Capturing the Acoustic Radiation Pattern of Strombolian Eruptions using Infrasound Sensors Aboard a Tethered Aerostat, Yasur Volcano, Vanuatu

• Published in: Geophysical research letters 2017-10, Vol.44 (19), p.9672-9680
• Main Authors: Jolly, Arthur D., Matoza, Robin S., Fee, David, Kennedy, Ben M., Iezzi, Alexandra M., Fitzgerald, Rebecca H., Austin, Allison C., Johnson, Richard
• Format: Article
• Language: English
• Subjects: acoustic; Acoustics; Airships; Azimuth; Deployment; directivity; eruption; Eruptions; Explosions; Infrasound; Radiation; Sensor arrays; Sensors; Sound waves; strombolian; Volcanic activity; Volcanoes; Yasur
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1002/2017GL074971

We obtained an unprecedented view of the acoustic radiation from persistent strombolian volcanic explosions at Yasur volcano, Vanuatu, from the deployment of infrasound sensors attached to a tethered aerostat. While traditional ground‐based infrasound arrays may sample only a small portion of the eruption pressure wavefield, we were able to densely sample angular ranges of ~200° in azimuth and ~50° in takeoff angle by placing the aerostat at 38 tethered loiter positions around the active vent. The airborne data joined contemporaneously collected ground‐based infrasound and video recordings over the period 29 July to 1 August 2016. We observe a persistent variation in the acoustic radiation pattern with average eastward directed root‐mean‐square pressures more than 2 times larger than in other directions. The observed radiation pattern may be related to both path effects from the crater walls, and source directionality. Key Points Acoustic wavefield is sampled with infrasound sensors on a tethered aerostat Acoustic radiation is 2 times stronger eastward of the active crater than in other directions Visual observations of eruptions show southeast to eastward directed ballistics for large eruptions