Mantle Dynamics of the Izu-Bonin Subduction System

伊豆-小笠原俯冲系统的地幔动力学

• 批准号: 0305564
• 负责人: Matthew Fouch
• 金额: $ 11.49万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2005-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0305564&HistoricalAwards=false
• 关键词: Mantle; Dynamics; Izu; Bonin; Subduction

This study provides new constraints on mantle flow and dynamics within the Izu-Bonin subduction system through a combination of seismic observations and numerical modeling experiments. Results of this work are providing key information regarding mantle processes in convergent margins, including the means of mantle magma transport and the geometry of strain partitioning between tectonic plates and the sublithospheric mantle.In this coupled approach, the following issues are being addressed specifically: 1) the 3-D distribution of upper mantle anisotropy and its implications for strain partitioning and mantle flow in the Izu-Bonin subduction zone; and 2) the interpretation of seismic anisotropy results, particularly their relationship to both mantle transport processes and the degree of coupling between tectonic plates and sublithospheric mantle.The seismic component of the project involves shear wave splitting analysis for a unique set of shear phases, including local S, teleseismic SKS, and sS-S differential splitting. The Izu-Bonin region is particularly well-suited for the proposed seismic studies, as earthquakes generated in Izu-Bonin provide an excellent dataset of seismic phases that sample a broad portion of the study area. The availability of broadband waveforms of Izu-Bonin earthquakes have been recorded by many high-resolution seismographs and allows constraint of both lateral variations and the depth distribution of anisotropy for the Izu-Bonin system. The numerical modeling component of the project involves calculation of 3-D models of mantle flow for a range of physical model parameters. To determine the relationship of mantle flow to the seismic anisotropy observations, flow models are being used to calculate predicted anisotropy using appropriate elastic parameter values from a range of deformation studies, and comparing the modeling results with the seismic anisotropy results.

这项研究通过地震观测和数值建模实验的结合，对IZU-BONIN俯冲系统内地幔流和动态的新限制提供了新的限制。 这项工作的结果提供了有关收敛余量中地幔过程的关键信息，包括地幔岩浆运输的手段以及构造板和跨石层地幔之间的应变分配的几何形状。在这种耦合方法中，以下问题进行了特定问题：1）应对上层抗体的3-d分配和含量分配的含量，并构成了分配的含量，并构成了MON的含量分配，并构成了MON的含量分配。区域； 2）地震各向异性结果的解释，尤其是它们与地幔传输过程的关系，以及构造板和sublithosphicher santle之间的耦合程度。该项目的地震组成部分涉及用于剪切波拆分分析，用于一组独特的剪切阶段，包括本地S，伸缩式Sks和Sss sss sss sss sss sss sss sss sss sss sss sss sss spectition。 Izu-Bonin区域特别适合拟议的地震研究，因为Izu-Bonin在Izu-Bonin中产生的地震提供了一个极好的地震阶段数据集，这些阶段的数据集采样了研究区域的大部分。 许多高分辨率地震仪记录了Izu-Bonin地震的宽带波形的可用性，并允许对Izu-Bonin系统的侧向变化和各向异性的深度分布的限制。项目的数值建模组件涉及计算一系列物理模型参数的3-D模型。 为了确定地幔流与地震各向异性观测的关系，使用来自一系列变形研究的适当弹性参数值来计算预测的各向异性，并将建模结果与地震性各向异性各向异性结果进行比较。