Temporal changes in anthropogenic seismic noise levels associated with economic and leisure activities during the COVID-19 pandemic
Hiro Nimiya, Tatsunori Ikeda, Takeshi Tsuji
Received date: 9th September 2020
Seismic noise of frequencies >1 Hz includes noise that is strongly related to human activities. Reduction in seismic noise during the COVID-19 pandemic has been observed worldwide as restrictions were imposed on numerous human activities to control outbreaks of the virus. In this context, we studied the effect of reduced anthropogenic activities during COVID-19 on the noise levels in the Tokyo metropolitan area, Japan, considering seasonal variation. A significant reduction in noise was observed during the emergency, including that of frequencies >20 Hz, which was associated with school activities. After lifting the state of emergency, noise reverted to previous levels immediately for weekdays, but gradually for Sunday. This was likely because economic activities instantly resumed post-emergency on weekdays; however, most people still continued to avoid non-essential outings on Sunday. We also observed seasonal variation related to school holidays, energy consumption, and industrial activity. Noise levels in the frequency range of 1–5 Hz were found to be related to construction activity, which increased in winter and gradually decreased from 2017. Our findings demonstrate that seismic noise can be used to monitor economic activities and movement of people at a local scale.
This is an abstract of a preprint hosted on a preprint server, which is currently undergoing peer review at Scientific Reports. The findings have yet to be thoroughly evaluated, nor has a decision on ultimate publication been made. Therefore, the results reported should not be considered conclusive, and these findings should not be used to inform clinical practice, or public health policy, or be promoted as verified information.