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

该项目应用了最近开发的三维直接波场成像方法来处理地球镜可移动阵列（TA）数据。该方法应用了一系列实现三维偏移反演的算法。以类似于地震反射处理的方式对TA记录的体波的三分量波形进行处理，以产生大陆下P到S散射强度的三维图像体积。该方法被用于生成Juan de Fuca/Farallon系统俯冲岩石圈的高分辨率图像，并开发该系统的三维几何模型。当阵列向东移动时，该方法将被用来成像岩石圈尺度的边界，可以应用于测试大陆前寒武纪核心如何组装的模型。改进这种新方法的技术问题是：(1)将方法扩展到图像S到P转换，(2)估计介质脉冲响应的新方法（反褶积），(3)改进无源阵列规范的不规则数据处理，(4)改进误差评估指标，(5)多次去除。更广泛的影响包括支持博士生的研究和通过网络提供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.