Physical properties of deep subducted lithosphere

深俯冲岩石圈的物理性质

• 批准号: 267461934
• 负责人: Professorin Dr. Christine Thomas
• 金额: --
• 依托单位: Institut für Geophysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/267461934?language=en
• 关键词: Physical; properties; deep; subducted; lithosphere

Subduction zones form dominant structures on Earth, and studies ofthe structure of plates at the surface of the Earth suggest that threedimensionalstructures and complexities should be found in thesesubducted plates. Tomographic inversions show that the so-calledslabs can, in several cases, descend into the deep mantle. However,direct observations of the subducted lithosphere are rare. Theseobservations, however, are important in order to study the structuraldifferences of the subducted plates as well as the differences betweendifferent regions, and to study the behavior of the subducted plateswith depth. In the first part of the project we have detected reflectionsthat deviate from the great circle path between source and receiver(out-of-plane waves) and verified their existence and origin usingsimple models including deep subduction structures. In this follow-upproject we would like to further investigate the structure andtopography of sinking lithosphere with the help of out--of-planeseismic data and array methods, and especially employ waveformmodelling of the propagation of seismic waves in Earth models withincluded subduction zones and other deep structures. The main focusis on a parameter study of the modelling of deep structures withrealistic mineralogy and shapes. The resulting out-of-plane wavesreflected at these structures can then be studied for waveform,polarity, frequency content, reflection angle and travel time. Higherresolution studies of waveform, polarity and amplitude are alsoplanned using mineral physics constraints. We want to continuethe previously tested regions and complement themwith crossing wavepaths in order to improve thevisibility of deeper structures. The main objectives of this project arethe investigation of deep subducted lithosphere and possiblysubducted crust using seismic array methods. We want to determine the physical parameters of the slabs by using waveform analysis and3D seismic modeling. By comparing results from different subductionregions we want to examine the processes leading to differentbehavior of subduction zones. Geodynamic modelling of differentsubduction scenarios and information from mineral physics will help tobetter understand the dynamics and structure of deep subductedlithospheres.

俯冲带形成了地球上的主要构造，对地球表面板块结构的研究表明，在这些俯冲板块中应该发现三维结构和复杂性。层析成像反演显示，在一些情况下，所谓的实验室可以下降到地幔深处。然而，对俯冲岩石圈的直接观测是罕见的。然而，这些观测对于研究俯冲板块的结构差异以及不同区域之间的差异，以及研究俯冲板块随深度变化的行为是非常重要的。在项目的第一部分，我们已经探测到偏离源和接收器之间大圆路径的反射（面外波），并使用包括深俯冲结构在内的简单模型验证了它们的存在和起源。在这个后续项目中，我们将借助平面外地震数据和阵列方法进一步研究下沉岩石圈的结构和地形，特别是在包含俯冲带和其他深部构造的地球模型中采用地震波传播的波形建模。主要集中在具有真实矿物学和形状的深部结构建模的参数研究。然后，可以研究这些结构反射的面外波的波形、极性、频率内容、反射角和传播时间。更高分辨率的波形、极性和振幅研究也计划使用矿物物理限制。我们想要继续之前测试的区域，并通过交叉波路来补充它们，以提高更深层次结构的可见性。该项目的主要目的是利用地震阵列方法研究深俯冲岩石圈和可能的俯冲地壳。我们希望通过波形分析和三维地震建模来确定板的物理参数。通过比较不同俯冲带的结果，我们想研究导致不同俯冲带行为的过程。不同俯冲情景的地球动力学建模和矿物物理信息将有助于更好地理解深俯冲岩石圈的动力学和结构。