Quantifying seismic noise caused by coal diggers

Thesis details

Quantifying seismic noise caused by coal diggers

• 6 months
• M.Sc.
• 90% Programming
• 80% Field work
• 10% Lab work
• 60% Theory
• 70% Processing
• 60% Interpretation
• 50% Geology

Contact person

©

Dr. rer. nat.

Marc S. Boxberg

Postdoctoral researcher and deputy director

marc.boxberg@gim.rwth-aachen.de

+49 241 / 80 99755

The underground Einstein Telescope is a planned observatory for gravitational waves. Gravitational waves are, for example, excited when stars collide. When this happens vibrations are triggered in the space-time. When a gravitational wave passes, there is tiny deformation happening in matter and extremely sensitive instruments are needed to register these deformations. For this purpose three 10-kilometer tunnels shall be build about 250 to 300 meters underground. The length of these tunnels will be constantly monitored with sensitive lasers to detect tiny but specific patterns in the variations of the length. However, seismic waves can also cause deformation and, therefore, seismic events as well as seismic noise has to be monitored to a very high precision.

One potential source of noise is associated with mining activities. In Germany, lignite (or brown coal) is mined in about 25 to 40 km distance to the planned location of the Einstein telescope. The diggers create constant noise while mining coal and removing the overburden. It is necessary to quantify the noise caused by the diggers and evaluate whether this noise source in such a distance needs to be considered in the processing of data from the Einstein telescope as well as in the planning of the correct location and orientation of the telescope.

In 2021 and 2022 a temporary seismic network was deployed in the area of Weisweiler. Stations were located close to and even within the open-pit lignite mine Inden. This seismic network allows to assess the noise associated with coal diggers.

Your tasks:

• Beamforming methods could be used to determine the origin of the noise and to correlate it with it’s actual source.
• Probabilistic power spectral density (PSD) curves calculated for different time windows and stations with different distances to the mine could be used to quantify the noise and the noise reduction with distance to the mine.

Supplementary Documents

Finger, C., Roth, M. P., Dietl, M., Gotowik, A., Engels, N., Harrington, R. M., Knapmeyer-Endrun, B., Reicherter, K., Oswald, T., Reinsch, T., and Saenger, E. H. (2023). The Weisweiler passive seismological network: optimised for state-of-the-art location and imaging methods. Earth Syst. Sci. Data, 15:2655–2666, doi: 10.5194/essd-15-2655-2023.

Behr Y., Townend J., Bowen M., Carter L., Gorman R., Brooks L., Bannister S. (2013). Source directionality of ambient seismic noise inferred from three-component beamforming. J. Geophys. Res., 118(1):240–248, doi: 10.1029/2012JB009382.