Contributions to sea level rise from rapidly retreating marine-terminating glaciers are large and increasing. Strong increases in iceberg calving occur during retreat, which allows mass transfer to the ocean at a much higher rate than possible through surface melt alone. To study this process, we deployed an 11-sensor passive seismic network at Columbia Glacier, Alaska, during 2004–2005. We show that calving events generate narrow-band seismic signals, allowing frequency domain detections. Detection parameters were determined using direct observations of calving and validated using three statistical methods and hypocenter locations. The 1–3 Hz detections provide a good measure of the temporal distribution and size of calving events. Possible source mechanisms for the unique waveforms are discussed, and we analyze potential forcings for the observed seismicity.
|Title||Seismic detection and analysis of icequakes at Columbia Glacier, Alaska|
|Authors||Shad O'Neel, Hans P. Marshall, Daniel E. McNamara, William Tad Pfeffer|
|Publication Subtype||Journal Article|
|Series Title||Journal of Geophysical Research|
|Record Source||USGS Publications Warehouse|
|USGS Organization||Alaska Science Center|