近年地磁场的长期变特征

CHARACTERISTICS OF LONG TERM VARIATION OF GEOMAGNETIC FIELD IN RECENT YEARS

摘要: 利用红山、后土桥等台近30年的的地磁绝对观测资料, 对F、H、Z各分量进行了分析, 对Z分量的年速率进行了研究。结果:1999年和2000年F总场和Z分量长期变相继出现了转折, 结束了逐年上升的变化趋势, 但局部地区近两年有所回升。而H分量趋势没有变化, 依照原来的趋势在下降;Z分量年速率的减缓变化往往与华北地区较强地震有关。

Abstract: The F, H and Z component of geomagnetic data observed by some seismostations in recent 30 years, such as Hongshan, Houtuqiao, are analyzed, and the annual rate of Z component is also studied.The results show:ended the yearly ascending tendency, the long term variation of F and Z component showed a turning re-spectively in 1999 and 2000, but recovered a little in some local region in recent two years;with a descending tendency, the H component did not change.The slow down of variations in Z component is usually relevant to the relatively strong earthquake in North China area.