ANOMALOUS REDUCTION IN THE LEVEL OF SEISMIC NOISE IN PETROPAVLOVSK-KAMCHATSKY IN APRIL 2020

Estimation of the influence of anthropogenic factors on the seismic signal is an important problem in ensuring the quality of seismological data and, accordingly, the quality of scientific research. Due to the unprecedented situation associated with the introduction of measures to prevent the spread of COVID-19, non-working days were established in Russia from April 4 to April 30, 2020. It became possible to assess the impact of a notable decrease in anthropogenic activity on the seismic signal (noise) recorded by seismic instruments in the territory of the largest city of the Kamchatka, Petropavlovsk-Kamchatsky. We study seismic noise by standard technique, based on the analysis of the probability density function of the noise power spectral density obtained from the data of the digital archive of the noise spectra of seismic stations. A decrease in the seismic noise power level below the minimum values of the same periods of previous years was registered at stations installed in schools, residential buildings (boarding schools) or near public and office buildings. The minimal anthropogenic influence stations were selected. The obtained data can be used for determination the features of the work of both stations and individual channels, taking into account their direction and position, relative to the objects of human activity.