In order to evaluate the background noise level of PET/gPhone gravimeter of the National Gravity Network, we collected and processed 4a continuous gravity data recorded by the 52 PET/gPhone gravimeters from 2014 to 2017.
(1) DaySNM method can find the lowest SNM, compared with the Banka and Bandpass method.
(2) the variation range of SNM (Seismic Noise Level) in mainland China is 2.013 (Yutian) ~ 4.654 (Yinchuan), and the variation range of SSNM (SubSeismic Noise Level) is 5.024 (Gelmud) ~ 6.500 (Liyang).
(3) SNM in coastal areas generally larger than inland gravimeters. Conclusions: Our study suggested that wave pulsation may be the main reason for the loud noise of coastal stations; eastern and northern Qinghai-Tibet Plateau, which may be related to frequent geological tectonic activities in these areas;