Wavefield Imaging of the Mantle of North America with 3D, Plane-wave Migration

该项目正在将一种最新开发的三维直接波场成像方法应用于地球望远镜可移动阵列(TA)数据。该方法应用了一系列算法，实现了一种形式的三维偏移反演。TA记录的体波三分量波形以类似于地震反射处理的方式进行处理，以产生大陆下P到S散射强度的三维图像体。该方法被用来制作Juan de Fuca/Farallon系统俯冲岩石圈的高分辨率图像，并开发该系统几何形状的3D模型。随着阵列向东移动，该方法将用于成像岩石圈规模的边界，这些边界可用于测试大陆前寒武纪核心是如何组装的模型。为提高这种新方法的性能而面临的技术问题是：(1)将该方法扩展到成像S到P转换；(2)估计介质冲激响应(反褶积)的新方法；(3)改进对作为无源阵列标准的不规则数据的处理；(4)改进误差评估指标；(5)多次波去除。更广泛的影响包括对博士生研究的支持，以及通过网络提供3D图像卷的计划。

This project is applying a recently developed, three-dimensional, direct wavefield imaging method to Earthscope Transportable Array (TA) data. The approach applies a series of algorithms that implement a form of three-dimensional, migration inversion. Three-component waveforms of body waves recorded by the TA are manipulated in a manner similar to seismic reflection processing to produce a three-dimensional image volume of P to S scattering strength beneath the continent. The method is being used to produce high-resolution images of the subducting lithosphere of the Juan de Fuca/Farallon system and to develop a 3D model of the geometry of that system. As the array moves eastward the method will be used to image lithospheric scale boundaries that can be applied to test models of how the Precambrian core of the continent was assembled. Technical problems being attacked to improve the capabilities of this new method are: (1) extension of the method to image S to P conversions, (2) new methods for estimating the impulse response of the medium (deconvolution), (3) improved handling of irregular data that are the norm for passive arrays, (4) improved error appraisal metrics, and (5) multiple removal. Broader impacts include support for a PhD student's research and plans to make 3D image volumes available via the web.