Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Physical Sciences and Mathematics
Evaluating Hydration And Artificial Aging Effects On The Paleointensity In Natural Glass, Sebastian Fearn
Evaluating Hydration And Artificial Aging Effects On The Paleointensity In Natural Glass, Sebastian Fearn
Theses and Dissertations
Young natural volcanic glasses have been successfully used to recover Earth’s geomagnetic field intensity (paleointensity). However, the magnetic stability and reliability of volcanic glass as a paleomagnetic recorder over geologic time is unclear. Paleointensity estimates may be influenced by natural processes that alter magnetic mineralogy. Previous results from paleointensity and rock magnetic experiments suggest that post-emplacement hydrothermal alteration can alter the magnetic remanence and can possibly cause paleointensity experiments to fail. Low-temperature hydration and natural relaxation of the glass structure over time may also adversely impact paleointensity results. In this study, rhyolitic and basaltic glass specimens underwent artificial aging and …
Neural Network Models For Nuclear Treaty Monitoring: Enhancing The Seismic Signal Pipeline With Deep Temporal Convolution, Joshua T. Dickey
Neural Network Models For Nuclear Treaty Monitoring: Enhancing The Seismic Signal Pipeline With Deep Temporal Convolution, Joshua T. Dickey
Theses and Dissertations
Seismic signal processing at the IDC is critical to global security, facilitating the detection and identification of covert nuclear tests in near-real time. This dissertation details three research studies providing substantial enhancements to this pipeline. Study 1 focuses on signal detection, employing a TCN architecture directly against raw real-time data streams and effecting a 4 dB increase in detector sensitivity over the latest operational methods. Study 2 focuses on both event association and source discrimination, utilizing a TCN-based triplet network to extract source-specific features from three-component seismograms, and providing both a complimentary validation measure for event association and a one-shot …
A Feasibility Study Of Microbialites As Paleomagnetic Recorders, Ji-In Jung
A Feasibility Study Of Microbialites As Paleomagnetic Recorders, Ji-In Jung
Theses and Dissertations
Microbialites are carbonate organosedimentary deposits formed by benthic microbial communities that trap and bind detrital sediments, and/or inorganic and biologically influenced calcification. Any ferromagnetic particles incorporated into the microbialite structure have the potential to preserve variations in Earth’s magnetic field. A paleomagnetic record in microbialites would be useful for reconstructing the geomagnetic field because it may record at a high temporal resolution based on estimated growth rates, thus preserving relatively short-period variations of the Earth’s magnetic field. In addition, microbialites can be found in the geologic record going back ~3.5 Ga, hence potentially providing information on very ancient variations in …