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Full-Text Articles in Physical Sciences and Mathematics

Characteristics Of Deep Crustal Seismic Anisotropy From A Compilation Of Rock Elasticity Tensors And Their Expression In Receiver Functions, Sarah J. Brownlee, Vera Schulte-Pelkum, Anissha Raju, Kevin Mahan, Cailey Condit, Omero Felipe Orlandini Sep 2017

Characteristics Of Deep Crustal Seismic Anisotropy From A Compilation Of Rock Elasticity Tensors And Their Expression In Receiver Functions, Sarah J. Brownlee, Vera Schulte-Pelkum, Anissha Raju, Kevin Mahan, Cailey Condit, Omero Felipe Orlandini

Environmental Science and Geology Faculty Research Publications

Rocks in the continental crust are long lived and have the potential to record a wide span of tectonic history in rock fabric. Mapping rock fabric in situ at depth requires the application of seismic methods. Below depths of microcrack closure seismic anisotropy presumably reflects the shape and crystallographic preferred orientations influenced by deformation processes. Interpretation of seismic observables relevant for anisotropy requires assumptions on the symmetry and orientation of the bulk elastic tensor. We compare commonly made assumptions against a compilation of 95 bulk elastic tensors from laboratory measurements, including electron backscatter diffraction and ultrasound, on crustal rocks. The …


Investigations Of The Spatial And Temporal Variations Of Sr And Nd Isotopes In Sediments From Two Indian Rivers: Implications To Source Identification, Sonali Pradhan, Jing Zhang, Mark Baskaran, Prabhaker Vasant Shirodkar, Ying Wu, Umesh Kumar Pradhan Apr 2017

Investigations Of The Spatial And Temporal Variations Of Sr And Nd Isotopes In Sediments From Two Indian Rivers: Implications To Source Identification, Sonali Pradhan, Jing Zhang, Mark Baskaran, Prabhaker Vasant Shirodkar, Ying Wu, Umesh Kumar Pradhan

Environmental Science and Geology Faculty Research Publications

Radiogenic isotopes of Sr and Nd provide crucial information on chemical and physical erosion processes, therefore used as tracers for fingerprinting the sources of fluvial sediments. Moreover, elemental geochemistry, 87Sr/86Sr and 143Nd/144Nd signatures in silicate fractions of sediments primarily reflect intricate controls of characteristics and provenance of sediment. A suite of sediment samples collected from two rivers of India, Narmada (large) and Netravati (small) were analyzed for elemental concentrations, 87Sr/86Sr and 143Nd/144Nd in silicate as well as acid-leachable fractions. 87Sr/86Sr in acid-leachable sediment fractions from both the rivers (0.7094 ± 0.0002 for Narmada and 0.7158 ± 0.003 for Netravati) showed …


Velocity Variations And Uncertainty From Transdimensional P-Wave Tomography Of North America, Scott Burdick, Vedran Lekić Mar 2017

Velocity Variations And Uncertainty From Transdimensional P-Wave Tomography Of North America, Scott Burdick, Vedran Lekić

Environmental Science and Geology Faculty Research Publications

High-resolution models of seismic velocity variations constructed using body-wave tomography inform the study of the origin, fate and thermochemical state of mantle domains. In order to reliably relate these variations to material properties including temperature, composition and volatile content, we must accurately retrieve both the patterns and amplitudes of variations and quantify the uncertainty associated with the estimates of each. For these reasons, we image the mantle beneath North America with P-wave traveltimes from USArray using a novel method for 3-D probabilistic body-wave tomography. The method uses a Transdimensional Hierarchical Bayesian framework with a reversible-jump Markov Chain Monte Carlo algorithm …


Investigation Of Firn Aquifer Structure In Southeastern Greenland Using Active Source Seismology, Lynn N. Montgomery, Nicholas Schmerr, Scott Burdick, Richard R. Forster, Lora Koenig, Anatoly Legchenko, Stefan Ligtenberg, Clément Miège, Olivia L. Miller, D. Kip Solomon Feb 2017

Investigation Of Firn Aquifer Structure In Southeastern Greenland Using Active Source Seismology, Lynn N. Montgomery, Nicholas Schmerr, Scott Burdick, Richard R. Forster, Lora Koenig, Anatoly Legchenko, Stefan Ligtenberg, Clément Miège, Olivia L. Miller, D. Kip Solomon

Environmental Science and Geology Faculty Research Publications

In spring of 2011, a perennial storage of water was observed in the firn of the southeastern Greenland Ice Sheet (GrIS), a region of both high snow accumulation and high melt. This aquifer is created through percolation of surface meltwater downward through the firn, saturating the pore space above the ice-firn transition. The aquifer may play a significant role in sea level rise through storage or draining freshwater into the ocean. We carried out a series of active source seismic experiments using continuously refracted P-waves and inverted the first P-arrivals using a transdimensional Bayesian approach where the depth, velocity, and …


Memorium: Bhamidipati Lakshmidhara Kanakadri Somayajulu (1937-2016), Mark Baskaran, R. Ramesh Jan 2017

Memorium: Bhamidipati Lakshmidhara Kanakadri Somayajulu (1937-2016), Mark Baskaran, R. Ramesh

Environmental Science and Geology Faculty Research Publications

The demise of B. L. K. Somayajulu, an illustrious nuclear geochemist, brings great sadness to the community of geo- logists, geochemists and oceanographers in India and elsewhere.