Judging the Quality of Alternative Station Foundation by the Change of Power Spectrum Curve of Background Noise
CHEN Yang
SHI Tianhong
ZHU Tao
WANG Enkang
WANG Xijun
LI Bo
LIU Fei
Abstract：Taking the sites of three seismic stations in Jinping,Malipo,and Hekou,Yunnan Province as exam-ples,this paper explained the quality of the station foundation revealed by the degree of dispersion of the power spectrum curves by comparing the differences in the 24-hour background noise power spectrum curves of the sites of the preliminary survey and re-survey stations.The station sites with a high degree of dispersion of the power spec-trum curves were susceptible to the influence of interference,whereas those with a convergent and low degree of dispersion of the power spectrum curves had a superior quality and were not susceptible to the influence of near-field interference.This result suggests that the degree of dispersion of power spectrum curves is indicative of the im-munity of the station sites to near-field interference.Further investigation indicates that the low-frequency disper-sion of the power spectrum curve of short-period seismometer recording data mainly originates from the equivalent tilt signals recorded outside the passband.Conversely,the interfering signals in the high-frequency band predomi-nantly emanate from the near-field vibrational interferences.The key to reducing the aforementioned interference lies in setting up the instrument on bedrock rather than on rolling stones.This hypothesis has been substantiated by the subsequent re-survey.
Keywords：Seismic station site selectionNoise power spectral densityStation fundation quality judgmentNoiseInterference
Publication Date：2025-09-30
Online Publishing Date：2025-10-10(First online date of this platform, not the publication date of the document)
Pages：7( 35-41 )