The 3-D seismic signature of plumes: wavefield effects and experiment optimization

大型地幔柱的详细地震成像是了解地幔对流和地幔地球化学演化的重要里程碑之一。到目前为止，地震研究已经发现了直径100到200公里的烟羽管道。然而，仅使用射线理论方法、简化羽流结构（如圆柱体）的（准）解析解或长周期信息（如来自表面波）来研究羽流的三维结构细节是困难的。我们建议对可能的羽状结构的完整三维波场进行广泛的研究，目的是：(1)预测频率对羽状结构振幅和波形的影响；(2)测试用于远震研究的实验配置绘制深柱结构的能力；(3)优化未来计划用于地震折射研究的实验配置；(4)开发从记录数据中提取结构信息的处理方法。三维波场的数值模拟将使用高性能计算机上开发的经过验证的算法进行，这些算法具有实现高频波场的能力。

The detailed seismic imaging of large mantle plumes is one of the major milestones towards understanding mantle convection and the geochemical evolution of the mantle. So far seismic studies have revealed plume conduits of diameter 100 to 200 km. However, details of the 3-D structure of plumes are difficult to investigate using ray-theoretical methods, (quasi-)analytical solutions for simplified plume structures (e.g. cylinders) or long-period information (e.g. from surface waves) only. We propose to carry out an extensive study of the complete 3-D wave field of likely plume structures with the aim of (1) predicting frequency-dependent effects on amplitudes and waveforms of plume-like structures; (2) testing experimental configurations for teleseismic studies on their ability to map the deep plume structure, (3) optimizing experimental configurations for seismic refraction studies planned in the future and (4) develop processing methods to extract structural information from recorded data. The numerical simulations of the 3-D wave fields will be carried out using verified algorithms developed on high-performance computers with the ability to achieve high-frequency wavefields.