Seismic noise study in the underground Baksan Neutrino Observatory

Abstract

In this paper we report a study of the seismic noise measured in the underground Baksan Neutrino Observatory. The main spectral feature below 1 $Hz$ is the oceanic microseism, while for greater frequencies the measured horizontal and vertical accelerations approaches the Peterson low noise model. Using two synchronized seismometers we also studied the coherence in the microseismic band ($0.1-0.5Hz$) between three underground stations located at $0.3km$, $1.4km$ and $3.7km$ from the tunnel entrance. Finally, on the base of our measurements we evaluate the Newtonian noise limit at this site using the Saulson's model.