摘要
本文讨论了青海祁连俄博测点和甘肃山丹霍城测点1979年7月—1986年10月间的大地电磁测深重复观测试验结果。测点所在地区的电磁干扰背景较小、地震活动性较强。文中分析了观测记录和资料处理中的误差。结果表明,以初始值为基准,俄博测点1984年两次复测的视电阻率曲线在部分频带范围内出现过15—30％左右的系统变化,与此期间测区附近发生的一些M≈5的地震活动有着一定的对应关系;1985年复测的视电阻率曲线又恢复至初始值,而此期间测区附近没有M≈5及其以上的地震活动,1986年霍城测点和俄博测点复测的视电阻率曲线在较宽的频带范围内发生了40—70％左右的系统变化,与此期间震中距为60km左右的青海门源M=6.7,5.7和5.0地震群密切相关。
This paper deals with test results of repeated observations of the apparent resistivity at the Ebo site,Qilian,Qinghai Province and at Huocheng,Shandan,Gansu Province from July 1979 to October 1986 by the MT method. The noise background is low and seismicity is high around the observation sites. The errors of observations are analysed and discussed. It is found that in comparison with initial curves,systematic changes of 15-30% in the apparent resistivity in part of the frequency range of two repeated observations in 1984 at the Ebo site were associated with the occurrences of earthquakes of M≈5 around the sites; then returning to initial values when measurements were repeated in 1985 at the Ebo site with no earthquakes of M≈5 occurring around the sites. Systematic changes of 40-70% in the apparent resistivity in the entire frequency range repeatedly observed in 1986 at the Ebo site and at the Huocheng site were closely associated with the occurrences of earthquakes of M=6.7,5.7,5.0 at Menyuan,Qinghai Province. The epicentral distances of the two observation sites were about 60 km.
出处
《地震学报》
CSCD
北大核心
1989年第1期98-105,共8页
Acta Seismologica Sinica
