What are the seismic expressions of deep thermal and thermochemical plumes?

深部热羽流和热化学羽流的地震表达是什么？

基本信息

批准号：
1565511
负责人：
Jeroen Ritsema
金额：
$ 19.42万
依托单位：
Regents of the University of Michigan - Ann Arbor
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2016
资助国家：
美国
起止时间：
2016-04-01 至 2020-03-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1565511&HistoricalAwards=false
关键词：
What seismic expressions deep thermal

项目摘要

Hawaii and Iceland are classic examples of volcanic islands associated with dynamical upwellings (i.e., plumes) from the deep mantle. Plumes form naturally and abundantly in laboratory simulations of Earth convection. Yet, there is no consensus among Earth scientists whether rising plumes exist in the Earth. The burden is on seismologists to find expressions of plumes in seismic data. This proposal is aimed at identifying how physically plausible thermal and thermochemical plumes may perturb seismic waves and how these perturbations can be found in seismic data. The project will support one PhD student. The research expands an ongoing international collaboration that provides important international experience to the PhD student at Michigan and the two students in Europe who are directly involved in the project.This proposal leverages significant investments made by the NSF in observational geophysics (including EarthScope and dedicated seismic arrays) by using the available data and providing a new, interdisciplinary investigation into the resolvability of mantle plumes by observational geophysics.By combining multidisciplinary expertise, the work in this proposal will develop high-resolution simulations of plume formation and plume morphology and it will quantify the expected plume signatures in seismic data. The research involves computer simulations of thermal and thermochemical plume ascent, mineral physics calculations of the seismic wave speed variations within plumes, and 3D simulation of the distortion of the seismic wave field by plumes. Waveform and traveltime tomography and receiver function analysis of simulated waveforms will demonstrate how plumes are imaged tomographically and whether they produce observable deflections of phase boundaries in the transition zone.

夏威夷和冰岛是与深部地幔动力上升流（即羽流）相关的火山岛的典型例子。在地球对流的实验室模拟中，羽流自然而丰富地形成。然而，地球科学家对于地球上是否存在上升的羽流尚未达成共识。地震学家的责任是在地震数据中找到羽流的表达。该提案旨在确定物理上合理的热和热化学羽流如何扰动地震波以及如何在地震数据中发现这些扰动。该项目将支持一名博士生。该研究扩大了正在进行的国际合作，为密歇根州的博士生和直接参与该项目的两名欧洲学生提供了重要的国际经验。该提案利用了 NSF 在观测地球物理学（包括 EarthScope 和专用地震）方面的重大投资阵列）通过使用现有数据，并通过观测地球物理学对地幔柱的可解析性进行新的跨学科研究。通过结合多学科专业知识，本提案中的工作将开发地幔柱形成和地幔柱的高分辨率模拟形态并将量化地震数据中预期的羽流特征。该研究涉及热和热化学羽流上升的计算机模拟、羽流内地震波速度变化的矿物物理计算以及羽流对地震波场扭曲的 3D 模拟。波形和走时断层扫描以及模拟波形的接收器函数分析将演示如何对羽流进行断层扫描成像，以及它们是否在过渡区产生可观察到的相边界偏转。