Background Noise Characterization and Event Detection at an Infrasound Array in Oklahoma

It has been shown that there are many natural and manmade sources of infrasound, or sound below the threshold of human hearing (20 Hz). Some of these sources include severe storms, oceans, volcanos, earthquakes, and explosions. These infrasound signals can propagate hundreds to thousands of kilometers depending on the frequency and atmospheric conditions. However, detecting these signals can be difficult depending on the local wind conditions, background noise, and frequency band of interest. The current work investigates these background conditions and the detection of known events at a 3 microphone infrasound array located in Stillwater, OK between 2016 and 2021. The background noise was investigated by attempting to identify local or consistent infrasound sources as well as quantify the array's sensitivity to wind. Characterizing the background noise allows for better detection of other infrasound sources of interest. Therefore, this work will report the findings on the local "noise floor" as well as possible sources for infrasound contamination. Additionally, several events that were detected utilizing f/k analysis and an adaptive f detector will be shown.