Infrasound is atmospheric sound and vibration below the threshold of human hearing. These low-frequency sounds are generated by large-scale fluid flow and can propagate for thousands of kilometers to provide early warning of natural or man-made hazards. Active open-vent volcanoes, such as Kīlauea, are exceptionally good sound emitters, and scientists are steadily building a continuous baseline of volcano-acoustic activity, including infrasonic tremor from Halemaʻumaʻu and Pu‘u ‘Ō‘ō. Join Milton Garces, Director of the University of Hawaiʻi Infrasound Laboratory, as he talks about “listening” to Kīlauea, Mauna Loa, and Hualālai volcanoes through one of the most advanced infrasound networks in the world.