Welcome to the Geophysical Institute Infrasound Group home page. Beginning in 1965 the Geophysical Institute at the University of Alaska Fairbanks has installed and operated seven different infrasonic arrays in Alaska, Canada, Sweden and Antarctica. We have conducted extensive researches on the infrasonic signals observed at these arrays from both natural and man-made sources. Reports and publications on this body of past work are available via the links to the REPORTS section at the left.

What is Infrasound? Infrasonic waves are long wavelength low frequency acoustic waves that are below the frequency range of human hearing. They can be detected on the Earth’s surface by an array of specialized microphones operating in the passband from 0.02 to 10 Hertz. Infrasound propagates with little attenuation over great distances from many different natural and man-made sources.

Our present program spans many activities including the installation and operation of two infrasonic arrays, one in Fairbanks, Alaska and the other in Windless Bight, Antarctica. The infrasonic data from these two arrays is sent in real-time to the Geophysical Institute for research and analysis of many different geophysical sources of infrasound. We are developing extensive software for the analysis and description of infrasound signals contained in the data. A catalogue of typical signals for the two array sites is being prepared. We are developing and testing a field microphone calibration unit designed specifically for Chaparral microphones.

Links to more detailed descriptions of our infrasound sites and research activities are given in the panel at the left.