Man-made noise from jet engines (jet noise) has
been studied extensively, and there is wide agreement that the dominant
noise source is related to turbulence structures within the jet. Recent
acoustic recordings of Subplinian-Plinian volcanic eruptions have shown
that sustained infrasound from these large eruptions resembles a low frequency
form of jet noise. Turbulence structures within the gas-thrust (jet) region
of the eruption column, as well as possible jet-crater interactions, are
candidate sources for the high-amplitude, long-duration jetting signals.
A proper understanding of jet noise sources may one day allow detailed
characterization of the gas-thrust and buoyant plume region using remote
acoustic surveillance. However, many questions remain on the source mechanisms,
characteristics, and applicability of turbulence related noise to other
volcanoes. This talk will present observations of volcanic jet noise from
multiple volcanoes: Mount St. Helens, USA; Tungurahua, Ecuador; and Okmok
and Kasatochi, Alaska. Further, it will discuss the difficulty of recording
and modeling volcanic jet noise, and possible future research areas.