A Structural and Dynamic Model of Subduction at the Middle American Trench, Central Mexico

该项目通过数值实验探索俯冲带的动态，推进俯冲带状态与其演变方式之间的概念和数量联系。动力学模型与沿中美洲海沟（MAT）的俯冲沿着。 MAT被用来约束时间依赖的模型，因为一个明确的渐进重新定位的火山弧，因为渐新世。 通过模型，现代地幔结构正与古地理学联系起来。我们的分析研究与中美洲俯冲实验（MASE）-墨西哥和美国科学家之间的一项重大国际合作相吻合。目前正在沿着一条从阿卡普尔科到坦皮科（穿过墨西哥城）的横贯墨西哥断面进行密集地震试验，并为俯冲建模提供关键参数-板块几何形状和结构，以及地幔楔粘性的地震代用指标。地球动力学模型的构建是由板块结构的显著的沿走向变化引起的，尽管沿着MAT的板块年龄和俯冲速度沿着有简单的变化。 各种各样的模型被用来研究一系列的问题（包括，平板状态是如何形成的，上板块如何抵抗平板的变形，一个年轻的板块如何具有陡峭的倾角，等等）。 结构、瞬时地球动力学和随时间变化的地球动力学模型正在被整合成一个连续的套件，其中一个模型的结果正在改善其他模型。 该项目广泛使用了新建立的加州理工学院地球科学计算设施及其2048处理器戴尔超级计算机。一些主要模式包括以下几种。第一个是地震模型。正在利用接收器功能、旅行时间衰减层析成像和全波场模拟分析地震数据，以了解地壳和板片结构以及地幔楔的粘性结构。二是瞬时地球动力学模型。动态模型被发现是一致的地震结构，热流，地形，重力和主导的水平板的拉应力与2-D和3-D粘性模型。 确定正在进行中，看看板楔和地幔楔粘度模型与这些结果是一致的。第三是古地理一致的地球动力学模型。 平板俯冲的开始和墨西哥火山活动模式的时空变化正在解决与一个球形对流模型耦合到交互式板块重建软件（GPlates）。这项研究为博士后研究员Vlad Manea提供了进一步发展他的研究事业的机会，特别是在地球动力学方面。该项目还支持培训一名地球物理学研究生。这笔用于分析MASE数据的资金正在加强美国和墨西哥科学家之间的合作。

This project is advancing the conceptual and quantitative links between the state of subduction zones and the manner in which they evolve by exploring their dynamics with numerical experiments. Dynamic models are being related to subduction along the Middle America Trench (MAT). MAT is being used to constrain time-dependent models because of a clear progressive reorientation of the volcanic arc since the Oligocene. With models, present mantle structure is being linked with paleogeography. Our analysis study coincides with the Meso-American Subduction Experiment (MASE) -- a major international collaboration between Mexican and American scientists. A dense seismic experiment is currently deployed along a trans-Mexico transect from Acapulco to Tampico (through Mexico City) and provides critical parameters for subduction modeling -- the slab geometry and structure, and seismic proxies for viscosity of the mantle wedge. Construction of the geodynamic model is motivated by significant along-strike variations in slab structure despite simple variations in plate age and subduction velocity along the MAT. A variety of models are being brought to bear on a series of questions (including, how does the flat slab regime set in, how does the upper plate resist deformation by the flat slab, how can a younger plate have a steep dip, etc.). Structural, instantaneous geodynamic, and time-dependent geodynamic models are being integrated into a continuous suite in which the results of one are improving the others. This projects makes extensive use of the newly established Caltech Geosciences Computational Facility with its 2048 processor Dell Supercomputer. Some principal models include the following. The first are seismic models. Seismic data are being analyzed for crustal and slab structure and the viscosity structure of the mantle wedge using receiver functions, travel time & attenuation tomography, and full wavefield simulations. The second are instantaneous geodynamic models. Dynamic models are being found that are consistent with seismic structure, heat flow, topography, gravity and the dominate tensile stress of the horizontal slab with 2-D and 3-D viscous models. Determinations are underway to see what slab and mantle wedge viscosity models are consistent with these results. The third are paleogeographically consistent geodynamic models. The onset of flat slab subduction and the space-time changes in the pattern of Mexican volcanism are being addressed with a spherical convection model coupled to interactive plate reconstruction software (GPlates).This study is providing the opportunity for a postdoctoral researcher, Vlad Manea, to further his research career, particularly in geodynamics. The project also supports the training of one graduate student in geophysics. This funding for analysis of MASE data is enhancing collaboration between US and Mexican scientists.