Publication Date:
2017-04-04
Description:
The inner regions of the Antarctic continent are generally regarded as nearly aseismic, although microseismicity is known to
occur beneath some outlet ice streams, related to the interaction between the fast flowing ice and the bedrock. Here we show the
occurrence of unusual earthquakes beneath an Antarctic outlet glacier that share almost the same magnitude, pointing to the
repeated rupture of a single asperity. These seismic events produce waveforms with very high similarity and uncommon spectrum
and are tightly clustered in space but, unlike other reported instances of repeating earthquakes on a patch of the San Andreas Fault,
they occur in frequent irregular swarms. Evidence locates these events at the rock–ice interface under the glacier, and shows the
existence of stick–slip motion on a smaller scale than the large slow slip events detected by global seismographs. Seismic
behaviour of large glaciers can presumably be connected to surges in ice motion. This study determines a little known environment
for fracture dynamics studies, while also contributing to the understanding of the coupling processes between fast flowing glaciers
and bedrock that influence ice stream evolution and stability.
Description:
Progetto Nazionale di Ricerca in Antartide (PNRA)
Antarctica New Zealand (ANZ)
Description:
Published
Description:
151–158
Description:
3.3. Geodinamica e struttura dell'interno della Terra
Description:
JCR Journal
Description:
reserved
Keywords:
Glacial earthquakes
;
Glacial dynamics
;
Gutenberg-Richter relationship
;
Double-difference hypocentre location
;
Repeating earthquake
;
04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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