Seismic Detection of an Active Subglacial Magmatic Complex in Marie Byrd Land, Antarctica

Numerous volcanoes exist in Marie Byrd Land, a highland region of West Antarctica. High heat flow through the crust in this region may influence the stability of the West Antarctic Ice Sheet. Volcanic activity progressed from north to south in the Executive Committee mountain range between the Mioce...

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Bibliographic Details
Published in:Nature Geoscience
Main Authors: Lough, Amanda C., Wiens, Douglas A., Barcheck, C. Grace, Anandakrishnan, Sridhar, Aster, Richard C., Blankenship, Donald D., Huerta, Audrey D., Nyblade, Andrew, Young, Duncan A., Wilson, Terry J.
Format: Text
Language:unknown
Published: ScholarWorks@CWU 2013
Subjects:
cryospheric science
seismology
volcanology
Geology
Geophysics and Seismology
Antarctic
Byrd
Executive Committee Range
Marie Byrd Land
Mount Waesche
West Antarctic Ice Sheet
West Antarctica
Antarc*
Antarctica
Ice Sheet
Online Access:https://digitalcommons.cwu.edu/geological_sciences/19
https://doi.org/10.1038/ngeo1992
Description
Summary:Numerous volcanoes exist in Marie Byrd Land, a highland region of West Antarctica. High heat flow through the crust in this region may influence the stability of the West Antarctic Ice Sheet. Volcanic activity progressed from north to south in the Executive Committee mountain range between the Miocene and Holocene epochs, but there has been no evidence for recent magmatic activity. Here we use a recently deployed seismic network to show that in 2010 and 2011, two swarms of seismic activity occurred at 25–40 km depth beneath subglacial topographic and magnetic highs, located 55 km south of the youngest subaerial volcano in the Executive Committee Range. We interpret the swarm events as deep long-period earthquakes based on their unusual frequency content. Such earthquakes occur beneath active volcanoes, are caused by deep magmatic activity and, in some cases, precede eruptions. We also use radar profiles to identify a prominent ash layer in the ice overlying the seismic swarm. Located at 1,400 m depth, the ash layer is about 8,000 years old and was probably sourced from the nearby Mount Waesche volcano. Together, these observations provide strong evidence for ongoing magmatic activity and demonstrate that volcanism continues to migrate southwards along the Executive Committee Range. Eruptions at this site are unlikely to penetrate the 1.2 to 2-km-thick overlying ice, but would generate large volumes of melt water that could significantly affect ice stream flow.

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