Analysis of the Background Noise in the Seismic Frequency Band of the Global Superconducting Gravimeter

Detailed research was conducted on the assessment methods for the background noise levels at superconducting gravimeter stations. Based on this method, multiple superconducting gravity observation data before and after the 2010 Chile earthquake, the 2011 Tohoku earthquake and the 2015 Chile earthquake were selected to evaluate the background noise levels in the seismic frequency band, and the background noise level SNM for different stations was obtained. A statistical analysis of the 5 days with the lowest background noise levels recorded by different superconducting gravimeters was performed, and the continuous superconducting gravity data of multiple stations including major earthquake events were used to obtain the quietest period, the period from 5 days before the occurrence of large earthquake to 10 days after the occurrence of a major earthquake can be disregarded, which provides a reference for the selection of the seismic quiet period segment for multiple stations.