Emmy-Noether-Project "Bridging Geodesy and Seismology"

Characterization of small local noise sources with array seismology

Ritter, J. R. R. and H. Sudhaus (2007)

Near Surface Geophysics 5(4): 253-261.

DOI: 10.3997/1873-0604.2007007

earthdoc.org
 

Abstract:

Seismic noise is often regarded as a stochastic, incoherent and unwanted signal. However, at a closer look, noise also contains coherent signals which can be used to characterize its sources and/ or the subsurface.

Here, we propose the use of array seismological methods for engineering purposes to locate and identify small, local noise sources. A detailed knowledge of noise sources enables appropriate measures to be taken to mitigate unwanted noise effects.

As a case study, we report results from a temporary array of ten seismic broadband stations which were installed at the building site of a high-precision physics laboratory.

Standard analyses of power spectra and amplitude measurements indicate that the highest noise amplitudes are caused by heavy trucks passing by. Burst-like coherent waves, excited by vehicles, appear to have a recurring pattern. Using array techniques, we were able to measure the slowness and backazimuth of the coherent arrivals.

These could be identified as Rayleigh waves generated at small pot-holes and bumps of a near-by road and were found to propagate with a speed of 130–200 m/s.

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