Characterizing urban seismic noise recorded by distributed acoustic sensing array

Ambient noise interferometry is based on the assumption of normally distributed noise sources, which is often hard to be satisfied in urban areas where local noise sources may be dominant in specific directions and times. Hence, understanding the characteristics of urban seismic noises is important to extract reliable surface waves for urban monitoring. In this study, we characterize urban seismic noise sources using a distributed acoustic sensing (DAS) fiber-optic array deployed in the city of State College, PA. We analyze spatial variation of background noise between off-campus areas and the main campus. We particularly show discovered wind-induced signals at resonant frequencies of 0.6 and 1.2 Hz and rain-induced signals at broadband frequencies (1 - 110 Hz). We also discover the distinct DAS recordings of three road-fiber geometries. The characteristics of different noise sources we reported will be expected to provide clues when conducting ambient noise interferometry of these DAS recordings.