Impact of seasonal variations of ambient seismic noise level on the number of registered earthquakes in the Arctic regions

Abstract

Researchers at the Seismological Laboratory of the Institute of Geodynamics and Geology of the Federal Center for Integrated Arctic Research of the Russian Academy of Sciences (FCIARctic) have been engaged in the seismological monitoring of the European Arctic sector since 2011. In this paper, we present a comparative assessment of the earthquakes spatial distribution in this region based on the data from the International Seismological Centre (ISC) and the FCIARctic’s Arkhangelsk Seismic Network (ASN) obtained in 2012–2016. The paper presents the waveforms of earthquakes occurred at the Gakkel Ridge and the Svalbard archipelago processed with the use of a Russian software package WSG (Windows Seismic Grafer) recommended by the Unified Geophysical Service of the Russian Academy of Sciences. A standard 4–8 Hz bandpass filter was used for the processing of regional Arctic earthquakes. The impact of seasonal variations on the quality of earthquakes registration was analysed based on the seismograms recorded by the ASN’s island-based Arctic stations from 2012 to 2014 The same analysis was done for the central broadband sensor SPA0 of the Norwegian NORSAR-owned SPITS group installed at the Svalbard archipelago. A correlation has been established between the number of earthquakes recorded by the ASN’s island Arctic stations and SPA0 station. The number of regional earthquakes, recorded by ASN’s island Arctic stations is is smaller in summer-autumn periods than in winter periods. Forthe SPA0 station, which is part of SPITS group, there is not seasonality in the number of registered earthquakes. Generally, earthquakes are recorded uniformly, exception on January. This might be due to the increased seismic activity in the Svalbard archipelago during that period.