The mechanism of loro frequency noise and the measures to getting the good records

低频大地噪声的产生机理及获得良好记录的措施我们猜测低频大地噪声与气压梯度或风力有关，因此我们用宽频带地震仪（STS-1）观测低频大地噪声，用高灵敏度气压计观测大气压的变化。为了得到大气压力梯度，我们在名古屋市和濑户市观测了大气压力的变化。通过对这些资料的分析，发现低频大地噪声的波形不像观测站周围气压梯度的变化，而像是鹿山站气压的变化，并发现钻孔式宽频带地震计中的大低频噪声，但这些波形不像大气压的波形，我们得出结论，低频噪声是一种仪器噪声。

T mechanism of low frequency earth noise and the measures to getting the good recordsWe have guessed the low frequency earth noise associated with the gradientof atmospheric pressure or the force of wind, so that we observed the low frequency earth noise using a broad-band seismometer (STS-1) and observed the change of atmospheric pressure using a high sensitive barometer at lnuyama seismic station. In order to get the gradient of atmospheric pressure, we observed the change of atmospheric pressure at Nagoya city and Seto city. We analized these data and fined that the wave form of low frequency earth noise does not look like the change of atmospheric pressure gradient around the observation station, but look like the change of atmospheric pressure at lnuyama station.In addition, we fined that the big low frequency noise in the bore-hole type broad-band seismometer, however these wave form dose not look like atmospheric pressure.We came to the conclusion that the low frequency noise are a kind of the instrumental noise.