• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Nature >Magnetic ringing of the Earth
【24h】

Magnetic ringing of the Earth

机译：地球的磁环

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The study of Earth's core is an exacting task that involves interpreting indirect evidence. An innovative approach to understanding decadal changes in the magnetic field provides a new probe of core dynamics.rnLarge earthquakes excite wave motion throughout the Earth, causing it to ring like a bell. The resulting ground motion, measured by seismometers, provides helpful constraints on Earths internal structure through the study of its 'normal modes' - free oscillations that occur at discrete frequencies. Seismologically measurable oscillations have typical periods of a few minutes. But in work just published in Geophysical Journal International, Buffett et al. sound the Earth, in particular its core, through oscillations that have periods of decades.rnThe 'normal modes' studied by Buffett et al. are detected, not seismologically, but through the geomagnetic field. This field originates in Earth's molten, predominantly iron, core, being generated by the convection-driven fluid motions of a hydrodynamic dynamo. Global models of this field at Earth's surface have been constructed2 that cover a period going back 400 years. By assuming that Earth's mantle is at most a very weak electrical conductor, these models reveal decadal-timescale changes in the magnetic field (secular variation) at the core-mantle boundary. The changes in field are then used to probe the physics of the top of the core.
机译：对地球核心的研究是一项艰巨的任务，涉及解释间接证据。一种了解磁场年代际变化的创新方法为核心动力学提供了新的探索。大地震激发了整个地球的波动，使其像钟一样响。通过地震仪测量得到的地震动，通过研究地球的“正常模式”-在离散频率上发生的自由振荡，对地球内部结构提供了有用的约束。地震可测量的振荡通常具有几分钟的周期。但是在刚刚发表在《国际地球物理杂志》上的巴菲特等人的著作中。巴菲特等人研究的“正常模式”通过数十年的振荡来听起来地球，特别是地球的核心。不是通过地震而是通过地磁场来探测的。该场起源于地球的熔融铁芯，主要是由水动力发电机的对流驱动的流体运动产生的。已经建立了地球表面该场的全球模型2，该模型可以追溯到400年前。通过假设地球的地幔至多是非常弱的电导体，这些模型揭示了地幔边界处磁场的年代际尺度变化（长期变化）。磁场的变化随后被用来探测岩心顶部的物理性质。

著录项

  • 来源
    《Nature》 |2009年第7247期|652-653|共2页
  • 作者

    Richard Holme;

  • 作者单位

    Department of Earth and Ocean Sciences, University of Liverpool, Liverpool L69 3GP,UK;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号