Characteristics of seismic and acoustic signals produced by calving, Bering Glacier, Alaska

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Abstract

[1] We recorded 126 calving and iceberg breakup events from the terminus of the Bering Glacier during five days in August 2008 using seismometers and three small-aperture arrays of infrasound sensors. The seismic signals were typically emergent, narrow-band, and lower-frequency, similar to records at other glaciers. The acoustic records were characterized by shorter-duration, higher-frequency signals with more impulsive onsets. We demonstrate that triangular infrasound arrays permit improved locations of calving events over seismic arrivals that rely on a relatively complicated, poorly known, velocity model. Twenty-six of 35 well-located events occurred on icebergs in Vitus Lake, rather than the glacier face. While our data do not permit a complete description of the source process, the distinctive frequency contents and durations in the seismic and infrasound data suggest that the two data types record different aspects of the same process.

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