Locating wind farms by seismic interferometry and migration
- 185 Downloads
We present a case study on the detection and quantification of seismic signals induced by operating wind turbines (WTs). We spatially locate the sources of such signals in data which were recorded at 11 seismic stations in 2011 and 2012 during the TIMO project (Deep Structure of the Central Upper Rhine Graben). During this time period, four wind farms with altogether 12 WTs were in operation near the town of Landau, Southwest Germany. We locate WTs as sources of continuous seismic signals by application of seismic interferometry and migration of the energy found in cross-correlograms. A clear increase of emitted seismic energy with rotor speed confirms that the observed signal is induced by WTs. We can clearly distinguish wind farms consisting of different types of WTs (different hub height and rotor diameter) corresponding to different stable frequency bands (1.3–1.6 Hz, 1.75–1.95 Hz and 2.0–2.2 Hz) which do not depend on wind speed. The peak frequency apparently is controlled by the elastic eigenmodes of the structure rather than the passing of blades at the tower. From this we conclude that vibrations are coupled into the ground at the foundation and propagate as Rayleigh waves (and not as infrasound). The migration velocity of 320 m/s corresponds to their group velocity. The applied migration method can contribute to the assessment of local sources of seismic noise. This topic gets growing attention in the seismological community. In particular, the recent boost of newly installed wind farms is a threat to seismological observatories such as the Black Forest Observatory (BFO) and the Gräfenberg array (GRF) or gravitational wave observatories (e.g. LIGO, VIRGO) in terms of a sensitivity degradation of such observatories.
KeywordsSeismology Seismic noise Wind turbines Migration Seismic interferometry Cross-correlation
Seismic data were provided by the “Erdbebendienst Südwest”, the “Federal Institute for Geosciences and Natural Resources (BGR)” and the “Karlsruher Broadband Array (KABBA)”. We thank pfalzwind GmbH (Ludwigshafen/Germany) for the provision of data and their support of this work. We would like to thank the two anonymous reviewers and the editor for their helpful and constructive suggestions and comments.
T.Z. was financed by the project “TremAc”, which is funded by the Federal Republic of Germany. Awarding authority: The Federal Ministry for Economic Affairs and Energy based on a resolution of the German Bundestag.
- Groos J (2010) Broadband seismic noise: classification and green’s function estimation. Dissertation at the Karlsruhe Institute of Technology, KITopen ID: 1000021099. https://publikationen.bibliothek.kit.edu/1000021099
- Mündel R (2009) Überwachung zeitlicher Änderungen in der Ausbreitung elastischer Wellen als Folge von CO2-Einlagerungen im Untergrund. Diplomarbeit, Institut für Geophysik und Geologie, Universität LeipzigGoogle Scholar
- Ritter JRR (2011) Konzeptionelle Ansätze zur Überwachung induzierter Seismizität im Oberrheingraben in Rheinland-Pfalz. Mainzer geowiss Mitt 39:157–176Google Scholar
- Schofield R (2001) Seismic measurements at the stateline wind project. Rept No LIGO T020104-00-Z, Laser Interferometer Gravitational-Wave Observatory, available at http://www.ligocaltechedu/docs/T/T01010400pdf
- Spies T, Schlittenhardt J, Schmidt B (2017) Abschlussbericht für das Verbundprojekt MAGS2: Mikroseismische Aktivität geothermischer Systeme 2 (MAGS2) - vom Einzelsystem zur großräumigen Nutzung : Einzelprojekt EP4: Ermittlung der seismischen gefährdung bei tiefer geothermischer Energiegewinnung unter Berücksichtigung der regionalen und lokalen geologisch-tektonischen Strukturen. https://zsn.bgr.de
- Stein F (2013) Determination of seismic waveforms using passive seismic interferometry around Landau, SW Germany. Diploma Thesis at the Karlsruhe Institute of Technology, KITopen ID: 1000037676 https://publikationen.bibliothek.kit.edu/1000037676
- Styles P, England R, Stimpson IG, Toon SM, Bowers D, Hayes M (2005) Microseismic and infrasound monitoring of low frequency noise and vibrations from windfarms: recommendations on the siting of windfarms in the vicinity of Eskdalemuir, Scotland. Keele University, UK. https://www.keele.ac.uk/geophysics/appliedseismology/wind/Final_Report.pdf Google Scholar
- Xi Engineering Consultants Ltd (2014) Seismic vibration produced by wind turbines in the Eskdalemuir region. https://www.gov.scot/Topics/Business-Industry/Energy/Infrastructure/Energy-Consents/Guidance/reportseismicvibrations