Title: Avalanches, Artillery, and Acoustics: Explosion Infrasound in a Dynamic Snowpack

Abstract: Avalanches, hazardous accumulations of snow moving downhill, commonly threaten populated areas and critical infrastructure. Current avalanche monitoring techniques include seismic, radar, and infrasound technologies. Infrasound monitoring is cost-effective and enables real-time location and timing of snow avalanches using sound below the threshold of human hearing that is produced by an avalanche as it moves. It is well known in avalanche monitoring that infrasound-based avalanche detection systems become less sensitive as the winter season progresses. This is attributed to snow burying the sensors, related source characteristics, or other influences that are poorly understood at scale. I seek to: 1) characterize environmental influences on recorded infrasound (site response); and 2) identify non-linear source characteristics unrelated to site response. In Little Cottonwood Canyon, Utah, from March 15 to April 2023, I identify and analyze differences in acoustic signal recorded by a total of six infrasound sensors. Through this research, I aim to improve understanding of the factors that reduce the effectiveness of infrasound-monitoring, and improve location-accuracy of infrasound-based avalanche detection systems. This research will benefit avalanche forecasters, departments of transportation, and utility companies who utilize infrasound monitoring technology, with the hope of reducing the likelihood of loss of life due to avalanches.

Advisor: Jeffrey Johnson

Committee: Jacob Anderson and Scott Havens