Collaborative Research: Investigation of Sources of Intraplate Volcanism Using PASSCAL Broadband Instruments in Madagascar, The Comores, and Mozambique (MACOMO)

合作研究：使用 PASSCAL 宽带仪器调查马达加斯加、科摩罗和莫桑比克的板内火山活动来源 (MACOMO)

• 批准号: 0838426
• 负责人: Michael Wysession
• 金额: $ 72.54万
• 依托单位: Washington University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-10-01 至 2015-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0838426&HistoricalAwards=false
• 关键词: Collaborative; Research; Investigation; Sources; Intraplate

This project will involve the acquisition and analysis of seismic data from a network of broadband seismometers installed in Madagascar, the Comores Islands, and Mozambique in order to determine the origin of intraplate volcanism in the region. No modern seismic investigation of Madagascar, the world?s 4th largest island, has ever been made, and the source of the volcanism, not near any plate boundary, is unknown. This study seeks to determine if the volcanism is connected with either the giant lower mantle large low-shear velocity province (LLSVP) or with any of the upper mantle hot spots such as those beneath Afar or Reunion. The seismometers, borrowed from the IRIS PASSCAL pool of instruments, will be deployed in two installations: 18 in the summer of 2011 (in Madagascar, the Comores, and Mozambique), and 15 in the summer of 2012 (all in Madagascar). All seismometers will be retrieved in the summer of 2013. The broadband seismic data will be analyzed using several techniques in order to determine the sub-surface structure of the region. Both surface and body wave data will be use to generate 3D tomographic images of the crust and mantle; shear-wave splitting will be used to examine anisotropic fabric; P-to-S-wave conversions will be used to generate receiver functions for determining topography on the Moho and other sub-surface discontinuities. The African LLSVP is the largest seismic anomaly within the earth; as an enormous thermochemical boundary layer between the mantle and core, it plays a vitally important role in controlling the nature of vertical mass flux within the mantle, and therefore of both mantle convection and its manifestation at the surface as plate tectonics. The African LLSVP is thought to play an important role in the abundant occurrence of hot spot volcanism on the African plate, but the mechanism by which this occurs is not known due to the extremely limited data sampling available at this location in the Southern Hemisphere. Further study of the sub-African LLSVP will be of interest to earth scientists in many disciplines, as will providing the first study of the sub-surface geology of Madagascar. This project will help in the training of U.S. graduate students as well as scientists in Madagascar and Mozambique, and will help strengthen the scientific ties between these three countries. This project will also be a scientific partner with AfricaArray, which has been a unifying positive force of science and good will in Africa.This award is co-funded by NSF's Office of International Science and Engineering.

该项目将涉及从安装在马达加斯加、科摩罗群岛和莫桑比克的宽带地震仪网络采集和分析地震数据，以确定该地区板内火山活动的起源。世界第四大岛屿马达加斯加从未进行过现代地震调查，而且不靠近任何板块边界的火山活动来源也不得而知。这项研究旨在确定火山活动是否与巨大的下地幔大低剪切速度省（LLSVP）或任何上地幔热点（例如阿法尔或留尼汪岛下方的热点）有关。 这些地震仪取自 IRIS PASSCAL 仪器库，将分两次部署：2011 年夏天安装 18 个（马达加斯加、科摩罗和莫桑比克），2012 年夏天安装 15 个（全部安装在马达加斯加）。所有地震仪将于 2013 年夏季取回。将使用多种技术分析宽带地震数据，以确定该地区的地下结构。表面波和体波数据将用于生成地壳和地幔的 3D 断层扫描图像；剪切波分裂将用于检查各向异性织物； P 波到 S 波的转换将用于生成接收器函数，用于确定莫霍面和其他地下不连续面的地形。非洲 LLSVP 是地球上最大的地震异常；作为地幔和地核之间巨大的热化学边界层，它在控制地幔内垂直质量通量的性质方面发挥着至关重要的作用，因此也控制着地幔对流及其在表面的板块构造表现。非洲LLSVP被认为在非洲板块热点火山活动的大量发生中发挥了重要作用，但由于南半球该地点可获得的数据极其有限，其发生的机制尚不清楚。对非洲以下 LLSVP 的进一步研究将引起许多学科的地球科学家的兴趣，就像对马达加斯加地下地质学的首次研究一样。该项目将有助于培训美国研究生以及马达加斯加和莫桑比克的科学家，并将有助于加强这三个国家之间的科学联系。该项目还将与 AfricaArray 成为科学合作伙伴，AfricaArray 一直是非洲科学和善意的积极统一力量。该奖项由美国国家科学基金会国际科学与工程办公室共同资助。