【摘要】 在安装地震仪器时,方位精度要求到6′,而在许多台站的摆房里预先没有划好方位线,故不得不借助罗盘定向,且必须用磁偏角修正。阐述了磁偏角的变化,提出了计算磁偏角的方法,推出了实用的计算公式。更多还原

【Abstract】 Orientation,the accuracy should be 6′, for the seismic instruments is important. Because there is no orientation line in many seismic stations, people has to use the compass to find the earth’s north orientation and use the magnetic declination to correct the result. This paper describes the change of the magnetic declination and the method and the formation for calculating magnetic declination are presented as well.更多还原