Full Waveform Ambient Noise Tomography
While densification of seismic networks throughout Antarctica (Fig. 1) has revealed much about the geologic features and the tectonic history of the continent, outside the boundaries of the existing network coverage, particularly in sparsely-instrumented parts of East Antarctica as well as in the Weddell Sea and Thurston Island regions of West Antarctica, current tomographic models have poor resolution or show conflicting upper mantle structures (Fig. 2). Further analysis is needed to fully exploit existing Antarctic seismic datasets and to more thoroughly investigate the tectonic structures in these regions.
Figure 1. Map of Antarctic bedrock topography (Fretwell et al., 2013) with seismic stations denoted by black and white squares. Hatched line marks the southern boundary of the West Antarctic Rift System (WARS) and dotted lines denote possible rift arms within the WARS, east and north of the Bentley Subglacial Trench (BST). The colored boxes mark targeted locations of focus for this study. Blue: Eastern extent of the West Antarctic Rift (EWAR); Red: Weddell Sea (WS) and Ronne-Filchner Ice Shelf (RFIS); Yellow: Dronning Maud Land (DML): and Green: Wilkes and Aurora Subglacial Basins (WSB and ASB). AP: Antarctic Peninsula, EWM: Ellsworth-Whitmore Mountains, GSM: Gamburtsev Subglacial Mountains, LR: Lambert Rift, MBL: Marie Byrd Land, NTAM: Northern Transantarctic Mountains, RIS: Ross Ice Shelf, TAM: Transantarctic Mountains, VH: Vostok Highlands.
We will further examine geographic target areas (Fig. 1) within Antarctica using a new tomographic model generated with an advanced full-waveform tomography method and a unique dataset of empirical Green's functions extracted from ambient seismic noise. This approach will improve resolution in sparsely-instrumented regions and has been shown to more accurately resolve structure than traditional tomographic approaches (Chen et al., 2007; Fichtner et al., 2010).
This work is in progress, funded by National Science Foundation grant OPP-1643873.