Description
The detection capability of infrasound stations with four-element arrays is limited by spatial aliasing for higher frequencies, causing erroneous frequency identification and signal distortion when sensor spacing is too large. The Brasília Infrasound Station (IS09) of the International Monitoring System, operated by the University of Brasília's Seismological Observatory, exemplifies this issue with its sensors spaced 1 to 2 km apart in Brasília National Park. The Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization is modernizing these stations to improve performance and data accuracy. The CTBT verification system requires detecting nuclear explosions in the 0.02 to 4 Hz range, but IS09 currently detects frequencies below 1 Hz, missing higher frequencies in case of local and regional events. Therefore, there's a need to modernize IS09 by increasing the number of sensors with shorter inter-distances. In this work, modifications are proposed to the IS09 array, adding five new elements, aiming to improve the station's gain and extend the frequency band to satisfy the requirements for detecting local and regional events and mitigate the spatial aliasing for high frequencies. The new proposed array was tested for 40 days using low-cost equipment, achieving a significantly greater number of detections compared to the IS09 four-element array.
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