English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Abstract. We present velocity observations of a glacier outlet in Vatnajokull, Iceland, deduced from interferometric SAR (InSAR) data obtained during the ERS1/2 tandem mission in 1995–2000. More than a 50% decrease in glacier velocity was observed subsequent to a large jokulhlaup from the subglacial lake Grimsvotn in 1996. The glacier had not reached its former flow rate in 2000. The jokulhlaup damaged the lake's ice-dam causing persistent drainage from the lake. InSAR based studies of water accumulation within Grimsvotn suggest that a leakage of >3 m3 s−1 prevailed throughout our study period. We suggest that the lake leakage kept open a tunnel at low water pressure underneath the whole length of the glacier. The tunnel flow drained water from its surroundings, hence lowering the water pressure of a distributed drainage system, underneath the upper and centre parts of the glacier, which prior to the jokulhlaup sustained significant basal sliding. This is in accordance with theoretical prediction that tunnel flow in a steady state may cause slow-down in glacier velocity by reducing the subglacial water pressure. The width of the affected areas was ~5 km on the upper part of the glacier and ~8 km on the centre part of the glacier. This indicates that the water pressure reduction propagates laterally from the tunnel over a distance of a few km.

Reduced glacier sliding caused by persistent drainage from a subglacial lake