Tidal forcing of basal seismicity of ice stream C, West Antarctica, observed far inland

Research output: Contribution to journalArticle

97 Citations (Scopus)

Abstract

The seismicity rate beneath the downglacier 85 km of ice stream C, West Antarctica, is modulated by the tide. The tide beneath the Ross Ice Shelf modifies the force balance of the ice stream basal environment enough to change the rate of basal microearthquake generation by an order of magnitude. This tidal forcing travels up the ice stream as an attenuating wave at approximately 1.6m s-1 and is detectable 85km from the grounding line. We successfully model this behavior as an elastic ice stream underlain by a viscous substrate of viscosity η and thickness hb and calculate that the substrate has an apparent stiffness η/hb of O(108)Pa s m-1. This finding suggests that the conditions of the till layer at the bed of ice stream C are similar to those of ice stream B and that the reason for the recent stagnation of ice stream C is other than loss of till. We further find that the ice stream at the grounding line is more strongly affected by ice shelf processes than by the basal shear stress.

Original languageEnglish (US)
Article number97JB01073
Pages (from-to)15183-15196
Number of pages14
JournalJournal of Geophysical Research B: Solid Earth
Volume102
Issue numberB7
StatePublished - Jan 1 1997

Fingerprint

ice stream
Ice
Antarctic regions
Antarctica
seismicity
ice
grounding line
ice shelf
tides
Tides
Electric grounding
Ross ice shelf
tide
land ice
substrate
microearthquake
travel
shear stress
stiffness
beds

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Oceanography
  • Forestry
  • Aquatic Science
  • Ecology
  • Condensed Matter Physics
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Physical and Theoretical Chemistry
  • Polymers and Plastics
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Materials Chemistry
  • Palaeontology

Cite this

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title = "Tidal forcing of basal seismicity of ice stream C, West Antarctica, observed far inland",
abstract = "The seismicity rate beneath the downglacier 85 km of ice stream C, West Antarctica, is modulated by the tide. The tide beneath the Ross Ice Shelf modifies the force balance of the ice stream basal environment enough to change the rate of basal microearthquake generation by an order of magnitude. This tidal forcing travels up the ice stream as an attenuating wave at approximately 1.6m s-1 and is detectable 85km from the grounding line. We successfully model this behavior as an elastic ice stream underlain by a viscous substrate of viscosity η and thickness hb and calculate that the substrate has an apparent stiffness η/hb of O(108)Pa s m-1. This finding suggests that the conditions of the till layer at the bed of ice stream C are similar to those of ice stream B and that the reason for the recent stagnation of ice stream C is other than loss of till. We further find that the ice stream at the grounding line is more strongly affected by ice shelf processes than by the basal shear stress.",
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Tidal forcing of basal seismicity of ice stream C, West Antarctica, observed far inland. / Anandakrishnan, Sridhar; Alley, Richard B.

In: Journal of Geophysical Research B: Solid Earth, Vol. 102, No. B7, 97JB01073, 01.01.1997, p. 15183-15196.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Tidal forcing of basal seismicity of ice stream C, West Antarctica, observed far inland

AU - Anandakrishnan, Sridhar

AU - Alley, Richard B.

PY - 1997/1/1

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N2 - The seismicity rate beneath the downglacier 85 km of ice stream C, West Antarctica, is modulated by the tide. The tide beneath the Ross Ice Shelf modifies the force balance of the ice stream basal environment enough to change the rate of basal microearthquake generation by an order of magnitude. This tidal forcing travels up the ice stream as an attenuating wave at approximately 1.6m s-1 and is detectable 85km from the grounding line. We successfully model this behavior as an elastic ice stream underlain by a viscous substrate of viscosity η and thickness hb and calculate that the substrate has an apparent stiffness η/hb of O(108)Pa s m-1. This finding suggests that the conditions of the till layer at the bed of ice stream C are similar to those of ice stream B and that the reason for the recent stagnation of ice stream C is other than loss of till. We further find that the ice stream at the grounding line is more strongly affected by ice shelf processes than by the basal shear stress.

AB - The seismicity rate beneath the downglacier 85 km of ice stream C, West Antarctica, is modulated by the tide. The tide beneath the Ross Ice Shelf modifies the force balance of the ice stream basal environment enough to change the rate of basal microearthquake generation by an order of magnitude. This tidal forcing travels up the ice stream as an attenuating wave at approximately 1.6m s-1 and is detectable 85km from the grounding line. We successfully model this behavior as an elastic ice stream underlain by a viscous substrate of viscosity η and thickness hb and calculate that the substrate has an apparent stiffness η/hb of O(108)Pa s m-1. This finding suggests that the conditions of the till layer at the bed of ice stream C are similar to those of ice stream B and that the reason for the recent stagnation of ice stream C is other than loss of till. We further find that the ice stream at the grounding line is more strongly affected by ice shelf processes than by the basal shear stress.

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