Physics Department Seminar University of Alaska Fairbanks

J O U R N A L    C L U B

Volcanic Jet Noise
David Fee
GI, Univ of Alaska Fairbanks

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.

Friday, 1 Oct 2010
Globe Room, Elvey Building
3:45 PM