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Samantha E. Hansen

Assistant Professor

shansen@ua.edu
(205) 348-7089
2031 Bevill Bldg.

Education

BS, Geological Engineering, University of Wisconsin, 2000

MS, Geology and Geophysics, University of Wisconsin, 2002

PhD, Geology and Geophysics, University of California, Santa Cruz, 2007

Post-Doctoral, Pennsylvania State University

Courses Taught

GEO 101: The Dynamic Earth
GEO 407/507: Seismology
GEO 435/535/635: Honors and Graduate Seminar in Geology
GEO 542: Geodynamics

Research Interests

My research is driven by the underlying goal to advance our understanding of fundamental geodynamic processes, such as volcanism, mountain building, continental rifting, and craton formation. To this end, I employ a wide range of geological and geophysical tools emphasizing earthquake seismology, active tectonics, and the analysis of seismic data to investigate structure and infer associated earth processes. Past and current research projects have focused on a variety of different geographic locations including Hawaii, Costa Rica, Saudi Arabia, Africa, and Antarctica.

Current Research Projects

Evaluating Tectonic Models for Antarctica

Numerous candidate models for the geologic processes shaping the Antarctic continent have been proposed. In order to discriminate between them, detailed images of the upper mantle structure are required.  Using newly available data from various Antarctic seismic networks, I am constructing the first continental-scale P-wave tomography model for Antarctica using an adaptively parameterized tomography method.  This method combines regional seismic travel-time datasets in the context of a global model to create a composite continental-scale model of upper mantle structure.  Improved characterization of the seismic structure beneath Antarctica not only provides new information about the nature of Antarctic tectonics but also helps to advance understanding of important global processes.

AntTomo
Map view image at 150 km depth of the adaptively parameterized P-wave tomography model beneath Antarctica.


Transantarctic Mountains Northern Network (TAMNNET)

Current constraints on the crustal thickness and seismic velocity structure beneath the Transantarctic Mountains (TAMs) and the Wilkes Subglacial Basin (WSB) are limited, leading to uncertainties over competing geologic models that have been suggested to explain their formation. To broaden the investigation of this region, I am operating a 15-station array across the northern TAMs and the WSB, which fills a major gap in seismic coverage. Data from TAMNNET is being combined with that from other previous and ongoing seismic initiatives and is being analyzed to generate an unprecedented image of the seismic structure beneath the TAMs and the WSB.  Results from this work will be used to differentiate between competing tectonic models, thereby resolving how the TAMs and WSB originated and how their formation relates to Antarctica’s geologic history.

TAMs SeismicInstall

(left) Transantarctic Mountains.  (right) Installing a TAMNNET seismic station.

Research Group Members

Jordan Graw, PhD student

Lindsey Kenyon, MS student

Greg Brenn, MS student

Representative Publications

Hansen, S.E., J.H. Graw, L.M. Kenyon, A.A. Nyblade, D.A. Wiens, R.C. Aster, A.D. Huerta, S. Anandakrishnan, and T. Wilson, Imaging the Antarctic Mantle using Adaptively Parameterized P-wave Tomography: Evidence for Heterogeneous Structure beneath West Antarctica, Earth Planet. Sci. Lett., 2014.  Hansen_EPSL_2014.pdf (11 downloads)

Hansen, S.E., H.R. DeShon, M.M. Driskell, and A.M.S. Al-Amri, Investigating the P-wave Velocity Structure beneath Harrat Lunayyir, northwestern Saudi Arabia, using Double-Difference Tomography and Earthquakes from the 2009 Seismic Swarm, J. Geophys. Res., 118, 1-13, 2013.  Hansen_JGR_2013.pdf (7 downloads)

Hansen, S.E. and A.A. Nyblade, The Deep Seismic Structure of the Ethiopia/Afar Hotspot and the African Superplume, Geol. J. Int., 194, 118-124, 2013.  HansenNyblade_GJI_2013.pdf (9 downloads)

Heeszel, D.S., D.A. Wiens, A.A. Nyblade, S.E. Hansen, M. Kanao, M. An, and Y. Zhao, Rayleigh wave constraints on the structure and tectonic history of the Gamburtsev Subglacial Mountains, East Antarctica, J. Geophys. Res., 118, 2138-2153, 2013.  Heeszel_JGR_20131.pdf (7 downloads)

Lloyd, A.J., A.A. Nyblade, D.A. Wiens, P.J. Shore, S.E. Hansen, M. Kanao, and D. Zhao, Upper mantle seismic structure beneath central East Antarctica from body wave tomography: Implications for the origin of the Gamburtsev Subglacial Mountains, Geochem. Geophys. Geosys., 14, doi: 10.1002/ggge.20098, 2013.  Lloyd_G-cubed_2013.pdf (7 downloads)

Kanao, M., S.E. Hansen, K. Kamiyama, D. Wiens, T. Higashi, A.A. Nyblade, A. Watanabe, Crustal structure from the Lützow-Holm Bay to the inland plateau of East Antarctica, based on gravity surveys and broadband seismic deployments, Tectonphys., 572-573, 100-110, 2012.  Kanao_Tectonophysics_2012.pdf (6 downloads)

Hansen, S.E., A.A. Nyblade, and M.H. Benoit, Mantle structure beneath Africa and Arabia from adaptively parameterized P-wave tomography: Implications for the origin of Cenozoic Afro-Arabian tectonism, Earth Planet. Sci. Lett., 319-320, 23-34, 2012.  Hansen_EPSL_20121.pdf (8 downloads)

Hansen, S.E., A.A. Nyblade, D. Heeszel, D.A. Wiens, P. Shore, and M. Kanao, Crustal Structure of the Gamburtsev Mountains, East Antarctica, from S-wave Receiver Functions and Rayleigh Wave Phase Velocities, Earth Planet. Sci. Lett., 300, 395-401, 2010.  Hansen_EPSL_2010.pdf (8 downloads)

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