer mechanical parameters and coupling coefficients between plates. Global plate motions are primarily driven by the negative buoyancy within subducted slabs, but beyond that statement there is much less consensus on either the relative importance of other driving forces or the strength and nature of resisting forces. The failure to reach consensus on the complete force balance of plate tectonics and mantle flow manifests itself in fundamental unanswered questions, including the causes of changes in plate motions over millions of years, the variability in occurrence of great earthquakes at subduction zones, and the thermal and tectonic evolution of the earth, for example. These processes are likely related to how the forces within a subducting slab are transmitted and resisted through the bending (hinge) zone from the slab and into the subducting plate. In this project, the team will take a new generation of plate-mantle models in which the details of plate boundaries are resolved while cast as a mathematically rigorous and computationally robust parameter estimation problem linked to key observational data sets. They will achieve a much deeper understanding on the forces driving and resisting plate motions, the formal trade-off between parameters, the variation of plate coupling between subduction zones, and the evolution of the force balance on million-year time scales. The most important broader impact will be the training of several Ph.D. students in geophysics and applied mathematics and a postdoctoral scholar. The students and post-docs will gain enormous experience with sophisticated numerical methods, inversion & optimization methods, supercomputing technologies, and the linkage of data with numerical models. The project will allow a young investigator in applied mathematics to more closely collaborate with earth scientists on critical scientific interest. At the end of the project the team will release the adjoint Rhea-II code to the community. Scientific impacts will be with the GPlates-CitcomS-Rhea linkage. The team will reach a new level of integration between dynamic flow models, plate kinematics and seismic tomography, that could have broad application in the geosciences. Their work could impact several large programs. The geodynamic hypotheses could result in predictions that could be tested with deep sea drilling under the auspices of IODP ocean drilling. The inference of the mechanical coupling along strike in subduction zones will be of significant use to better evaluate the role of geodynamic factors influencing the occurrence of great earthquakes and indirectly assist in the evaluation of seismic hazards.

第 1 部分：在这个项目中，加州理工学院的地球科学家和纽约大学的数学家将合作，更好地了解导致大陆运动和大地震的力量。这是一个数学和建模项目，将利用现有的观测结果来推断推拉构造板块的力以及导致板块减速的力——本质上是地球内部的阻力或摩擦力。当冷板块返回地球内部时，其驱动力来自与冷板块相关的较低温度。阻力来自多个来源，包括构造板块的强度和构造板块之间的摩擦。除了这些简单的陈述之外，科学家们并不确切地知道这些力量是如何平衡的，而他们理解上的这种差距意味着社会无法准确预测大地震将在哪里发生。大地震是所有地震中最具破坏性的，例如 2011 年引发日本福岛核灾难的地震。通过利用该团队开发的新计算方法并使用美国国家科学基金会和能源部支持的超级计算机，合作者将对这个问题的理解达到一个新的水平。本质上，该团队将开发所谓的逆模型，在该模型中，他们将从数据（如构造板块的运动）转换为显示不同构造边界相对强度的地图。逆模型是一种强大的方法，尤其是在大数据领域，但它们需要对新的数学技术、算法和计算机软件进行大量投资。该项目的关键在于，物理学的关键方面将首次以高分辨率纳入其中。 除了科学产出外，该项目的一个关键成果将是研究生和博士后学者的培训。他们将在复杂的数值方法、反演和优化方法、超级计算技术以及数据与数值模型的链接方面获得丰富的经验。 地球物理学和应用数学各自领域的研究生受到研究界（学术界和政府研究实验室）和私营企业（包括碳氢化合物行业）的高度追捧。一个关键成果还将是复杂的新型计算机软件，该软件将有效地利用政府和行业支持的最大超级计算机，并且该软件将捐赠给 NSF 支持的地球物理学软件中心（地球动力学计算基础设施，CIG）以进行更广泛的分发-第2部分：该团队将使用全球正向和逆向模型，利用当今的板块运动和海沟深度的沿走向变化来确定俯冲带中机械耦合的变化。然后，他们将利用板块运动，将这些方法应用于过去的地质，并更全面地建立板块运动变化之间的动态联系，以及它们如何转化为俯冲变化并产生俯冲变化，包括板块耦合，并与地球物理和地质观测有特定联系。这些模型将具有高分辨率（例如，需要时局部分辨率为 1 公里或更小），并充分考虑板片和地幔之间、铰接带以及俯冲板块和上覆板块之间界面之间粘度的极端变化和非线性。他们将使用数学上严格且计算稳健的偏微分方程约束优化和不确定性量化方法来推断板之间的机械参数和耦合系数。全球板块运动主要是由俯冲板块内的负浮力驱动的，但除此之外，对于其他驱动力的相对重要性或阻力的强度和性质，人们的共识要少得多。未能就板块构造和地幔流的完全力平衡达成共识体现在根本性的悬而未决的问题上，包括数百万年来板块运动变化的原因、俯冲带大地震发生的变化性以及地幔热力的变化。例如，地球的构造演化。这些过程可能与俯冲板块内的力如何通过弯曲（铰链）区域从板块传递并抵抗到俯冲板块有关。在这个项目中，该团队将采用新一代的板块地幔模型，其中板块边界的细节得到解决，同时被视为与关键观测数据集相关的数学上严格且计算稳健的参数估计问题。他们将对驱动和抵抗板块运动的力、参数之间的形式权衡、俯冲带之间板块耦合的变化以及百万年时间尺度上的力平衡的演变有更深入的了解。最重要的更广泛的影响将是培养几位博士。地球物理学和应用数学专业的学生和博士后学者。学生和博士后将在复杂的数值方法、反演和优化方法、超级计算技术以及数据与数值模型的链接方面获得丰富的经验。 该项目将使应用数学领域的年轻研究者能够在关键科学兴趣上与地球科学家更密切地合作。项目结束时，团队将向社区发布附带的 Rhea-II 代码。科学影响将通过 GPlates-CitcomS-Rhea 联系产生。 该团队将在动态流动模型、板块运动学和地震层析成像之间达到新的集成水平，这可能在地球科学中具有广泛的应用。 他们的工作可能会影响几个大型项目。地球动力学假设可以得出预测，并可以在 IODP 海洋钻探的支持下通过深海钻探进行测试。俯冲带沿走向力学耦合的推断对于更好地评价地球动力因素影响大地震发生的作用、间接辅助地震危险性评价具有重要意义。

项目成果

Subduction Duration and Slab Dip

• DOI: 10.1029/2019gc008862
• 发表时间: 2020-04-01
• 期刊: GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
• 影响因子: 3.5
• 作者: Hu, Jiashun;Gurnis, Michael
• 通讯作者: Gurnis, Michael

Reconstruction of the Cenozoic deformation of the Bohai Bay Basin, North China

• DOI: 10.1111/bre.12470
• 发表时间: 2020-05
• 期刊: Basin Research
• 影响因子: 3.2
• 作者: Yinbing Zhu;Shaofeng Liu;Bo Zhang-;M. Gurnis;P. Ma

East African topography and volcanism explained by a single, migrating plume

东非地形和火山活动由单一的迁移羽流解释

• DOI: 10.1016/j.gsf.2020.01.003
• 发表时间: 2020
• 期刊: Geoscience Frontiers
• 影响因子: 8.9
• 作者: Hassan, Rakib;Williams, Simon E.;Gurnis, Michael;Müller, Dietmar
• 通讯作者: Müller, Dietmar

Constraining absolute plate motions since the Triassic

自三叠纪以来限制绝对板块运动

• DOI: 10.1029/2019jb017442
• 发表时间: 2019
• 期刊: Journal of geophysical research
• 作者: Tetley, M.G.

Contrasted East Asia and South America tectonics driven by deep mantle flow

• DOI: 10.1016/j.epsl.2019.04.025
• 发表时间: 2019-07
• 期刊: Earth and Planetary Science Letters
• 影响因子: 5.3
• 作者: Ting Yang;Louis Moresi;M. Gurnis;Shaofeng Liu;D. Sandiford;S. Williams;F. Capitanio