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EAR-PF: Investigating the lithospheric structure and the origins of seismic anomalies in the Southwestern United States using a joint seismic analysis

EAR-PF：利用联合地震分析研究美国西南部的岩石圈结构和地震异常的起源

基本信息

批准号：
1952725
负责人：
Eva Golos
金额：
$ 17.4万
依托单位：
Golos, Eva
依托单位国家：
美国
项目类别：
Fellowship Award
财政年份：
2020
资助国家：
美国
起止时间：
2020-08-01 至 2022-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1952725&HistoricalAwards=false
关键词：
EAR PF Investigating lithospheric structure

项目摘要

An EAR Postdoctoral fellowship has been awarded to Dr. Eva Golos to carry out research and education plans at Brown University under the mentorship of Professor Karen Fischer. She aims to understand the structure and evolution of the lithosphere under the southwestern United States by integrating information from different types of seismic waves. The research will focus on how various factors such as temperature, rock composition, and melting control the structure and strength of the present-day lithosphere, and how this interplay has guided tectonic evolution over geologic time scales. Dr. Golos will develop a new inversion method using a variety of seismic data, including surface waves, seismic waves that traverse the lithosphere, and those that have been reflected or converted from one type of seismic wave to another. The combination of input data will produce models with more resolution. Interpretation of the resulting seismic model will be carried out alongside forward-modeling of the effects of melt and anisotropy (the dependence of the speed of seismic wave propagation on vibration direction). Information from a number of scales must be synthesized from the grain-scale to sharp discontinuities in the mantle to the entire depth extent of the lithosphere. The findings will yield insight into how lithospheric properties affect deformation and surface dynamics, with implications for natural hazards such as earthquakes and volcanoes. These applications provide a natural starting point for outreach activities, which will be done through programs aimed at elementary school audiences as well as through teaching and undergraduate mentoring.Many unanswered questions pertain to the nature of the continental lithosphere, and particularly the relative roles of temperature, compositional variations, anisotropic structures, and the presence and abundance of partial melt. This work aims to understand these factors and their effects on lithospheric structure, thickness, and strength; on deformation and the response at the surface to tectonic forces; and on the evolution and fate of the continental lithosphere. The southwestern United States will be used as a case study, to probe the origins of geophysical anomalies associated with the Colorado Plateau, Basin and Range Province, and Rio Grande Rift. The approach taken will be two-pronged. First, a seismic model will be developed incorporating a variety of networks including the USArray Transportable Array, Earthscope FlexArray deployments, and permanent broadband stations. A model of shear wavespeed and discontinuity structure will be generated through a Bayesian inversion of a plethora of seismic data, including P-to-s and S-to-p receiver functions, Rayleigh wave phase velocity dispersion, and body wave reflectivity autocorrelograms. The complementary nature of these data will help resolve smooth large-scale features as well as sharp boundaries and discontinuities. Variations in receiver functions at different frequency bands, and from different directions, can be used to infer the sharpness and the anisotropic properties of interfaces, respectively. The second part of this investigation involves using forward modeling to estimate the relative effects of thermal, compositional, and melt-related properties on seismic structure, and to provide constraints on their interplay at regional-to-continental scales. This project was funded jointly by the Geophysics program in the Division of Earth Sciences and the Established Program to Stimulate Competitive Research (EPSCoR) office.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.

伊娃戈洛斯博士被授予博士后研究金，在凯伦·菲舍尔教授的指导下在布朗大学开展研究和教育计划。她的目标是通过整合来自不同类型地震波的信息来了解美国西南部岩石圈的结构和演化。研究将集中在各种因素，如温度，岩石成分和熔融控制的结构和强度的现今岩石圈，以及这种相互作用如何引导地质时间尺度的构造演化。Golos博士将开发一种新的反演方法，使用各种地震数据，包括表面波，穿越岩石圈的地震波，以及那些从一种类型的地震波反射或转换到另一种类型的地震波。输入数据的组合将产生具有更高分辨率的模型。将对所产生的地震模型进行解释，同时对融化和各向异性的影响（地震波传播速度对振动方向的依赖性）进行正演模拟。从地幔中的颗粒尺度到岩石圈的整个深度范围，必须综合来自多个尺度的信息。这些发现将深入了解岩石圈特性如何影响变形和表面动力学，并对地震和火山等自然灾害产生影响。这些应用为推广活动提供了一个自然的起点，这将通过针对小学观众的计划以及通过教学和本科生辅导来完成。许多未回答的问题涉及大陆岩石圈的性质，特别是温度的相对作用，成分变化，各向异性结构，以及部分熔融的存在和丰度。这项工作的目的是了解这些因素及其对岩石圈的结构，厚度和强度的影响;变形和在地面构造力的反应;和大陆岩石圈的演化和命运。美国西南部将作为一个案例研究，探讨与科罗拉多高原，盆地和山脉省，和格兰德河裂谷地球物理异常的起源。所采取的办法将是双管齐下的。首先，将开发一个地震模型，其中包括各种网络，包括USAray便携式阵列，Earthscope FlexArray部署和永久宽带站。剪切波速度和不连续结构的模型将通过大量地震数据的贝叶斯反演生成，包括P-to-s和S-to-p接收器函数、瑞利波相速度色散和体波反射率自相关图。这些数据的互补性将有助于解决平滑的大规模特征以及尖锐的边界和不连续性。在不同的频带，并从不同的方向，接收器功能的变化，可以用来推断的清晰度和各向异性性能的接口，分别。本次调查的第二部分涉及使用正演模拟来估计地震结构的热，成分和熔融相关的属性的相对影响，并提供在区域到大陆尺度上的相互作用的限制。该项目由地球科学部的地球物理学项目和激励竞争性研究的既定项目（EPSCoR）办公室共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。