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Full-Text Articles in Geophysics and Seismology
Glacial Earthquakes And Precursory Seismicity Associated With Thwaites Glacier Calving, J. Paul Winberry, Audrey D. Huerta, Sridhar Anandakrishnan, Richhard C. Aster, Andrew A. Nyblade, Douglas A. Wiens
Glacial Earthquakes And Precursory Seismicity Associated With Thwaites Glacier Calving, J. Paul Winberry, Audrey D. Huerta, Sridhar Anandakrishnan, Richhard C. Aster, Andrew A. Nyblade, Douglas A. Wiens
All Faculty Scholarship for the College of the Sciences
We observe two (~MS 3) long‐period (10–30 s) seismic events that originate from the terminus of Thwaites Glacier, Antarctica. Serendipitous acquisition of satellite images confirm that the seismic events were glacial earthquakes generated during the capsizing of icebergs. The glacial earthquakes were preceded by 6 days of discrete high‐frequency seismic events that can be observed at distances exceeding 250 km. The high‐frequency seismicity displays an increasing rate of occurrence, culminating in several hours of sustained tremor coeval with the long‐period events. A series of satellite images collected during this precursory time period show that the high‐frequency events and …
Seismic Observations Of Transient Subglacial Water-Flow Beneath Macayeal Ice Stream, West Antarctica, J. Paul Winberry, Sridhar Anandakrishnan, Richard B. Alley
Seismic Observations Of Transient Subglacial Water-Flow Beneath Macayeal Ice Stream, West Antarctica, J. Paul Winberry, Sridhar Anandakrishnan, Richard B. Alley
All Faculty Scholarship for the College of the Sciences
New seismic observations of harmonic tremors beneath MacAyeal Ice Stream, West Antarctica are reported. Each of the two tremor events that we recorded during a six week period had sustained arrival of 3 Hz energy for approximately 10 minutes. During that time the source location migrated a few kilometers. The harmonic nature of the tremors is interpreted as the result of resonance in subglacial water-filled cracks and conduits. The duration, monochromatic nature, and movement of the tremor indicate that the source mechanism is likely flow in the subglacial water system resulting from the discharge from a small subglacial lake. Our …