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Linking Mantle Structure and Dynamics to the Landscape Evolution of the Cascadia Forearc

将地幔结构和动力学与卡斯卡迪亚前弧景观演化联系起来

基本信息

批准号：
1948961
负责人：
Joshua Roering
金额：
$ 29.81万
依托单位：
University of Oregon Eugene
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-01-01 至 2022-12-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1948961&HistoricalAwards=false
关键词：
Linking Mantle Structure Dynamics Landscape

项目摘要

This project aims to understand how mountain building processes near subduction zones (where tectonic plates descend into the earth) may be influenced by the physical state of the mantle hundreds of kilometers beneath the earth's surface. The focus of this study is on the Cascadia subduction zone, off the western United States, where variations in the landscape topography and anomalous regions deep in the earth have been observed. To better understand the deep structure, energy from distant earthquakes will be used to create 3D images. A goal of this project is to refine these images by incorporating multiple data types into a single coupled model. To understand the mountain building process, simulations will be run which predict how topography changes through time. Combining these methods, we can test what influence the deep earth has on how the overlaying landscape evolves.This project will investigate the mantle's influence on surface processes in the Cascadia subduction zone by synthesizing seismic data sets through joint inversions and performing numerical modeling of landscape evolution for southern Cascadia. This project will have three primary components. First, by jointly inverting teleseismic P and S data, physical properties of the subslab mantle will be constrained throughout Cascadia by investigating Vp/Vs ratios and testing the sensitivity to different data subsets and inversion parameters. Next, by testing and inverting data using three-dimensional anisotropic starting velocity models, our understanding of mantle flow will be merged with isotropic velocity structure to better constrain the 3D nature of flow and how it relates to the inferred physical state of the subslab. Finally, using a numerical landscape evolution model, this project will focus in on southern Cascadia to better constrain the timing and relative importance of uplift due to either subslab buoyancy or the migration of the Mendocino triple junction.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该项目旨在了解俯冲带（构造板块下降到地球内部）附近的造山过程如何受到地表以下数百公里处地幔物理状态的影响。这项研究的重点是卡斯卡迪亚俯冲带，关闭美国西部，在那里的地形地貌和异常地区的变化在地球深处已被观察到。为了更好地了解深层结构，来自遥远地震的能量将用于创建3D图像。这个项目的目标是通过将多个数据类型合并到一个耦合模型中来细化这些图像。为了了解造山过程，将进行模拟，预测地形如何随时间变化。结合这些方法，我们可以测试地球深部对上覆景观如何演变的影响。本项目将通过联合反演合成地震数据集，并对卡斯卡迪亚南部的景观演变进行数值模拟，研究地幔对卡斯卡迪亚俯冲带地表过程的影响。该项目将有三个主要组成部分。首先，通过联合反演地球化学P和S数据，通过调查Vp/Vs比值和测试对不同数据子集和反演参数的敏感性，在整个卡斯卡迪亚限制板下地幔的物理性质。接下来，通过使用三维各向异性起始速度模型测试和反演数据，我们对地幔流的理解将与各向同性速度结构合并，以更好地约束流动的3D性质以及它与子板的推断物理状态的关系。最后，使用一个数值景观演变模型，该项目将集中在南部卡斯卡迪亚，以更好地限制隆起的时间和相对重要性，由于要么底板浮力或迁移的门多西诺triplejunctions.This奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。