August 1, 2014.
The Laser Interferometer Gravitational Wave Observatory (LIGO) was developed to exploit Einstein's prediction of gravitational waves to develop a new way to study the universe. Gravitational waves are detected by observing changes less than 1/10000 of the diameter of a proton in the distances between hanging mirrors that are four kilometers apart within two perpendicular evacuated tubes. These changes in distances between mirrors are produced by gravitational waves from large masses in space, such as colliding black holes. Many factors affect the sensitivity of the interferometer. LIGO’s Physical Environment Monitoring subsystem (PEM) is one method of both eliminating noise and assisting in identifying false indications of gravitational wave detection. The objectives of this study were to investigate the statistics of wind at LIGO Hanford’s three building locations, develop understanding of the statistics of ground motion in relationship to the interferometer performance, and study the correlation between wind and ground motion. Excel was used to analyze eight years of data (2004-2012) and to represent the wind patterns and seismic motion throughout each year and across the series. Preliminary results suggest The wind speed exceeded 10 m/s at least briefly in 15% of the hours in the eight years analyzed. Ground motion appears to significantly increase above this threshold. Also shown was during each of the spring months, the wind was greater than 10 m/s in more than 15% of the hours, peaking at 24% in April. Recommendations include developing systems to adapt to winds over 10 m/s.
Science and Mathematics Education
Pacific Northwest National Laboratory (PNNL)
This material is based upon work supported by the S.D. Bechtel, Jr. Foundation and by the National Science Foundation under Grant No. 0952013. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the S.D. Bechtel, Jr. Foundation or the National Science Foundation. This project has also been made possible with support of the National Marine Sanctuary Foundation. The STAR program is administered by the Cal Poly Center for Excellence in Science and Mathematics Education (CESaME) on behalf of the California State University (CSU).