Abstract

We estimated the level of seismic noise for stations of the KyrgyzNetwork (KNET) for 19 years of its operation (1999–2017) in real time. For each channel of a seismic station (east–west, north–south, vertical) we selected fifteen-minute segments of 100-Hz seismic noise distributed over all seasons of the year (March, June, September, and December) and several times of the day (0, 6, 12, and 18 h UTC). We calculated power spectral densities of seismic noise and found the probability density of signal power spectral density for all selected frequencies/periods. The resulting distributions were compared with Peterson’s seismic noise models (Peterson, 1993). The maximum absence of stochastic noise occurred at 00 and 18 h UTC for all KNET stations. The level of seismic noise is little affected by the seasons at periods of 2–5 s, slightly lowering in the summer and increasing in the cold seasons at periods of 5–10 s. September is the less favorable for periods of 0.02–2 s. The stations as a whole possess good characteristics at periods of 0.02–10 s (frequencies of 0.1–50 Hz) and can well be said to be noiseless.

中文翻译：

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KNET站的地震噪声水平研究

摘要

我们实时估算了吉尔吉斯网络（KNET）运营19年（1999–2017）的地震噪声水平。对于地震台站的每个通道（东西，北，南，垂直），我们选择了15分钟的100 Hz地震噪声，这些噪声分布在一年中的所有季节（3月，6月，9月和12月）中，几次当天（UTC时间0、6、12和18小时）。我们计算了地震噪声的功率谱密度，并找到了所有选定频率/周期的信号功率谱密度的概率密度。将所得的分布与彼得森的地震噪声模型进行了比较（Peterson，1993）。对于所有KNET站，随机噪声的最大缺失发生在UTC的00和18 h。2-5 s的季节中，地震噪声的水平几乎不受影响，夏季略有降低，在寒冷季节5-10 s时有所增加。在0.02–2 s期间，9月较差。整个电台在0.02–10 s（0.1–50 Hz的频率）周期内具有良好的特性，并且可以说是无噪音的。