Source Distribution Analysis of Seismic Ambient Noise in Western Junggar

摘要

The ambient noise source distribution in Western Junggar,Xinjiang province of China,has been studied in this article.We used one-month seismic data that collected by an array deployed there.After a series of preprocessing,long-time records were cut into short sections to meet the single noise source requirement.Through quantitatively calculating array response function at several frequencies,a best window (0.5-3 Hz) for frequency-domain beamforming (f-k analysis)was determined.A criterion for sorting data was proposed to enhance the accuracy as well.We chose sliding-window f-k analysis to depict high quality distribution of the dominant noise source.The result indicates that there is a persistent and stable noise source at 1-2.5 Hz in Western Junggar.It comes from 60 degrees east of north (NEE) at an apparent velocity of 2700 m/s,which is produced mainly by varies kinds of human activities in and near Karamay city.Besides,a source with relatively stronger and faster noise occurs in the orientation of 80 degrees west of north(NWW) sometimes.