The exact mechanism for lowermost mantle seismic anisotropy remains unknown; however, work on the elasticity and deformation of lower mantle materials has constrained a few possible options. The most probable minerals producing anisotropy are bridgmanite, postperovskite, and ferropericlase. While there is an extensive literature on the elasticity and deformation of lower mantle minerals, we create a comprehensive uniform database of D″ anisotropy scenarios. In order to characterize a range of the possible fabrics for D″ anisotropy, we carry out VPSC (visco‐plastic self‐consistent modeling) to predict textures for each proposed mineral and dominant slip system. We numerically deform each mineral under different geometrical scenarios: simple shear, pure shear, and extension. By using published single crystal elasticity values, we produce a library of 336 candidate elastic tensors. We used the elastic tensor library to revisit previously published D″‐associated seismic anisotropy studies for crossing raypaths (Siberia, North America, the Afar region of Africa, and Australia). While we cannot identify a single, unique mechanism that explains all of these data sets, we find that postperovskite (dominant slip on [100](010) or [100](001)) and periclase (dominant slip on {100}<011>) provide the best fit to the observations and suggest reasonable shear directions for each region of interest. Bridgmanite generally provides a poor fit to the observations; however, we cannot completely rule out any particular model. As the number of anisotropy observations for D″ increases, this elastic tensor library will be helpful for observational seismologists in identifying possible mechanisms of anisotropy and shear directions at in the lowermost mantle.

中文翻译：

---

用于最低地幔地震各向异性研究的弹性张量库以及与地震观测值的比较

最低地幔地震各向异性的确切机理尚不清楚；然而，有关下地幔材料的弹性和变形的研究限制了一些可能的选择。产生各向异性的最可能矿物是桥锰矿，钙钛矿和铁镁锰矿。虽然有大量有关下地幔矿物的弹性和变形的文献，但我们创建了D ”各向异性情况的综合统一数据库。为了表征D可能的面料范围”各向异性，我们进行了VPSC（粘塑性自洽建模）来预测每种提议的矿物和优势滑移系统的质地。我们在不同的几何场景下对每种矿物进行数字变形：简单剪切，纯剪切和延伸。通过使用已发布的单晶弹性值，我们生成了336个候选弹性张量的库。我们使用弹性张量库重新访问了先前发布的D”相关的横穿射线路径的地震各向异性研究（西伯利亚，北美，非洲的阿法尔地区和澳大利亚）。虽然我们无法确定解释所有这些数据集的单一且独特的机制，但我们发现钙钛矿后（[100]（010）或[100]（001）上的主要滑动）和周长石（{100} <011上的主要滑动） >）最适合观察结果，并为每个感兴趣的区域建议合理的剪切方向。Bridgmanite通常不适合观察。但是，我们不能完全排除任何特定模型。随着对D ''的各向异性观测数量的增加，该弹性张量库将有助于观测地震学家识别最低地幔中各向异性和剪切方向的可能机制。