Imaging Observations of Thermal Emissions from Augustine Volcano Using a Small Astronomical Camera

Long-exposure visible-light images of Augustine Volcano were obtained using a charge-coupled device (CCD) camera during several nights of the 2006 eruption. The camera was located 105 km away, at Homer, Alaska, yet showed persistent bright emissions from the north flank of the volcano corresponding to steam releases, pyroclastic flows, and rockfalls originating near the summit. The apparent brightness of the emissions substantially exceeded that of the background nighttime scene. The bright signatures in the images are shown to probably be thermal emissions detected near the long-wavelength limit (~1 (u or mu)) of the CCD. Modeling of the emissions as a black-body brightness yields an apparent temperature of 400 to 450 degrees C that likely reflects an unresolved combination of emissions from hot ejecta and cooler material.