The observation of broadband co-seismic electromagnetic waves in VHF band
The observation of broadband co-seismic electromagnetic waves in VHF band
复制标题
VHF波段宽带同震电磁波观测
DOI：
10.1109/aps.2001.958823
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
M. Nishi
中科院分区：
文献类型：
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作者：
T. Yoshida;M. Nishi
电磁场观测一直被认为是地震短期预报最有希望的候选者之一。我们一直对甚高频波段感兴趣，因为与其他较低的频段相比，甚高频波段很少有人工和城市噪音源。我们的观察方法，合成调谐器的方法，与PLL型调频调谐器，具有高的频率稳定性和灵敏度从76 MHz到90 MHz。在本文中，我们描述了观测系统的配置和一个新提出的双频观测方法，以实现更精确的观测的基础上的综合调谐器的方法。我们的观测方法可以检测到约-120 dBm（0.001 pW）的接收电平。因此，它可以观察到约-114 dBm的银河噪声。此外，本文表明，我们的系统在广岛城市大学成功地观察到自然辐射的VHF波对应于鸟取县西武地震（7.1级，深度10公里）在2000年10月6日。
Observations in electromagnetic fields have been considered as one of the most promising candidates for short-term earthquake prediction. We have been interested in VHF band where there are few artificial and urban sources of noise compared with other lower frequency bands. Our observation method, the synthesized tuner method, with a PLL type FM tuner which has a high frequency stability and sensitivity from 76 MHz to 90 MHz. In this paper, we describe the observation system configuration and a newly proposed the dual frequency observation method in order to realize more accurate observations based on the synthesized tuner method. Our observation method can detect up to about -120 dBm (0.001 pW) of the received level. Therefore it can observe galactic noise of about -114 dBm. Moreover, this paper shows that our system in Hiroshima City University successfully observed the naturally radiated VHF wave corresponding to the Tottori-ken Seibu Earthquake (magnitude 7.1, depth 10 km) on October 6 in 2000.