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Articles 1 - 5 of 5
Full-Text Articles in Physical Sciences and Mathematics
Refractory Black Carbon (Rbc) Variability In A 47-Year West Antarctic Snow And Firn Core, Marquetto Luciano, Susan Kaspari, Jefferson Cardia Simões
Refractory Black Carbon (Rbc) Variability In A 47-Year West Antarctic Snow And Firn Core, Marquetto Luciano, Susan Kaspari, Jefferson Cardia Simões
All Faculty Scholarship for the College of the Sciences
Black carbon (BC) is an important climate-forcing agent that affects snow albedo. In this work, we present a record of refractory black carbon (rBC) variability, measured from a 20m deep snow and firn core drilled in West Antarctica (79°55’34.600” S, 94°21’13.3”W, 2122m above sea level) during the 2014–2015 austral summer. This is the highest elevation rBC record from West Antarctica. The core was analyzed using the Single Particle Soot Photometer (SP2) coupled to a CETAC Marin-5 nebulizer. Results show a well-defined seasonality with geometric mean concentrations of 0.015 μg L-1 for the wet season (austral summer–fall) and 0.057 μg …
The Crust And Upper Mantle Structure Of Central And West Antarctica From Bayesian Inversion Of Rayleigh Wave And Receiver Functions, Weisen Shen, Audrey D. Huerta, J. Paul Winberry
The Crust And Upper Mantle Structure Of Central And West Antarctica From Bayesian Inversion Of Rayleigh Wave And Receiver Functions, Weisen Shen, Audrey D. Huerta, J. Paul Winberry
All Faculty Scholarship for the College of the Sciences
We construct a new seismic model for central and West Antarctica by jointly inverting Rayleigh wave phase and group velocities along with P wave receiver functions. Ambient noise tomography exploiting data from more than 200 seismic stations deployed over the past 18 years is used to construct Rayleigh wave phase and group velocity dispersion maps. Comparison between the ambient noise phase velocity maps with those constructed using teleseismic earthquakes confirms the accuracy of both results. These maps, together with P receiver function waveforms, are used to construct a new 3-D shear velocity (Vs) model for the crust and uppermost mantle …
The Mantle Transition Zone Beneath West Antarctica: Seismic Evidence For Hydration And Thermal Upwellings, E. L. Emry, A. A. Nyblade, J. Juliá, S. Anandakrishnan, R. C. Aster, D. A. Wiens, Audrey D. Huerta, T. J. Wilson
The Mantle Transition Zone Beneath West Antarctica: Seismic Evidence For Hydration And Thermal Upwellings, E. L. Emry, A. A. Nyblade, J. Juliá, S. Anandakrishnan, R. C. Aster, D. A. Wiens, Audrey D. Huerta, T. J. Wilson
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Although prior work suggests that a mantle plume is associated with Cenozoic rifting and volcanism in West Antarctica, the existence of a plume remains conjectural. Here we use P wave receiver functions (PRFs) from the Antarctic POLENET array to estimate mantle transition zone thickness, which is sensitive to temperature perturbations, throughout previously unstudied parts of West Antarctica. We obtain over 8000 high‐quality PRFs using an iterative, time domain deconvolution method filtered with a Gaussian width of 0.5 and 1.0, corresponding to frequencies less than ∼0.24 and ∼0.48 Hz, respectively. Single‐station and common conversion point stacks, migrated to depth using the …
Seismic Observations Of Transient Subglacial Water-Flow Beneath Macayeal Ice Stream, West Antarctica, J. Paul Winberry, Sridhar Anandakrishnan, Richard B. Alley
Seismic Observations Of Transient Subglacial Water-Flow Beneath Macayeal Ice Stream, West Antarctica, J. Paul Winberry, Sridhar Anandakrishnan, Richard B. Alley
All Faculty Scholarship for the College of the Sciences
New seismic observations of harmonic tremors beneath MacAyeal Ice Stream, West Antarctica are reported. Each of the two tremor events that we recorded during a six week period had sustained arrival of 3 Hz energy for approximately 10 minutes. During that time the source location migrated a few kilometers. The harmonic nature of the tremors is interpreted as the result of resonance in subglacial water-filled cracks and conduits. The duration, monochromatic nature, and movement of the tremor indicate that the source mechanism is likely flow in the subglacial water system resulting from the discharge from a small subglacial lake. Our …
Basal Mechanics Of Ice Streams: Insights From The Stick-Slip Motion Of Whillans Ice Stream, West Antarctica, J. Paul Winberry, Sridhar Anandakrishnan, Richard B. Alley, Robert A. Bindschadler, Matt A. King
Basal Mechanics Of Ice Streams: Insights From The Stick-Slip Motion Of Whillans Ice Stream, West Antarctica, J. Paul Winberry, Sridhar Anandakrishnan, Richard B. Alley, Robert A. Bindschadler, Matt A. King
All Faculty Scholarship for the College of the Sciences
The downstream portion of Whillans Ice Stream, West Antarctica, moves primarily by stick-slip motion. The observation of stick-slip motion suggests that the bed is governed by velocity-weakening physics and that the basal physics is more unstable than suggested by laboratory studies. The stick-slip cycle of Whillans Ice Plain exhibits substantial variability in both the duration of sticky periods and in slip magnitude. To understand this variability, we modeled the forces acting on the ice stream during the stick phase of the stick-slip cycle. The ocean tides introduce changes in the rate at which stress is applied to the ice plain. …