"Constraining volcanic eruptions with infrasound"

Jeffrey B. Johnson, University of New Hampshire

Volcanoes efficiently generate low frequency sounds, which are below the threshold of human hearing (<20 Hz), but which contain very high acoustic energy (e.g., sound pressure levels up to 150 dB have been recorded 1 km from the source!). Such high-energy sound waves can be recorded with specialized microphones and used to constrain volcano source processes including: the location of a vent, the depth of source within a conduit, the time history of gas flux, and the changing atmospheric structure. This talk will provide an overview emphasizing the value of eruption infrasound using case studies from volcanoes in the Americas, Russia, and Antarctica.