Abstract. A noticeable decrease in seismic noise was registered worldwide during the lockdown measurements of 2020 to prevent the Covid-19. In Central America, strong lockdown measures started during March of 2020. We have used seismic stations from Costa Rica, Guatemala, El Salvador, and Nicaragua to study the effects of these measures on seismic records by characterizing temporal variations in the high-frequency band (4–14 Hz) via spectral and amplitude analyses. In addition, we study the link between the reduction of seismic noise and the number of earthquake detection and felt reports in Costa Rica and Guatemala. We found that seismic stations near the capitals of Costa Rica, Guatemala, and El Salvador, presented a decrease in the typical seismic noise level from 200 to 140 nm, 100 to 80 nm, and 120 to 80 nm, respectively. Our results showed that the largest reduction of ~50 % in seismic noise were observed in seismic stations near main airports, busy roads, and densely populated cities. In Nicaragua, the seismic noise levels remained constant (~40 nm) as no lockdown measures were applied. We noted that the decrease in seismic noise levels allowed to improve earthquake locations and increment the number of reports of low magnitude felt earthquakes. Our results imply that seismic data can be useful to verify the compliance of lockdown measures and to explore effects of the decrease in the seismic noise in the earthquake detection and felt reports.

中文翻译：

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Covid-19 锁定对中美洲地震记录的影响

摘要。在 2020 年为防止 Covid-19 的封锁测量期间，全球范围内的地震噪声显着下降。在中美洲，强有力的封锁措施于 2020 年 3 月开始。我们使用来自哥斯达黎加、危地马拉、萨尔瓦多和尼加拉瓜的地震台站，通过表征高频段的时间变化来研究这些措施对地震记录的影响（ 4–14 Hz）通过频谱和幅度分析。此外，我们研究了哥斯达黎加和危地马拉地震噪声的减少与地震探测和有感报告数量之间的联系。我们发现哥斯达黎加、危地马拉和萨尔瓦多首都附近的地震台站的典型地震噪声水平分别从 200 到 140 nm、100 到 80 nm 和 120 到 80 nm 降低。我们的结果表明，在主要机场、繁忙的道路和人口稠密的城市附近的地震台站中，观察到的地震噪声最大减少了约 50%。在尼加拉瓜，由于没有采取封锁措施，地震噪声水平保持不变（约 40 海里）。我们注意到地震噪声水平的降低可以改善地震位置并增加低震级有感地震的报告数量。我们的结果意味着地震数据可用于验证锁定措施的合规性以及探索地震检测和有感报告中地震噪声降低的影响。由于没有采取锁定措施，地震噪声水平保持不变（~40 nm）。我们注意到地震噪声水平的降低可以改善地震位置并增加低震级有感地震的报告数量。我们的结果意味着地震数据可用于验证锁定措施的合规性以及探索地震检测和有感报告中地震噪声降低的影响。由于没有采取锁定措施，地震噪声水平保持不变（~40 nm）。我们注意到地震噪声水平的降低可以改善地震位置并增加低震级有感地震的报告数量。我们的结果意味着地震数据可用于验证锁定措施的合规性以及探索地震检测和有感报告中地震噪声降低的影响。