Glacial rumblings from Jakobshavn ice stream, Greenland ...

• Main Authors: Steffen, K., Tang, C., Rial, J. A.
• Format: Text
• Language: English
• Published: The University of North Carolina at Chapel Hill University Libraries 2009
• Subjects: Greenland; Jakobshavn Isbræ; glacier; Jakobshavn; Jakobshavn isbræ
• Online Access: https://dx.doi.org/10.17615/rjeq-6446; https://cdr.lib.unc.edu/concern/articles/d504rv49q

Abstract The steep increase in Greenland’s glacial earthquake activity detected by the Global Seismographic Network since the late 1990s suggests that a close inspection of these events might provide clues to the nature and origin of such seismic activity. Here we discuss the detection of large, unexpected seismic events of extraordinarily long duration (10–40 min) occurring about once every 2 days, and localized in the ice stream that feeds the Earth’s fastest-moving glacier (Jakobshavn Isbræ) from the east. These ‘glacial rumblings’ represent an ice-mass wasting process that is greater and more frequent than glacial earthquakes have suggested. Probably triggered by calving, the rumblings are all very similar regardless of duration, and all end with a sharp, earthquake-like event in which the largest seismic amplitude is in the rumbling and that might signal the collapse of large ice masses upstream. By calculating the total amount of seismic energy released as rumblings, we estimate that the maximum ...