2012 IRIS Workshop

Receiver functions on ice: Crust, ice and sediment properties for POLENET

J. Chaput: R. Aster: New Mexico Tech, A. Nyblade: S. Anandrakrishnan: Penn State University, S. Hansen: University of Alabama, D. Wiens: Washington University, A. Huerta: Central Washington University

Example fit for ice thickness and sediment thickness/velocity for BYRD station. Where a priori knowledge of ice thickness is unavailable, we must fit a synthetic receiver function through a 3D grid search of reasonable parameters. We may furthermore fit a crust with a variable VP/VS ratio after having correctly modeled the upper ice/sediment layers.

Full-resolution graphics file in original format: 0129.tiff

Through the application of the method described above, we may indeed still retrieve useful information from P-wave receiver functions (PRFs) computed where multiple shallow layers with particularly low velocities exist. In general, interpretation of PRFs via conventional migration approaches suffer greatly due to the existence of ice sheet reverberations which may mask arrivals as late as expected upper mantle P-S conversions. Crustal information may however still be retrieved where such multiples generally mask any crustal conversions. We further use this method, alongside surface wave constraints and previously published crustal studies, to generate a new crustal thickness map of Antarctica.

Acknoweldgements: This research supported by the National Science Foundation Office of Polar Programs. PASSCAL seismic instruments were provided by the Incorporated Research Institutions for Seismology (IRIS) through the PASSCAL Instrument Center at New Mexico Tech. We would like to thank the POLENET field crews and members for their ongoing efforts, as well as members of UNAVCO and PASSCAL for their patience and support.

Keywords: receiver_function, ice, antarctica

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