摘要
采用成都台和天水台GM4磁通门磁力仪秒采样地磁数据,计算得到这2个台站的20~230 s周期的谐波振幅比,发现该周期范围内的谐波振幅比在地震前出现的异常与10~60 min周期的谐波振幅比类似,主要表现为下降—转折—恢复上升的变化形态。成都台的谐波振幅比异常呈现南北方向和长短周期均不同步的特征,而天水台只有长短周期之间出现不同步现象。根据异常特征推测天水台位于岷县—漳县6.6级地震前的高导体区域内,而成都台则位于芦山7.0级地震前的高导体东侧边界附近。
This paper calculates the geomagnetic harmonic wave amplitude ratio with periods of 20 - 230 s by using the data of GM4 fluxgate magnetometer at the Chengdu station and Tianshui station. We find that the abnormal varia- tions of geomagnetic harmonic wave amplitude ratio with periods of 20 - 230 s showed the characteristics of down-turning-recovery before earthquakes, which were same as the abnormal variations of geomagnetic harmon- ic wave amplitude ratio with periods of 10 - 60 min. At the Chengdu station, there was asynchronization between north-south direction and west-east direction, and also between long-period and short-period. However, the a- synchronous phenomenon at the Tianshui station only existed between long-period and short-period. According to the anomaly characteristics, we infer that the Tianshui station was located in the high conductive body before the Minxian-Zhangxian M6.6 earthquake, and the Chengdu station located near the east border of the high conduc- tive body before the Lushan M7.0 earthquake.
作者
倪晓寅
陈莹
NI Xiaoyin CHEN Ying(Fujian Earthquake Agency, Fuzhou 350003, Fujian, Chin)
出处
《地震研究》
CSCD
北大核心
2017年第3期431-436,共6页
Journal of Seismological Research
基金
2015年度中国地震局青年震情跟踪课题<基于秒数据的地磁转换函数强震前变化特征研究>(2015010407)资助
关键词
地磁场
谐波振幅比
岷县-漳县6.6级
芦山7.0级地震
geomagnetic field
harmonic wave amplitude ratio
the Minxian-Zhangxian M6.6 earthquake
the Lushan M7.0 earthquake
