Wind-induced seismic noise at the Princess Elisabeth Antarctica Station

• Main Authors: Frankinet, Baptiste, Lecocq, Thomas, Camelbeeck, Thierry
• Format: Text
• Language: English
• Published: 2020
• Subjects: Antarc*; Antarctica
• Online Access: https://doi.org/10.5194/tc-2020-267; https://tc.copernicus.org/preprints/tc-2020-267/

Icequakes are the result of processes occurring within the ice mass, or between the ice and its environment. Studying icequakes provide a unique view on the ice dynamics, specifically on the basal conditions. Changes in conditions due to environmental, or climate, changes, are reflected in icequakes. Counting and characterizing icequakes is thus essential to monitor them. Most of the icequakes recorded by the seismic station at the Belgian Princess Elisabeth Antarctica Station (PE) have small amplitudes corresponding to maximal displacements of a few nanometres. Their detection threshold is highly variable because of the rapid and strong changes in the local seismic noise level. In this study, we evaluated the influence of katabatic winds on the noise measured by the well-protected PE surface seismometer. Our purpose is to identify whether the lack of icequakes detection during some periods could be associated with variations in the processes generating them or simply to a stronger seismic noise linked to stronger wind conditions. We observed that the wind mainly influences seismic noise at frequencies greater than 1 Hz. The seismic noise level well correlates linearly with the wind velocity, but this correlation follows different linear laws at wind velocity lower and greater than 6 m/s, with a respective variation of 0.4 dB/(m/s) and 1.4 dB/(m/s). These results allowed presenting a model and synthetic spectrogram that explain the behaviour of the wind-induced seismic noise at PE. This model enables us partially removing the influence of wind impact from the original seismic dataset, which improves the observation of cryoseismic activity near the PE station.