Long term seismic noise acquisition and analysis in the Homestake mine with tunable monolithic sensors

In this paper we describe the scientific data recorded along one month of data taking of two mechanical monolithic horizontal sensor prototypes located in a blind-ended (side) tunnel 2000 ft deep in the Homestake (South Dakota, USA) mine chosen to host the Deep Underground Science and Engineering Laboratory (DUSEL). The two mechanical monolithic sensors, developed at the University of Salerno, are placed, in thermally insulating enclosures, onto concrete slabs connected to the bedrock, and behind a sound-proofing wall. The main goal of this experiment is to characterize the Homestake site in the frequency band 10 -4 ÷ 30 H z and to estimate the level of Newtonian noise, providing also the necessary preliminary information to understand the feasibility of underground gravitational-wave interferometers sensitive at 1 H z and below.