新冠疫情防控前后湖北恩施地震台背景噪声变化分析

Analysis of seismic ambient noise before and after the prevention andcontrol of COVID\|19 pandemic at Enshi station, Hubei Province

摘要:

利用2018年1月至2020年3月恩施地震台站观测的垂直分量连续波形数据,通过计算噪声功率谱密度和概率密度函数,统计其不同频段功率谱密度分布情况,对比分析疫情前后恩施地区噪声水平变化特征。同时,将2018年、2019年和2020年垂直向地震噪声的加速度幅值进行对比,发现春节前几日的加速度幅值变化曲线高度一致,表明这三年间恩施地震台周边高频噪声源和地震仪运行情况非常稳定。研究发现,恩施地区在新冠疫情防控期间,由人类活动引起的地震高频噪声迅速降低,显示出较强的政策执行力度;恩施地区高频段(~10 Hz)噪声水平下降了1~20 dB;日间幅值显著下降,夜间噪声低值略有降低。因此基于地震背景噪声的测算和分析可为人类活动监测和城市公共管理提供有力手段。

Abstract:

Based on the continuous waveform data recorded by Enshi seismic station in Hubei Province from January 2018 to March 2020, we obtained the distribution of PSD in different frequency bands by calculating the power spectral density (PSD) and probability density function (PDF), and then compared and analyzed the variation characteristics of seismic ambient noise before and after the COVID-19 pandemic. Meanwhile, we compared the vertical acceleration amplitudes of seismic noise in 2018, 2019, and 2020, and found that the acceleration amplitude variation curves were highly consistent in the days before the Spring Festival, indicating that the operation of high-frequency noise sources and seismometers around Enshi seismic station were very stable in these three years. The results showed that during the prevention and control period of COVID-19 in Enshi area, the high-frequency noise caused by human activities rapidly decreased, and the noise in the high frequency band (~10 Hz) decreased by 1-20 dB. The amplitude decreased significantly during the day and the low value of noise decreased slightly at night. The calculation and analysis of seismic ambient noise can provide a powerful means for human activity monitoring and urban public management.