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Tidal influence on Rutford Ice Stream, West Antarctica: Observations of surface flow and basal processes from closely spaced GPS and passive seismic stations

journal contribution
posted on 2023-05-17, 15:20 authored by Adalgeirsdottir, G, Smith, AM, Murray, T, Matt KingMatt King, Makinson, K, Nicholls, KW, Behar, AE
High-resolution surface velocity measurements and passive seismic observations from Rutford Ice Stream, West Antarctica, 40km upstream from the grounding line are presented. These measurements indicate a complex relationship between the ocean tides and currents, basal conditions and ice-stream flow. Both the mean basal seismicity and the velocity of the ice stream are modulated by the tides. Seismic activity increases twice during each semi-diurnal tidal cycle. The tidal analysis shows the largest velocity variation is at the fortnightly period, with smaller variations superimposed at diurnal and semi-diurnal frequencies. The general pattern of the observed velocity is two velocity peaks during each semi-diurnal tidal cycle, but sometimes three peaks are observed. This pattern of two or three peaks is more regular during spring tides, when the largest-amplitude velocity variations are observed, than during neap tides. This is the first time that velocity and level of seismicity are shown to correlate and respond to tidal forcing as far as 40km upstream from the grounding line of a large ice stream.

History

Publication title

Journal of Glaciology

Volume

54

Issue

187

Pagination

715-724

ISSN

0022-1430

Department/School

School of Geography, Planning and Spatial Sciences

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the earth sciences