Acoustic and seismic observations of calving events at Bering Glacier, Alaska

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.