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地震 ›› 2019, Vol. 39 ›› Issue (3): 106-114.

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2013年岷县—漳县6.6级地震地磁垂直分量日变化低点时间空间分布特征

戴勇1, 高立新1, 姚丽2, 朱培育3, 格根1, 王磊1   

  1. 1.内蒙古自治区地震局, 内蒙古 呼和浩特 010010;
    2.中国地震台网中心, 北京 100045;
    3.崇明地震台, 上海 202150
  • 收稿日期:2018-07-23 出版日期:2019-07-31 发布日期:2019-08-09
  • 通讯作者: 高立新, 正研级高级工程师。 E-mail: glx_nm.email@163.com
  • 作者简介:戴勇(1981-), 男, 安徽巢湖人, 高级工程师, 主要从事数据处理及地震预测研究工作
  • 基金资助:
    震情跟踪定向工作任务(2018010401); 中国地震局地震科技星火计划项目(XH17010Y); 内蒙古自治区科技重大专项(重点地区地震预测预警技术研究开发与推广示范); 2018年度内蒙古自治区地震局局长基金课题(20182D05)

Low-point Time Spatial Distribution Characteristics of Geomagnetic Vertical Component Diurnal Variation before the 2013 M6.6 Minxian—Zhangxian Earthquake

DAI Yong1, GAO Li-xin1, YAO Li2, ZHU Pei-yu3, GE Gen1, WANG Lei1   

  1. 1.Earthquake Administration of Inner Mongolia Autonomous Region, Hohhot 010010, China;
    2.China Earthquake Networks Center, Beijing 100045, China;
    3.Chongming Seismic Station, Shanghai 202150, China
  • Received:2018-07-23 Online:2019-07-31 Published:2019-08-09

摘要: 2013年6月16日, 中国大陆西部出现地磁低点位移。 异常出现后一个月内, 位于低点位移分界线附近发生7月22日岷县、 漳县交界6.6级地震。 本文通过采用实测低点时间减去理论低点时间的方法剔除低点时间经度效应, 并以剔除经度效应后低点时间为0 h的等值线作为低点位移分界线, 2013年岷县—漳县6.6级地震震中处于6月16日地磁低点位移分界线上。 对异常期间的中国大陆地区地磁垂直分量日变形态进行统计, 发现其存在显著的分区特征, 低点时间为正的区域内日变化形态基本呈现W型, 低点时间为负的区域内日变化形态主要呈现V字型特征。 低点位移异常日期间, 中国大陆存在显著的高梯度带, 本文采用梯度值定量描述低点时间空间变化程度。 在6月13日正常日期间, 中国大陆地区未出现梯度值大于1.5 h/(°)的区域, 在6月16日异常日期间, 出现梯度值大于1.5 h/(°)的区域, 2013年岷县—漳县6.6级地震位于高梯度区边缘。

关键词: 2013年岷县—漳县6.6级地震, 地磁垂直分量, 日变化, 低点位移, 低点时间

Abstract: The geomagnetic low-point displacement appeared on June 16th, 2013. In this paper, low-point time longitude effect is eliminated by the method of subtracting theoretical low-point time from measured low-point time. The isoline with low-point time of 0 h after eliminating the longitude effect is used as the boundary of low-point displacement. The epicenter of the M6.6 Minxian—Zhangxian earthquake is at the boundary of the geomagnetic low point displacement on June 16th. The diurnal variation of geomagnetic vertical components in mainland China during abnormal periods is statistically analyzed. There are significant zoning features. The diurnal variation pattern in the area with positive low-point time presents W type, while the diurnal variation pattern in the area with negative low-point time mainly presents V type characteristics. During the abnormal period, there are significant high gradient zones in the mainland of China. In this paper, the gradient value is used to quantitatively describe the spatial and temporal variation of low-point time. During the normal period of June 13th, there is no region in the mainland of China with a gradient value greater than 1.5 h /(°). During the abnormal period of June 16th, there is area with a gradient value greater than 1.5 h/(°). The epicenter of the 2013 M6.6 Minxian—Zhangxian Earthquake is located at the edge of the high gradient region.

Key words: the 2013 M6.6 Minxian—Zhangxian Earthquake, Geomagnetic vertical component, Daily variation, Geomagnetic low-point displacement, Low-point time

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