CSEDI: Collaborative Research: Observational and Theoretical Constraints on the Structure and Rotation of the Inner Core

本合作项目的主要目标有两个：(1)通过提出的pascal实验获得高分辨率的内核各向异性图像；(2)建立地震各向异性成因的地球动力学模型。研究人员计划在阿拉斯加内陆部署两个由15个新站点组成的线性阵列，编码为阿拉斯加内核（北极）接收交叉横断面。从南桑威奇群岛地震到阵列的新数据将为确定内核旋转和解决内核过渡带结构以及内核各向异性和衰减的深度依赖提供急需的内核横向和深度样本。该团队计划利用新的和现有的数据作为约束，开发一个各向异性形成的地球动力学模型。建模的主要目的是识别和研究物理过程，包括塑性变形、内核生长和再结晶以及热导率的各向异性的影响，这些都可以解释观察到的深度和各向异性的横向变化。开发的模型将作为解释地震观测的物理背景。模型的预测将用于计算合成波形，然后将其与观测结果进行比较，以改进模型。收集到的新数据还将用于阐明阿拉斯加内部的地壳和上地幔结构。从费尔班克斯到普拉德霍湾的南北线将穿过阿拉斯加北部的布鲁克斯山脉，而费尔班克斯和诺姆之间的东西线将覆盖阿拉斯加西部的部分地区，这是一个已知的、但几乎没有研究过的伸展构造区域。

The major goals of this collaborative project are two-fold: (1) To obtain high resolution images of inner core anisotropy, through a proposed PASSCAL experiment; (2) To develop a geodynamic model for the origin of the observed seismic anisotropy. The investigators plan to deploy two linear arrays of 15 new stations in the interior of Alaska, coded as Alaska Receiving Cross-Transects for the Inner Core (ARCTIC). New data from earthquakes in South Sandwich Islands to the arrays will provide critically needed lateral and depth samples of the inner core for determining the inner core rotation and for resolving the structure of the inner core transition zone and the depth-dependence of inner core anisotropy and attenuation. the team plans to develop a geodynamic model for the formation of anisotropy, using the new and existing data as a constraint. The major objective of the modeling is to identify and investigate physical processes, including effects of plastic deformation, inner-core growth and recrystallization, and anisotropy in the thermal conductivity, that can account for the observed depth and lateral variations in anisotropy. The developed model will serve as a physical context for interpreting the seismic observations. Predictions of the model will be used to calculate synthetic waveforms, which are subsequently compared with the observations to refine the model. The new data collected will also be used to elucidate crustal and upper mantle structure of the Alaska interior. The north-south line from Fairbanks to Prudhoe Bay will cross the Brooks Range in northern Alaska, and The east-west line between Fairbanks and Nome will cover parts of western Alaska in a known, but nearly unstudied, region of extensional tectonics.