Document Type

Article

Department or Administrative Unit

Geological Sciences

Publication Date

1-9-2017

Abstract

The proximity of Southern Ocean storms coupled with seasonal variation in sea ice make Antarctica ideal for the study of microseism sources. We explore frequency-dependent beamforming results using a short-duration, 60 km aperture, broad-band seismic array located on the Whillans Ice Stream, West Antarctica. Locations of single-frequency microseism (13–16 s period) generation are in regions where the continental shelf is ice-free, consistent with previous studies, and show Rayleigh wave sources remaining at consistent backazimuths throughout the duration of the array. Beamforming analysis of daily noise correlations shows that long-period double-frequency microseisms (9–11 s) consist predominantly of Rayleigh waves excited by storms in the Southern Ocean. Modelling of source locations based on wave–wave interaction provides a good fit to our data at these periods. We show that short-period double-frequency microseisms (5–7 s) in Antarctica consist of crustal phase Lg and body waves. Lg arrivals propagate through regions of continental crust and our data show that the Lg energy is generated when storm systems interact with the sea-ice-free continental shelf during austral summers. Ultra-short-period (0.3–2 s) microseismic body waves back project to regions that correlate with oceanic storm systems in both the Southern and Northern Hemispheres.

Comments

This article has been accepted for publication in Geophysics Journal International ©: 2017 the authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

The full-text article from the publisher can be found here.

Journal

Geophysical Journal International

Rights

© The Authors 2017.

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