Observation of co-seismic electromagnetic waves associated with the Geiyo earthquake in 2001
Observation of co-seismic electromagnetic waves associated with the Geiyo earthquake in 2001
复制标题
2001年艺予地震同震电磁波观测
DOI：
10.1109/aps.2002.1016987
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
M. Nishi
中科院分区：
文献类型：
--
作者：
T. Yoshida;K. Yabu;M. Nishi
为了阐明电磁现象和地震活动之间的关系，已经进行了许多观测。在我们的观测系统中，与eq相关的电磁波是在甚高频（VHF）波段接收到的。我们开发了一种利用高灵敏度调频调谐器的双频观测方法。我们的观测方法可以澄清和判断接收到的信号是宽带电磁波还是调频广播波。2001年发生了Geiyo EQ （M/sub J/=6.4, d=60 km）和Geiyo EQ （M/sub J/=5.2, d=50 km）的余震。我们的观测系统在甚高频波段探测到与Geiyo EQ相关的同震宽带电磁波。观察到的电磁波在EQ后达到峰值，并在大约3小时后缓慢恢复到正常水平。我们还描述了一个新的现象：在Geiyo EQ前一天左右出现了一个约2db的小波动，然后，这个波动在地震发生时刚好消失。
Many observations have been conducted to clarify the relationship between electromagnetic (EM) phenomena and earthquake (EQ) activities. In our observation system, EM waves associated with EQs have been received in the very high frequency (VHF) band. We have newly developed a dual frequency observation method with a highly sensitive synthesized FM tuner. Our observation method can clarify and judge whether a received signal is a broadband EM wave or an FM broadcasting wave. We had the Geiyo EQ (M/sub J/=6.4, d=60 km) and the aftershock of the Geiyo EQ (M/sub J/=5.2, d=50 km) in 2001. Our observation system detected co-seismic broadband EM waves associated with the Geiyo EQ in the VHF band. The observed EM waves reached a peak right after the EQ and slowly returned to a normal level about three hours later. We also describe a new phenomenon: a small fluctuation of about 2 dB occurred about one day before the Geiyo EQ, then, the fluctuation just disappeared at the occurrence of the earthquake.