Integrating the LPO Constraint into 3D Subduction Dynamics Simulations

GSTDTAP

项目编号	1620618
	Integrating the LPO Constraint into 3D Subduction Dynamics Simulations
	Magali Billen
主持机构	University of California-Davis
项目开始年	2016
	2016-07-01
项目结束日期	2019-06-30
资助机构	US-NSF
项目类别	Continuing grant
项目经费	94888(USD)
国家	美国
语种	英语
英文摘要	Subduction is the process by which one tectonic plate sinks beneath another tectonic plate into the Earth's mantle. Subduction zones are some of the most tectonically and seismically active areas on the planet. They have large destructive earthquakes and abundant volcanic activity. This geologic activity is driven by the sinking tectonic plate, which causes deformation (build up of stresses) and melting in the surrounding mantle. These subsurface processes are observed indirectly using geophysical and geochemical methods. Of these observations, only seismic anisotropy can be directly linked to the spatial pattern of deformation caused by sinking of the subducted plate. To make the link from observations of seismic anisotropy to deformation in the mantle scientists need to calculate a fabric that develops in the deformed rocks called lattice-preferred orientation (LPO). The proposed research will simulate subduction to predict the LPO structure. This is the first time LPO calculations will be fully incorporated into large-scale 3-D simulations. By analyzing these results the investigators will provide better interpretations of seismic anisotropy observation in terms of the 3-D deformation in the shallow mantle. A better understanding of the mantle deformation (stresses) is important for addressing natural hazards due to earthquakes and volcanic activity in subduction zones. All of the computational modules developed for the project will be made publicly available to advance similar studies beyond this project. The project will train a PhD student in computational modeling, analysis of complex systems and how to communicate scientific results to a broad audience. The project will also provide research opportunities for undergraduates to develop their skills in critical-thinking, project development, leadership, and the scientific method. The proposed research will create, run and analyze approximately 16, 3-D, time-dependent simulations of subduction using the mantle simulation code ASPECT, with fully-integrated calculations of the evolution of LPO structure throughout the model domain using tracer particles and a kinematic (D-Rex) LPO calculation. The models will be analyzed to identify features in the LPO structure that are related to different parameters (physical properties, geometry) defining the subduction system. They will also be analyzed to identify patterns in the LPO structure related to the phase of subduction and state of deformation in the slab. Predictions of seismic anisotropy observed at the surface will be made for a subset of models designed to match the general characteristics of the Cascadia, S. America and Middle America subduction zones. The investigators will then compare the predicted and observed seismic anisotropy to determine how the observations are related to flow in the mantle and deformation of the slab. The graduate student researcher, will be primarily responsible for creating, running, and processing simulations, as well as the analysis of the results in terms of subduction system parameters and phase/state of subduction. The PI will be primarily responsible for writing the post-processing codes that takes the LPO structure from ASPECT, calculates the elastic tensor and resulting seismic anisotropy, and for the comparison of these predictions to observations from three locations. They anticipate publication of at least six manuscripts with the major findings of the project.
来源学科分类	Geosciences - Earth Sciences
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/69731
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Magali Billen.Integrating the LPO Constraint into 3D Subduction Dynamics Simulations.2016.