Fuego Volcano (14°29′N, 90°53′W, 3800 m) is the southernmost vent of the north-south–trending Fuego-Acatenango volcanic complex. A basaltic-andesite stratovolcano, Fuego has had more than 60 subplinian eruptions since A.D. 1524, making it one of the most active volcanoes in the world. Since 1999, Fuego has exhibited continuous low-level activity, which alternates between periods of lava effusion with Strombolian explosions and periods of discrete explosions with no lava effusion. We analyzed explosions recorded on a broadband seismometer and infrasonic microphones in June and July 2008. The explosions were identified through a combination of visual field observations and the examination of infrasound records. Acoustic waveform cross-correlation indicated a highly repetitive source appropriate for investigating temporal variations in the wave field. The primary focus of this study is a time period from 8 to 27 June 2008, which included the emergence of a new lava flow. Using seismic coda wave interferometry analysis of 159 well-recorded explosions, we detected short-term relative changes in the velocity structure ranging from −0.23% to 0.61%. This rapid variation may indicate minor fluctuations in volatile content. Variations in seismic and acoustic wave arrival time differences, which might result from changes in source depth, are attributed to wind speed variations.

The Bering Glacier, located in Southeastern Alaska, extends from the Bagley Ice Field to Vitus Lake, a tidally influenced fresh-water lake draining into the Gulf of Alaska. Calving events from the grounded and floating portions of the terminus are shown to produce both acoustic and seismic signals measurable with infrasound detectors and geophones, respectively. Based on the complex, emergent seismic signals recorded from calving events during a short-term experiment conducted at the Bering Glacier in the summer of 2007, we sought another technique for accurately locating these events. In August 2008 we deployed three small-aperture arrays of infrasound detectors to test their utility at determining the locations of subaerial calving events. Despite the complex nature of both the seismic and acoustic signals generated by calving, through the determination of azimuth from three small arrays of infrasound detectors, we were able to accurately locate both terminus calving and iceberg breakup events without relying on first motion picks for hypocenter locations.