Low frequency seismic noise acquisition and analysis with tunable monolithic horizontal sensors Fausto Acernese a,b , Rosario De Rosa b,c , Riccardo De Salvo d , Gerardo Giordano a , Jan Harms e , Vuk Mandic e , Rocco Romano a,b , Thomas Trancynger f , Silvia Vilasi a,b , Fabrizio Barone a,b a Universit` a degli Studi di Salerno, Fisciano (SA), Italia b INFN sez. di Napoli, Napoli, Italia c Universit` a di Napoli “Federico II”, Napoli, Italia d California Institute of Technology, Pasadena, CA, U.S.A. e University of Minnesota, Twin Cities, MN, U.S.A. f South Dakota Science and Technology Authority, Lead, SD, U.S.A. ABSTRACT In this paper we present and discuss 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 mine (South Dakota, USA), chosen to host the Deep Underground Science and Engineering Laboratory (DUSEL). The main goal of this test is to provide preliminary data to characterize the Homestake site in the frequency band 10 -4 ÷ 30 Hz and to estimate the level of Newtonian noise, information necessary to understand the feasibility of underground gravitational-wave interferometers sensitive at 1 Hz and below. The recorded scientific data and all the technical information obtained with this test are very useful also to understand the performances of the monolithic sensors in the very low frequency band (10 -6 ÷ 10 -3 Hz) and to organize an experiment for the low frequency seismic characterization of the Homestake site with monolithic sensors positioned at different levels and orientations. Keywords: Monolithic Sensor, Folded Pendulum, Seismometer, Seismic Noise 1. INTRODUCTION The Homestake mine is the largest known iron-formation-hosted gold-ore body, marked by a rather complicated stratification and history of folding events and metamorphosis of igneous and sedimentary rocks. It lies far from the oceans in the Lead-Deadwood Dome of the Black Hills (South Dakota, USA) and has the deepest reaching tunnels in North America (8000 ft) which provides an optimal stage for monitoring the seismic noise with a three dimensional network of seismometers. In figure1 a picture of one of the admittances to the mine is shown. Recently, the Homestake mine was chosen to host the Deep Underground Science and Engineering Laboratory (DUSEL). For this task, in August 2008 a first series of seismic measurements were performed at different underground levels in the Homestake mine, the 300 ft, the 800 ft and 2000 ft levels, intended as a starting point for a more exhaustive survey. 1 In December 2008, the group of Applied Physics of the University of Salerno installed at Homestake two prototypes of monolithic seismometers in thermally insulating enclosures onto concrete slabs connected to the bedrock and behind a sound-proofing wall. The main goal of this test is to provide preliminary data necessary to characterize the Homestake site in the frequency band 10 -4 ÷ 30 Hz and to estimate the level of Newtonian noise, information necessary to understand the feasibility of underground gravitational-wave interferometers sensitive at 1 Hz and below. The recorded scientific data and all the technical information obtained with this test will also be used both to understand the performances of the monolithic sensors in the very low frequency band (10 -6 ÷ 10 -3 Hz) and to organize an experiment for the low frequency seismic characterization of the Homestake site with monolithic sensors positioned at different levels. Send correspondence to Fabrizio Barone - e-mail: fabrizio.barone@na.infn.it Earth Resources and Environmental Remote Sensing/GIS Applications, edited by Ulrich Michel, Daniel L. Civco, Proc. of SPIE Vol. 7831, 78311D · © 2010 SPIE · CCC code: 0277-786X/10/$18 · doi: 10.1117/12.865069 Proc. of SPIE Vol. 7831 78311D-1 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 10/28/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx