LETTERS A recent volcanic eruption beneath the West Antarctic ice sheet

• Main Authors: Hugh F. J. Corr, David, G. Vaughan
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2008
• Subjects: Antarctic; Hudson; Hudson Mountains; West Antarctic Ice Sheet; Antarc*; Ice Sheet
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.306.4886; http://ruby.fgcu.edu/courses/twimberley/EnviroPhilo/Corr.pdf

Indirect evidence suggests that volcanic activity occurring beneath the West Antarctic ice sheet influences ice flow and sheet stability1–3. However, only volcanoes that protrude through the ice sheet4 and those inferred from geophysical techniques1,2 have been mapped so far. Here we analyse radar data from the Hudson Mountains, West Antarctica5, that contain reflections from within the ice that had previously been interpreted erroneously as the ice-sheet bed. We show that the reflections are present within an elliptical area of about 23,000 km2 that contains tephra from an explosive volcanic eruption. The tephra layer is thickest at a subglacial topographic high, which we term the Hudson Mountains Subglacial Volcano. The layer depth dates the eruption at 207 BC ± 240 years, which matches exceptionally strong but previously unattributed conductivity signals in nearby ice cores. The layer contains 0.019–0.31 km3 of tephra, which implies a volcanic explosive index of 3–4. Production